Catalogue of ambulatory care sensitive conditions (ACSC) for Germany 2025: protocol of a group consensus study

Catalogue of ambulatory care sensitive conditions (ACSC) for Germany 2025: protocol of a group consensus study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Study protocol Catalogue of ambulatory care sensitive conditions (ACSC) for Germany 2025: protocol of a group consensus study Gina Wittlinger, Wiebke Schüttig, Leonie Sundmacher This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7187871/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Hospitalizations resulting from ambulatory care sensitive conditions (ACSC) can be prevented or reduced through effective and timely ambulatory care. ACSC are used as an indicator of ambulatory care quality. As ACSC are influenced by contextual factors, such as disease prevalence and health system characteristics, they are usually assembled in national catalogues and updated within relevant time spans. In this study, we aim to update the 2015 catalogue of ACSC for Germany by Sundmacher et al. and validate our results in the context of previous research, taking into account relevant time trends and country-specific differences. Methods We use a structured methodology to derive the ACSC catalogue for Germany. First, we propose a list of potential diagnoses through ( 1 ) a literature review, ( 2 ) a data analysis on disease prevalence and regional variation for the German context and ( 3 ) a focus group meeting with patient representatives to incorporate patient opinion. Second, the proposed list is validated and expanded by a panel of medical experts in a structured consensus study. Discussion The ACSC catalogue for Germany will serve as a tool for informed decision making by providing the basis for assessing ambulatory care quality in the context of relevant time trends, identifying geographic areas with potential deficiencies in ambulatory care or comparing the overall state of ambulatory care in Germany with that in other countries. This information can be used to develop targeted improvement measures and, consequently, increase patient quality of life and reduce overall health care costs. Trial registration: The German clinical trial register number is DRKS00035331. It can be accessed under https://www.drks.de/DRKS00035331 . Date of trial registration is 7 February 2025. Ambulatory care sensitive conditions Ambulatory care sensitive hospitalizations Avoidable hospitalizations Delphi Group consensus Regional variation Focus group Germany Figures Figure 1 Background The ambulatory sector as first contact point for patients has a vital role in ensuring effective functioning of the overall health care system in Germany ( 1 ). Reliable indicators to measure the quality of ambulatory care are therefore essential to further develop and improve the health system and to adapt to changing conditions, as for instance an increase in health service use due to an ageing population ( 2 ). Ambulatory care sensitive hospitalizations (ACSH) are a frequently used indicator of the quality of ambulatory care. They are defined as hospitalizations that can be prevented or reduced by timely and effective ambulatory care. The concept rests on the assumption that a high number of ACSH might be associated with deficits in ambulatory care or a lack of access to the ambulatory sector ( 3 ). ACSH are usually differentiated by a number of measures to counteract them, i.e. effective management of chronic diseases, immunization against infectious diseases and effective treatment of acute conditions ( 1 , 3 , 4 ). In this context, it is important to distinguish ACSH from the concept of avoidable hospitalizations. The latter are not necessarily avoidable through ambulatory care but, for instance, through health political or other preventive measures. ACSH can therefore be considered a subgroup of avoidable hospitalizations ( 4 , 5 ). An advantage of ACSH compared with other quality indicators is the potential to use routine data and avoid additional documentation effort ( 6 ). Compared with other indicators, such as doctor–patient contacts, there is no need to assume that an increase in medical services use leads to enhanced quality of care ( 7 ). The expert counsel for evaluating the development of the German health system recommended ACSH specifically as a tool for quality measurement in a report to the German government in 2012 ( 8 ). An important criterion in studies assessing ACSH is the choice of conditions that can be considered ambulatory care sensitive (ambulatory care sensitive conditions, ACSC). To account for country-specific differences, it is common to develop national catalogues of ACSC. The reasons for this are deviations in disease prevalence, for example infectious diseases in Brazil that are not common in Germany ( 9 ) or differences in individual health systems, such as coding of diagnoses, doctor training, access to and limitations of the ambulatory sector, etc. ( 4 ). ACSC catalogues already exist for many countries, most notably Germany ( 1 ), Portugal ( 3 ), Brazil ( 9 ), Spain ( 10 ), the USA ( 11 ), Canada ( 12 ), Australia ( 13 ), the UK ( 14 ), Austria ( 15 ) and Sweden ( 16 ). The ACSC catalogue for Germany was first created in 2015 ( 1 ). Regular validation and updating of these catalogues is important to incorporate factors such as advancements in medical science and the resulting changes in disease prevalence and treatment modalities ( 3 ). We aim to update the 2015 ACSC catalogue using a similar methodological approach to allow for comparison of the results in the context of relevant time trends. Structured, multilevel consensus methods with medical experts from various fields are used to derive ACSC catalogues. It is common to first propose a list of diagnoses that is validated and expanded by medical experts in a second step. Literature often employs a number of criteria to identify ACSC based on Solberg et al. 1990 and Weissman et al. 1992 ( 17 , 18 ). The criteria are: (i) evidence in the literature that the condition is ambulatory care sensitive; (ii) relevance of the diagnosis for public health; (iii) consensus among experts and clinicians that the hospitalization is potentially avoidable by the effective and timely provision of ambulatory care; (iv) clarity regarding the definition and coding of the diagnosis and (v) the necessity of hospital treatment should the health problem related to the condition occur ( 1 , 10 , 19 ) The target of this study is to validate and update the existing ACSC catalogue for Germany involving specialists such as patient representatives and a panel of medical experts. Methods We will use a five-step methodology to derive the ACSC catalogue for Germany including ( 1 ) a systematic literature review, ( 2 ) data analysis, ( 3 ) a focus group meeting with patient representatives, ( 4 ) an expert consensus panel and ( 5 ) a comparison of our results with previous catalogues to assess relevant time trends or country-specific differences. Steps 1–3 are geared to proposing a list of ACSC that is then validated and expanded by medical experts in Step 4 ( 1 – 3 , 10 ). Figure 1 summarizes the process, links it to the criteria proposed by Solberg et al. and Weissman et al. and names external stakeholders (apart from the researchers) involved in the process. Step 1: Literature review We will conduct a systematic literature review targeted at identifying all newly published ACSC catalogues since the publication of the 2015 catalogue for Germany. We will perform the review in two screening stages. First, only the title and abstract of the identified studies will be independently reviewed by two researchers and assessed according to a number of inclusion and exclusion criteria. Second, the full texts of the remaining studies will be screened in the same manner. After each stage, we will calculate Cohen’s Kappa coefficient to determine interrater agreement between reviewers. Disagreements will be discussed and resolved between the two researchers. If no agreement can be found, a third person will be involved. We will use the search engines ‘PubMed’, ‘Web of Science’, ‘Scopus’ and ‘Cochrane’. The keywords ‘ambulatory care sensitive condition’, ‘primary care sensitive condition’, ‘ACSC’, ‘ambulatory care sensitive hospitalization’, ‘ACSH’, ‘primary care sensitive hospitalization’, ‘avoidable hospitalization’, ‘preventable hospitalization’, ‘avoidable admission’, ‘preventable admission’, ‘catalogue’ and ‘list’ will be used. To select relevant studies, we will apply the following inclusion and exclusion criteria: the focus must be on deriving an ACSC catalogue for adults (> 18 years); the study must use an empirical methodology, for instance expert involvement, and clear criteria to identify ACSCs. Articles that have been published in English or German up to the end of 2024 will be considered. We will use Citavi to combine search results and to manage duplicates. Thereafter, search results will be imported to Rayyan, a dedicated tool for performing systematic reviews, where the study selection process will be performed. Finally, we import included studies to Citavi for data extraction and results synthesis. The results of the systematic literature review are used to assess evidence in the literature that certain conditions are ambulatory care sensitive. If more than 50% of the studies identify the same ACSC, it is added to the proposed list of diagnoses. Diagnoses that are part of the existing catalogue for Germany are included in the proposed list in any case. Step 2: Data analysis Public health relevance In Step 2, we assess the public health relevance of the diagnoses identified in the literature review for the German context. A diagnosis is public health relevant if the hospitalization rate is at least 1/10,000 or if the condition constitutes a considerable health risk, for instance on account of resulting comorbidities or high resource usage ( 1 , 3 , 10 , 14 ). Therefore, we calculate hospitalization rates for each of the conditions identified in the literature review. Conditions that do not fulfil the prevalence criterion are included only if there is evidence in the literature that the condition is a substantial health risk for Germany. Regional variation in hospitalization rates To avoid overlooking emerging public health problems that have not yet been recognized in the literature, we additionally perform an analysis of the regional variation in the hospitalization rates of the most frequently coded diagnoses in 2023 ( 1 ). Our hypothesis is that high regional variation in hospitalization rates for certain diagnoses may indicate a sensitivity to differences in ambulatory care. To assess this, we obtain data on the number of hospitalizations for the most frequent three-digit ICD diagnoses at the municipality level from the German Federal Statistical Office. We will calculate the variances of hospitalization rates per county and diagnosis and compute the median per diagnosis. Subsequently, we will predict the expected variance per county via quantile regression techniques, taking into account the age and sex distribution of each county. We also compute the median of the expected variance. If the median variance of a diagnosis is significantly greater than expected, we add the respective diagnosis to the proposed list of ACSC. Step 3: Focus group with patient representatives Patient-centred care incorporates patient opinions and experiences when making or preparing health-related decisions ( 20 ). Therefore, we will invite patient representatives to a focus group meeting to discuss the concept of ACSC. A focus group is a moderated discussion on one specific topic. Compared with individual interviews, focus groups can be more informative as the researchers are able to observe participant interactions, for instance discussions of different views on the topic ( 21 ). At the beginning of the focus group meeting, participants will receive information on the concept of ACSC. Then they have the opportunity to discuss their views, potential observed reasons for ACSH and propose measures to reduce these hospitalizations. Additionally, they may also suggest conditions that should be included in the proposed list of ACSC. We will set up a heterogeneous focus group that includes patient representatives from different organizations with various backgrounds. All patient representatives provide their written consent to participate in the study. Step 4: Expert panel Expert panel members We consider four criteria when selecting the members of the expert panel: size of the panel, level of expertise, level of heterogeneity and level of interest ( 22 ). Size of the panel: Similar consensus studies have involved between 6 and 44 experts ( 1 – 3 , 10 , 14 , 23 – 25 ). According to a cross-disciplinary review of the Delphi method, at least 15–20 participants should finish all rounds of questionnaires to guarantee valid results ( 22 ). Consequently, we plan to recruit at least 25 participants to account for some experts sporadically not being able to complete all rounds of questionnaires. Level of expertise: We plan to recruit medical doctors who have successfully finished their training. Additionally, at least four nursing professionals will be part of the expert panel. Nursing professionals as the frontline care providers are an important factor in achieving excellent patient care ( 26 ). As considerable expertise is necessary to add value to the panel, participating nursing professionals should have at least 5 years’ experience in their position. Only medical experts who are currently working actively as either a medical doctor or a nursing professional will be included. Level of heterogeneity: We will diversify the panel according to practice setting, specialization and location of practice. Consequently, we plan to recruit an equal ratio of participants working in hospital and ambulatory settings. Here, it is important to have a clear definition of what is meant by ‘ambulatory setting’. Following Faisst and Sundmacher (2015), we include GPs and specialists working in an ambulatory practice. The care model, in which a panel of specialists treats patients with severe or rare diagnoses in an ambulatory setting, is not considered relevant to the ACSC concept ( 4 ). We will ensure that at least five GPs participate in the panel. Additionally, we will recruit at least one cardiologist, dermatologist, dentist, gynaecologist, neurologist, oncologist, orthopaedic specialist, psychiatrist or psychologist and a specialist in internal medicine. The majority of diseases mentioned in previous ACSC catalogues relate to one of these disciplines. Additionally, we will diversify according to rural and urban locations of practice using a 3:7 ratio for Germany, which we calculate on the basis of data from the National Association of Statutory Health Insurance (Kassenärztliche Bundesvereinigung) for the year 2023 ( 27 ). Level of interest: Personal interest in a study is an important motivator, and there is evidence for a positive correlation with quality of results ( 22 ). Consequently, we will favour participants who are actively engaged in academic collaboration. All panel members give their written consent to participate in the study. Expert consensus method The expert panel will evaluate whether hospitalizations for diagnoses, described in three- or four-digit ICD code and name of the disease, are potentially preventable through timely and effective ambulatory care. This will occur in a three-round structured consensus study according to the Delphi method. A Delphi study is characterized by a number of questionnaires (referred to as ‘rounds’) that iteratively lead to a consensus by building on the results of previous rounds. Additionally, participants receive individual feedback after each round that shows their answers in relation to group opinion ( 28 ). Participants in a Delphi study usually do not know each other's identities. This approach helps to prevent dominant group members from influencing the collective opinion ( 29 ). The definition of consensus is an important point to agree on before the initiation of a Delphi study. Similar studies employ consensus levels between 70% and 75% ( 1 – 3 ). To ultimately include or exclude diagnoses, we define that at least 70% of participants should agree or disagree. First Delphi round With the study invitation, all participants will receive detailed written information on the concept of ACSH, the study goals and their contribution as well as the Delphi process and the criteria for assessment. Before officially starting the survey, the first questionnaire will be piloted with two or three medical experts and their feedback included in the final version. We will employ digital questionnaires that are shared via email. In the first round of the Delphi study, the experts will again receive information about the ACSC concept and the criteria for assessment. Next, they evaluate whether hospitalizations caused by conditions proposed by the researchers are sensitive to ambulatory care [yes/no/only subcategories/no opinion]. Additionally, the experts can suggest potentially missing diagnoses through a free text field. Second Delphi round Before the second round, all experts receive individual feedback showing their answers and the overall group opinion for each question. In the second round, all diagnoses that did not reach the consensus level for inclusion or exclusion are re-evaluated. Additionally, all newly proposed diagnoses are assessed. For three-digit ICD codes that were assessed as ‘only subcategories are sensitive to ambulatory care’, all the respective four-digit ICD codes will be evaluated. Third Delphi round Before starting round 3, individual feedback is again shared with all participants. All diagnoses that reached the consensus level for agreement in rounds 1 or 2 will be re-evaluated in round 3. Those that again surpass the agreed consensus level are added to a preliminary ACSC catalogue for Germany. At this point, it is important to be aware that ACSH are usually not fully preventable. Many studies note a variety of confounding factors between ACSH and the quality of ambulatory care, such as patient characteristics, e.g. demographics, disease burden, socioeconomic factors, patient preferences and compliance, or factors related to the structure of the hospital sector, such as number of beds or distance to the next hospital ( 30 – 33 ). Therefore, in round 3, the experts are also asked to assess the degree of preventability of hospitalizations due to the identified ACSC. They also evaluate proposed medical measures geared to reducing ACSH, such as effective chronic disease management, immunization and timely treatment of acute conditions. Finally, they assess proposed systemic measures to improve the quality of ambulatory care, for instance improving access to ambulatory care, continuity and coordination of care and adapting financial incentives ( 34 , 35 ). To finalize the catalogue, a commission of two or three medical experts will assess the preliminary ACSC catalogue to ensure fulfilment of criteria (iv) clarity regarding the definition and coding of the diagnosis and (v) probability of hospital treatment should the health problem related to the condition occur. We will reformulate the original wording of criterion (v) from ‘necessity of hospital treatment’ to ‘probability of hospital treatment’. Researchers working on previous ACSC catalogues have experienced this criterion as being hard to fulfil for some diagnoses identified as ambulatory care sensitive by experts, for instance back pain, iron deficiency anaemia or sleep disorders ( 1 , 6 , 10 ). For such diagnoses, the necessity of hospital admission is heavily influenced by context, for instance patient clinical characteristics. Nevertheless, considering these diagnoses as part of a separate expanded ACSC catalogue can yield important insights into analyses of ambulatory care quality ( 10 ). Step 5: Comparison with previous catalogues Finally, the researchers will compare the final ACSC catalogue and the ensuing number of ACSH with previous work for Germany and other countries. This informs us of relevant time trends or country-specific differences that, ultimately, can be used to deduct learnings about ambulatory care quality and ways to improve it. Discussion Strengths and limitations In Germany, the majority of health issues are treated in an ambulatory setting. Measures of effective ambulatory care are positively correlated with variables indicating a healthier population. There is also evidence that effective ambulatory care has the potential to reduce overall health system costs by avoiding certain hospital admissions ( 10 , 36 ). The proposed ACSC catalogue for Germany provides a comprehensive and up-to-date basis for identifying the conditions leading to hospital admissions that could have been prevented by timely and effective ambulatory care. Additionally, we estimate the degree of preventability for each condition and propose strategies to reduce ACSH. Nevertheless, several limitations need to be considered. The relationship between ACSH and ambulatory care quality is confounded by various factors, such as patient-level and environmental influences, which are difficult to control for ( 36 , 37 ). We recommend using ACSH together with other quality indicators to assess patient outcomes or to identify smaller geographic areas with shortcomings in ambulatory care ( 1 ). Furthermore, the Delphi method has inherent limitations. First, the methodology does not guarantee that one definitive ACSC catalogue for Germany has been found. The results always depend to a certain degree on the composition of the expert panel. We alleviate this caveat by assembling a heterogeneous panel of experts consisting of doctors with different medical backgrounds and nursing professionals. The preselection of diagnoses through a systematic literature review and data analyses further objectifies the methodology. Second, the Delphi method has been criticized because of the individual feedback mechanism targeted at converging participant opinions ( 29 , 38 ). This, however, is the case for all consensus methods. For example, in the nominal group technique, face-to-face discussions are used to align participant opinions ( 39 ). Furthermore, consensus methods are the standard approach for developing ACSC catalogues ( 1 – 3 , 10 , 14 , 23 – 25 ). As our goal is to validate and compare our results with those of previous studies, such as the 2015 ACSC catalogue for Germany, it is logical to use a similar methodological framework. Implications for practice and research Ultimately, the ACSC catalogue contributes to informed decision making by providing the basis for assessing ambulatory care quality in the context of relevant time trends, identifying geographic areas with potential deficiencies in ambulatory care or comparing the overall state of ambulatory care in Germany with that in other countries. This information can be used to develop targeted improvement measures and, consequently, increase patient quality of life and reduce overall health care costs. Abbreviations ACSC ambulatory care sensitive conditions ACSH ambulatory care sensitive hospitalizations GP general practitioner TUM Technical University of Munich Declarations Ethics approval and consent to participate This protocol was reviewed and approved by the ethics committee of the Technical University of Munich (granted 2024/12/02), in accordance with the Declaration of Helsinki or comparable ethical standards. All changes in the protocol throughout the trial must be approved by the ethics committee. All participants give their written consent to participate in the study. Consent for publication With the study results, only aggregated results of the focus group meeting and the expert panel that cannot be traced back to individual participants will be published. Availability of data and materials The datasets generated during the current study are not publicly available as they contain the individual views and answers of the survey respondents. Competing interests The authors declare that they do not have competing interests. Funding The study is fully funded by internal funds of the Department for Health Economics at the Technical University of Munich. Authors’ contribution LS, WS and GW planned and designed the study. GW drafted the manuscript together with WS and LS. All authors reviewed and edited the original manuscript. All authors provided input, read and approved the final manuscript. Acknowledgements Not applicable Authors’ information All authors work at the Technical University of Munich (TUM). References Sundmacher L, Fischbach D, Schuettig W, Naumann C, Augustin U, Faisst C. Which hospitalizations are ambulatory care-sensitive, to what degree, and how could the rates be reduced? Results of a group consensus study in Germany. Health Policy 2015; 119(11):1415–23. Wang J, Xu DR, Zhang Y, Fu H, Wang S, Ju K et al. Development of China's list of ambulatory care sensitive conditions (ACSCs): a study protocol. 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The impact of ambulatory care spending, continuity and processes of care on ambulatory care sensitive hospitalizations. Eur J Health Econ 2022; 23(8):1329–40. van Loenen T, van den Berg MJ, Westert GP, Faber MJ. Organizational aspects of primary care related to avoidable hospitalization: a systematic review. Fam Pract 2014; 31(5):502–16. Trachtenberg AJ, Dik N, Chateau D, Katz A. Inequities in ambulatory care and the relationship between socioeconomic status and respiratory hospitalizations: a population-based study of a Canadian city. Ann Fam Med 2014; 12(5):402–7. Scheibe M, Skutsch M, Schofer J. IV. C. Experiments in Delphi methodology. The Delphi method: Techn Appl 2002:257–81. Fink A, Kosecoff J, Chassin M, Brook RH. Consensus methods: characteristics and guidelines for use. Am J Public Health 1984; 74(9):979–83. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7187871","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Study protocol","associatedPublications":[],"authors":[{"id":492293983,"identity":"a55d6296-3ca3-400e-a386-85da59e93997","order_by":0,"name":"Gina Wittlinger","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7UlEQVRIiWNgGAWjYDACZjApwcDAztgAYsmB+TxEaJHgYYZoMeYhqAUKgFogjMQeQlrk3XkPfmBss6izZ2Zue/il4l76fonsBIY3Fbi1GB7mS5ZgbAM7rN1Y5kxxbo9E7gbGOWfwaGnmMZBg3AbW0iYt2ZYA1sLM24ZXi/EPhJZ/Cek8YC3/8PiFmccMbovkx4aEBIiWBtxaDIBaLBL/SUj2HAbawnAswbDnzNsNB+ccw2NL/xnjGx/O1PGzt7c/k/xRkyDP3p678cGbGjy2HAASCVAOMyw6DuDWALQF2dGMP/ApHQWjYBSMghELAD44RPQAYBLoAAAAAElFTkSuQmCC","orcid":"","institution":"Technical University of Munich","correspondingAuthor":true,"prefix":"","firstName":"Gina","middleName":"","lastName":"Wittlinger","suffix":""},{"id":492293984,"identity":"2043d416-b833-4def-806b-837c672622a2","order_by":1,"name":"Wiebke Schüttig","email":"","orcid":"","institution":"Technical University of Munich","correspondingAuthor":false,"prefix":"","firstName":"Wiebke","middleName":"","lastName":"Schüttig","suffix":""},{"id":492293985,"identity":"9d1dc9c5-0a53-483e-91a3-cd87f2dca688","order_by":2,"name":"Leonie Sundmacher","email":"","orcid":"","institution":"Technical University of Munich","correspondingAuthor":false,"prefix":"","firstName":"Leonie","middleName":"","lastName":"Sundmacher","suffix":""}],"badges":[],"createdAt":"2025-07-22 14:08:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7187871/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7187871/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87905090,"identity":"7fd7ef78-a38d-4b38-9f0f-c6ffaff8335c","added_by":"auto","created_at":"2025-07-30 08:43:15","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":243773,"visible":true,"origin":"","legend":"\u003cp\u003eProcess for deriving the ACSC catalogue for Germany\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7187871/v1/315a4bc06edbcd8610ff5b65.png"},{"id":87931453,"identity":"14c44beb-03f8-4de5-9905-23d130458031","added_by":"auto","created_at":"2025-07-30 13:39:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":699053,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7187871/v1/fedd0f47-43f0-4dd6-ad3f-e196f47388c1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Catalogue of ambulatory care sensitive conditions (ACSC) for Germany 2025: protocol of a group consensus study","fulltext":[{"header":"Background","content":"\u003cp\u003eThe ambulatory sector as first contact point for patients has a vital role in ensuring effective functioning of the overall health care system in Germany (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Reliable indicators to measure the quality of ambulatory care are therefore essential to further develop and improve the health system and to adapt to changing conditions, as for instance an increase in health service use due to an ageing population (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAmbulatory care sensitive hospitalizations (ACSH) are a frequently used indicator of the quality of ambulatory care. They are defined as hospitalizations that can be prevented or reduced by timely and effective ambulatory care. The concept rests on the assumption that a high number of ACSH might be associated with deficits in ambulatory care or a lack of access to the ambulatory sector (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). ACSH are usually differentiated by a number of measures to counteract them, i.e. effective management of chronic diseases, immunization against infectious diseases and effective treatment of acute conditions (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). In this context, it is important to distinguish ACSH from the concept of avoidable hospitalizations. The latter are not necessarily avoidable through ambulatory care but, for instance, through health political or other preventive measures. ACSH can therefore be considered a subgroup of avoidable hospitalizations (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAn advantage of ACSH compared with other quality indicators is the potential to use routine data and avoid additional documentation effort (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Compared with other indicators, such as doctor–patient contacts, there is no need to assume that an increase in medical services use leads to enhanced quality of care (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). The expert counsel for evaluating the development of the German health system recommended ACSH specifically as a tool for quality measurement in a report to the German government in 2012 (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAn important criterion in studies assessing ACSH is the choice of conditions that can be considered ambulatory care sensitive (ambulatory care sensitive conditions, ACSC). To account for country-specific differences, it is common to develop national catalogues of ACSC. The reasons for this are deviations in disease prevalence, for example infectious diseases in Brazil that are not common in Germany (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) or differences in individual health systems, such as coding of diagnoses, doctor training, access to and limitations of the ambulatory sector, etc. (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). ACSC catalogues already exist for many countries, most notably Germany (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e), Portugal (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e), Brazil (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e), Spain (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e), the USA (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e), Canada (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e), Australia (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e), the UK (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e), Austria (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) and Sweden (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe ACSC catalogue for Germany was first created in 2015 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Regular validation and updating of these catalogues is important to incorporate factors such as advancements in medical science and the resulting changes in disease prevalence and treatment modalities (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). We aim to update the 2015 ACSC catalogue using a similar methodological approach to allow for comparison of the results in the context of relevant time trends.\u003c/p\u003e\u003cp\u003eStructured, multilevel consensus methods with medical experts from various fields are used to derive ACSC catalogues. It is common to first propose a list of diagnoses that is validated and expanded by medical experts in a second step. Literature often employs a number of criteria to identify ACSC based on Solberg et al. 1990 and Weissman et al. 1992 (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). The criteria are: (i) evidence in the literature that the condition is ambulatory care sensitive; (ii) relevance of the diagnosis for public health; (iii) consensus among experts and clinicians that the hospitalization is potentially avoidable by the effective and timely provision of ambulatory care; (iv) clarity regarding the definition and coding of the diagnosis and (v) the necessity of hospital treatment should the health problem related to the condition occur (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e)\u003c/p\u003e\u003cp\u003eThe target of this study is to validate and update the existing ACSC catalogue for Germany involving specialists such as patient representatives and a panel of medical experts.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eWe will use a five-step methodology to derive the ACSC catalogue for Germany including (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) a systematic literature review, (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) data analysis, (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) a focus group meeting with patient representatives, (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) an expert consensus panel and (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e) a comparison of our results with previous catalogues to assess relevant time trends or country-specific differences. Steps 1–3 are geared to proposing a list of ACSC that is then validated and expanded by medical experts in Step 4 (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e–\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e summarizes the process, links it to the criteria proposed by Solberg et al. and Weissman et al. and names external stakeholders (apart from the researchers) involved in the process.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStep 1: Literature review\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWe will conduct a systematic literature review targeted at identifying all newly published ACSC catalogues since the publication of the 2015 catalogue for Germany. We will perform the review in two screening stages. First, only the title and abstract of the identified studies will be independently reviewed by two researchers and assessed according to a number of inclusion and exclusion criteria. Second, the full texts of the remaining studies will be screened in the same manner. After each stage, we will calculate Cohen’s Kappa coefficient to determine interrater agreement between reviewers. Disagreements will be discussed and resolved between the two researchers. If no agreement can be found, a third person will be involved.\u003c/p\u003e\u003cp\u003eWe will use the search engines ‘PubMed’, ‘Web of Science’, ‘Scopus’ and ‘Cochrane’. The keywords ‘ambulatory care sensitive condition’, ‘primary care sensitive condition’, ‘ACSC’, ‘ambulatory care sensitive hospitalization’, ‘ACSH’, ‘primary care sensitive hospitalization’, ‘avoidable hospitalization’, ‘preventable hospitalization’, ‘avoidable admission’, ‘preventable admission’, ‘catalogue’ and ‘list’ will be used. To select relevant studies, we will apply the following inclusion and exclusion criteria: the focus must be on deriving an ACSC catalogue for adults (\u0026gt; 18 years); the study must use an empirical methodology, for instance expert involvement, and clear criteria to identify ACSCs. Articles that have been published in English or German up to the end of 2024 will be considered.\u003c/p\u003e\u003cp\u003eWe will use Citavi to combine search results and to manage duplicates. Thereafter, search results will be imported to Rayyan, a dedicated tool for performing systematic reviews, where the study selection process will be performed. Finally, we import included studies to Citavi for data extraction and results synthesis.\u003c/p\u003e\u003cp\u003eThe results of the systematic literature review are used to assess evidence in the literature that certain conditions are ambulatory care sensitive. If more than 50% of the studies identify the same ACSC, it is added to the proposed list of diagnoses. Diagnoses that are part of the existing catalogue for Germany are included in the proposed list in any case.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStep 2: Data analysis\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003ePublic health relevance\u003c/em\u003e\u003c/p\u003e\u003cp\u003eIn Step 2, we assess the public health relevance of the diagnoses identified in the literature review for the German context. A diagnosis is public health relevant if the hospitalization rate is at least 1/10,000 or if the condition constitutes a considerable health risk, for instance on account of resulting comorbidities or high resource usage (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). Therefore, we calculate hospitalization rates for each of the conditions identified in the literature review. Conditions that do not fulfil the prevalence criterion are included only if there is evidence in the literature that the condition is a substantial health risk for Germany.\u003c/p\u003e\u003cp\u003e\u003cem\u003eRegional variation in hospitalization rates\u003c/em\u003e\u003c/p\u003e\u003cp\u003eTo avoid overlooking emerging public health problems that have not yet been recognized in the literature, we additionally perform an analysis of the regional variation in the hospitalization rates of the most frequently coded diagnoses in 2023 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Our hypothesis is that high regional variation in hospitalization rates for certain diagnoses may indicate a sensitivity to differences in ambulatory care. To assess this, we obtain data on the number of hospitalizations for the most frequent three-digit ICD diagnoses at the municipality level from the German Federal Statistical Office. We will calculate the variances of hospitalization rates per county and diagnosis and compute the median per diagnosis. Subsequently, we will predict the expected variance per county via quantile regression techniques, taking into account the age and sex distribution of each county. We also compute the median of the expected variance. If the median variance of a diagnosis is significantly greater than expected, we add the respective diagnosis to the proposed list of ACSC.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStep 3: Focus group with patient representatives\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePatient-centred care incorporates patient opinions and experiences when making or preparing health-related decisions (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). Therefore, we will invite patient representatives to a focus group meeting to discuss the concept of ACSC. A focus group is a moderated discussion on one specific topic. Compared with individual interviews, focus groups can be more informative as the researchers are able to observe participant interactions, for instance discussions of different views on the topic (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). At the beginning of the focus group meeting, participants will receive information on the concept of ACSC. Then they have the opportunity to discuss their views, potential observed reasons for ACSH and propose measures to reduce these hospitalizations. Additionally, they may also suggest conditions that should be included in the proposed list of ACSC.\u003c/p\u003e\u003cp\u003eWe will set up a heterogeneous focus group that includes patient representatives from different organizations with various backgrounds. All patient representatives provide their written consent to participate in the study.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStep 4: Expert panel\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eExpert panel members\u003c/em\u003e\u003c/p\u003e\u003cp\u003eWe consider four criteria when selecting the members of the expert panel: size of the panel, level of expertise, level of heterogeneity and level of interest (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eSize of the panel: Similar consensus studies have involved between 6 and 44 experts (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e–\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e–\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e). According to a cross-disciplinary review of the Delphi method, at least 15–20 participants should finish all rounds of questionnaires to guarantee valid results (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). Consequently, we plan to recruit at least 25 participants to account for some experts sporadically not being able to complete all rounds of questionnaires.\u003c/p\u003e\u003cp\u003eLevel of expertise: We plan to recruit medical doctors who have successfully finished their training. Additionally, at least four nursing professionals will be part of the expert panel. Nursing professionals as the frontline care providers are an important factor in achieving excellent patient care (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e). As considerable expertise is necessary to add value to the panel, participating nursing professionals should have at least 5 years’ experience in their position. Only medical experts who are currently working actively as either a medical doctor or a nursing professional will be included.\u003c/p\u003e\u003cp\u003eLevel of heterogeneity: We will diversify the panel according to practice setting, specialization and location of practice. Consequently, we plan to recruit an equal ratio of participants working in hospital and ambulatory settings. Here, it is important to have a clear definition of what is meant by ‘ambulatory setting’. Following Faisst and Sundmacher (2015), we include GPs and specialists working in an ambulatory practice. The care model, in which a panel of specialists treats patients with severe or rare diagnoses in an ambulatory setting, is not considered relevant to the ACSC concept (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). We will ensure that at least five GPs participate in the panel. Additionally, we will recruit at least one cardiologist, dermatologist, dentist, gynaecologist, neurologist, oncologist, orthopaedic specialist, psychiatrist or psychologist and a specialist in internal medicine. The majority of diseases mentioned in previous ACSC catalogues relate to one of these disciplines. Additionally, we will diversify according to rural and urban locations of practice using a 3:7 ratio for Germany, which we calculate on the basis of data from the National Association of Statutory Health Insurance (Kassenärztliche Bundesvereinigung) for the year 2023 (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eLevel of interest: Personal interest in a study is an important motivator, and there is evidence for a positive correlation with quality of results (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). Consequently, we will favour participants who are actively engaged in academic collaboration. All panel members give their written consent to participate in the study.\u003c/p\u003e\u003cp\u003e\u003cem\u003eExpert consensus method\u003c/em\u003e\u003c/p\u003e\u003cp\u003eThe expert panel will evaluate whether hospitalizations for diagnoses, described in three- or four-digit ICD code and name of the disease, are potentially preventable through timely and effective ambulatory care. This will occur in a three-round structured consensus study according to the Delphi method.\u003c/p\u003e\u003cp\u003eA Delphi study is characterized by a number of questionnaires (referred to as ‘rounds’) that iteratively lead to a consensus by building on the results of previous rounds. Additionally, participants receive individual feedback after each round that shows their answers in relation to group opinion (\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e). Participants in a Delphi study usually do not know each other's identities. This approach helps to prevent dominant group members from influencing the collective opinion (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e). The definition of consensus is an important point to agree on before the initiation of a Delphi study. Similar studies employ consensus levels between 70% and 75% (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e–\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). To ultimately include or exclude diagnoses, we define that at least 70% of participants should agree or disagree.\u003c/p\u003e\u003cp\u003e\u003cem\u003eFirst Delphi round\u003c/em\u003e\u003c/p\u003e\u003cp\u003eWith the study invitation, all participants will receive detailed written information on the concept of ACSH, the study goals and their contribution as well as the Delphi process and the criteria for assessment. Before officially starting the survey, the first questionnaire will be piloted with two or three medical experts and their feedback included in the final version. We will employ digital questionnaires that are shared via email.\u003c/p\u003e\u003cp\u003eIn the first round of the Delphi study, the experts will again receive information about the ACSC concept and the criteria for assessment. Next, they evaluate whether hospitalizations caused by conditions proposed by the researchers are sensitive to ambulatory care [yes/no/only subcategories/no opinion]. Additionally, the experts can suggest potentially missing diagnoses through a free text field.\u003c/p\u003e\u003cp\u003e\u003cem\u003eSecond Delphi round\u003c/em\u003e\u003c/p\u003e\u003cp\u003eBefore the second round, all experts receive individual feedback showing their answers and the overall group opinion for each question. In the second round, all diagnoses that did not reach the consensus level for inclusion or exclusion are re-evaluated. Additionally, all newly proposed diagnoses are assessed. For three-digit ICD codes that were assessed as ‘only subcategories are sensitive to ambulatory care’, all the respective four-digit ICD codes will be evaluated.\u003c/p\u003e\u003cp\u003e\u003cem\u003eThird Delphi round\u003c/em\u003e\u003c/p\u003e\u003cp\u003eBefore starting round 3, individual feedback is again shared with all participants. All diagnoses that reached the consensus level for agreement in rounds 1 or 2 will be re-evaluated in round 3. Those that again surpass the agreed consensus level are added to a preliminary ACSC catalogue for Germany.\u003c/p\u003e\u003cp\u003eAt this point, it is important to be aware that ACSH are usually not fully preventable. Many studies note a variety of confounding factors between ACSH and the quality of ambulatory care, such as patient characteristics, e.g. demographics, disease burden, socioeconomic factors, patient preferences and compliance, or factors related to the structure of the hospital sector, such as number of beds or distance to the next hospital (\u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e–\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eTherefore, in round 3, the experts are also asked to assess the degree of preventability of hospitalizations due to the identified ACSC. They also evaluate proposed medical measures geared to reducing ACSH, such as effective chronic disease management, immunization and timely treatment of acute conditions. Finally, they assess proposed systemic measures to improve the quality of ambulatory care, for instance improving access to ambulatory care, continuity and coordination of care and adapting financial incentives (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eTo finalize the catalogue, a commission of two or three medical experts will assess the preliminary ACSC catalogue to ensure fulfilment of criteria (iv) clarity regarding the definition and coding of the diagnosis and (v) probability of hospital treatment should the health problem related to the condition occur. We will reformulate the original wording of criterion (v) from ‘necessity of hospital treatment’ to ‘probability of hospital treatment’. Researchers working on previous ACSC catalogues have experienced this criterion as being hard to fulfil for some diagnoses identified as ambulatory care sensitive by experts, for instance back pain, iron deficiency anaemia or sleep disorders (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). For such diagnoses, the necessity of hospital admission is heavily influenced by context, for instance patient clinical characteristics. Nevertheless, considering these diagnoses as part of a separate expanded ACSC catalogue can yield important insights into analyses of ambulatory care quality (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cb\u003eStep 5: Comparison with previous catalogues\u003c/b\u003e\u003c/p\u003e\u003cp\u003eFinally, the researchers will compare the final ACSC catalogue and the ensuing number of ACSH with previous work for Germany and other countries. This informs us of relevant time trends or country-specific differences that, ultimately, can be used to deduct learnings about ambulatory care quality and ways to improve it.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003e\u003cb\u003eStrengths and limitations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIn Germany, the majority of health issues are treated in an ambulatory setting. Measures of effective ambulatory care are positively correlated with variables indicating a healthier population. There is also evidence that effective ambulatory care has the potential to reduce overall health system costs by avoiding certain hospital admissions (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe proposed ACSC catalogue for Germany provides a comprehensive and up-to-date basis for identifying the conditions leading to hospital admissions that could have been prevented by timely and effective ambulatory care. Additionally, we estimate the degree of preventability for each condition and propose strategies to reduce ACSH.\u003c/p\u003e\u003cp\u003eNevertheless, several limitations need to be considered. The relationship between ACSH and ambulatory care quality is confounded by various factors, such as patient-level and environmental influences, which are difficult to control for (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e). We recommend using ACSH together with other quality indicators to assess patient outcomes or to identify smaller geographic areas with shortcomings in ambulatory care (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eFurthermore, the Delphi method has inherent limitations. First, the methodology does not guarantee that one definitive ACSC catalogue for Germany has been found. The results always depend to a certain degree on the composition of the expert panel. We alleviate this caveat by assembling a heterogeneous panel of experts consisting of doctors with different medical backgrounds and nursing professionals. The preselection of diagnoses through a systematic literature review and data analyses further objectifies the methodology. Second, the Delphi method has been criticized because of the individual feedback mechanism targeted at converging participant opinions (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e). This, however, is the case for all consensus methods. For example, in the nominal group technique, face-to-face discussions are used to align participant opinions (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e). Furthermore, consensus methods are the standard approach for developing ACSC catalogues (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e). As our goal is to validate and compare our results with those of previous studies, such as the 2015 ACSC catalogue for Germany, it is logical to use a similar methodological framework.\u003c/p\u003e\u003cp\u003e\u003cb\u003eImplications for practice and research\u003c/b\u003e\u003c/p\u003e\u003cp\u003eUltimately, the ACSC catalogue contributes to informed decision making by providing the basis for assessing ambulatory care quality in the context of relevant time trends, identifying geographic areas with potential deficiencies in ambulatory care or comparing the overall state of ambulatory care in Germany with that in other countries. This information can be used to develop targeted improvement measures and, consequently, increase patient quality of life and reduce overall health care costs.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eACSC ambulatory care sensitive conditions\u003c/p\u003e\n\u003cp\u003eACSH ambulatory care sensitive hospitalizations\u003c/p\u003e\n\u003cp\u003eGP general practitioner\u003c/p\u003e\n\u003cp\u003eTUM Technical University of Munich\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cem\u003eEthics approval and consent to participate\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThis protocol was reviewed and approved by the ethics committee of the Technical University of Munich (granted 2024/12/02),\u0026nbsp;in accordance with the Declaration of Helsinki or comparable ethical standards. All changes in the protocol throughout the trial must be approved by the ethics committee. All participants give their written consent to participate in the study.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConsent for publication\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWith the study results, only aggregated results of the focus group meeting and the expert panel that cannot be traced back to individual participants will be published.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAvailability of data and materials\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during the current study are not publicly available as they contain the individual views and answers of the survey respondents. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCompeting interests\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they do not have competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFunding\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe study is fully funded by internal funds of the Department for Health Economics at the Technical University of Munich.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAuthors\u0026rsquo; contribution\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eLS, WS and GW planned and designed the study. GW drafted the manuscript together with WS and LS. All authors reviewed and edited the original manuscript. All authors provided input, read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAcknowledgements\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAuthors\u0026rsquo; information\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAll authors work at the Technical University of Munich (TUM).\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSundmacher L, Fischbach D, Schuettig W, Naumann C, Augustin U, Faisst C. Which hospitalizations are ambulatory care-sensitive, to what degree, and how could the rates be reduced? Results of a group consensus study in Germany. Health Policy 2015; 119(11):1415\u0026ndash;23.\u003c/li\u003e\n\u003cli\u003eWang J, Xu DR, Zhang Y, Fu H, Wang S, Ju K et al. Development of China\u0026apos;s list of ambulatory care sensitive conditions (ACSCs): a study protocol. Glob Health Res Policy 2024; 9(1):11.\u003c/li\u003e\n\u003cli\u003eSarmento J, Rocha JVM, Santana R. Defining ambulatory care sensitive conditions for adults in Portugal. BMC Health Serv Res 2020; 20(1):754.\u003c/li\u003e\n\u003cli\u003eFaisst C, Sundmacher L. Ambulant-sensitive Krankenhausf\u0026auml;lle: Eine inter-nationale \u0026Uuml;bersicht mit Schlussfolgerungen f\u0026uuml;r einen deutschen Katalog. Gesundheitswesen 2015; 77(3):168\u0026ndash;77.\u003c/li\u003e\n\u003cli\u003eMinistry of Health New Zealand. Indicator of potentially avoidable hospitalizations for the Child and Youth Wellbeing Strategy: A brief report on methodology; 2020 [cited 2025 Feb 7]. Available from: URL: https://www.health.govt.nz/publications/indicator-of-potentially-avoidable-hospitalizations-for-the-child-and-youth-wellbeing-strategy-a.\u003c/li\u003e\n\u003cli\u003eBurgdorf F, Sundmacher L. Potentially avoidable hospital admissions in Germany. Deutsches \u0026Auml;rzteblatt Int 2014; 111(13):215\u0026ndash;23.\u003c/li\u003e\n\u003cli\u003eKlauber J, Geraedts M, Friedrich J, Wasem J, editors. Krankenhaus-Report: Regionalit\u0026auml;t. Stuttgart: Schattauer; 2012.\u003c/li\u003e\n\u003cli\u003eSachverst\u0026auml;ndigenrat zur Begutachtung der Entwicklung im Gesundheitswesen. Wettbewerb an der Schnittstelle Wettbewerb an der Schnittstelle zwischen ambulanter und station\u0026auml;rer Gesundheitsversorgung: Sondergutachten 2012 des Sachverst\u0026auml;ndigenrates zur Begutachtung der Entwicklung im Gesundheitswesen: Deutscher Bundestag; 2012 [cited 2024 Sep 16]. Available from: URL: https://dserver.bundestag.de/btd/17/103/1710323.pdf.\u003c/li\u003e\n\u003cli\u003eAlfradique ME, Bonolo PdF, Dourado I, Lima-Costa MF, Macinko J, Mendon\u0026ccedil;a CS et al. 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Available from: URL: https://publications.gc.ca/collections/collection_2013/icis-cihi/H115-67-2013-eng.pdf.\u003c/li\u003e\n\u003cli\u003eAustralian Institute of Health and Welfare. Atlas of avoidable hospitalizations in Australia: ambulatory care-sensitive conditions. Canberra: AIHW; 2007 [cited 2025 Feb 7]. Available from: URL: https://www.aihw.gov.au/reports/hospitals/atlas-avoidable-hospitalizations-australia.\u003c/li\u003e\n\u003cli\u003ePurdy S, Griffin T, Salisbury C, Sharp D. Ambulatory care sensitive conditions: terminology and disease coding need to be more specific to aid policy makers and clinicians. Public Health 2009; 123(2):169\u0026ndash;73.\u003c/li\u003e\n\u003cli\u003eCzypionka T, R\u0026ouml;hrling G, Ulinski S. Ambulatory care sensitive conditions (ACSC): Einflussfaktoren international und in \u0026Ouml;sterreich: Studie im Auftrag des Hauptverbands der \u0026ouml;sterreichischen Sozialversicherungstr\u0026auml;ger 2014 [cited 2025 Feb 7]. Available from: URL: https://www.sozialversicherung.gv.at/cdscontent/?contentid=10007.844125\u0026amp;portal=svportal.\u003c/li\u003e\n\u003cli\u003eSwedish Association of Local Authorities and Regions (SALAR). Quality and efficiency in Swedish health care; 2008 [cited 2025 Feb 7]. Available from: URL: https://skr.se/download/18.45167e4317e2b341b24ad7ba/1642684549781/7164-452-7.pdf.\u003c/li\u003e\n\u003cli\u003eSolberg LI, Peterson KE, Ellis RW, Romness K, Rohrenbach E, Thell T et al. The Minnesota project: a focused approach to ambulatory quality assessment. Inquiry 1990; 27(4):359\u0026ndash;67.\u003c/li\u003e\n\u003cli\u003eWeissman JS, Gatsonis C, Epstein AM. Rates of avoidable hospitalization by insurance status in Massachusetts and Maryland. JAMA 1992; 268(17):2388\u0026ndash;94.\u003c/li\u003e\n\u003cli\u003eSarmento J, Alves C, Oliveira P, Sebasti\u0026atilde;o R, Santana R. Characterization and evolution of avoidable admissions in Portugal: The impact of two methodologic approaches. Acta Med Port 2020; 28(5):590\u0026ndash;600.\u003c/li\u003e\n\u003cli\u003eSacrist\u0026aacute;n JA, Aguar\u0026oacute;n A, Avenda\u0026ntilde;o-Sol\u0026aacute; C, Garrido P, Carri\u0026oacute;n J, Guti\u0026eacute;rrez A et al. Patient involvement in clinical research: why, when, and how. Patient Preference Adherence 2016:631\u0026ndash;40.\u003c/li\u003e\n\u003cli\u003eGreen J, Thorogood N. Qualitative Methods for Health Research. London: Sage Publications; 2004.\u003c/li\u003e\n\u003cli\u003eDaniel Beiderbeck, Nicolas Frevel, Heiko A. von der Gracht, Sascha L. Schmidt, Vera M. Schweitzer. Preparing, conducting, and analyzing Delphi surveys: Cross-disciplinary practices, new directions, and advancements. MethodsX 2021; 8:1\u0026ndash;20.\u003c/li\u003e\n\u003cli\u003eBillings J, Zeitel L, Lukomnik J, Carey T, Blank A, Newman L. Impact of socioeconomic status on hospital resource use in New York City. Health Affairs (Project Hope) 1993; 12:162\u0026ndash;73.\u003c/li\u003e\n\u003cli\u003eBrown AD, Goldacre MJ, Hicks N, Rourke JT, McMurtry RY, Brown JD et al. Hospitalization for ambulatory care-sensitive conditions: A method for comparative access and quality studies using routinely collected statistics. Can J Pub Health 2001; 92(2):155\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eAnderson P, Craig E, Jackson G, Jackson C. Developing a tool to monitor potentially avoidable and ambulatory care sensitive hospitalizations in New Zealand children. NZ Med J 2012; 125(1366).\u003c/li\u003e\n\u003cli\u003eHickey JV, Giardino ER. The role of the nurse in quality improvement and patient safety. J Neurol Neurosurg Nurs 2019; 8(1):30\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eKassen\u0026auml;rztliche Bundesvereinigung. Gesundheitsdaten: Regionale Verteilung der \u0026Auml;rztinnen und \u0026Auml;rzte in der vertrags\u0026auml;rztlichen Versorgung; 2024 [cited 2024 Oct 18]. Available from: URL: https://gesundheitsdaten.kbv.de/cms/html/16402.php.\u003c/li\u003e\n\u003cli\u003eHasson F, Keeney S, McKenna H. Research guidelines for the Delphi survey technique. J Adv Nurs 2000; 32(4):1008\u0026ndash;15.\u003c/li\u003e\n\u003cli\u003eGoodman CM. The Delphi technique: a critique. J Adv Nurs 1987; 12(6):729\u0026ndash;34.\u003c/li\u003e\n\u003cli\u003eBarnett R, Malcolm L. Practice and ethnic variations in avoidable hospital admission rates in Christchurch, New Zealand. Health \u0026amp; Place 2010; 16(2):199\u0026ndash;208.\u003c/li\u003e\n\u003cli\u003eAnsari Z, Laditka JN, Laditka SB. Access to health care and hospitalization for ambulatory care sensitive conditions. Med Care Res Rev 2006; 63(6):719\u0026ndash;41.\u003c/li\u003e\n\u003cli\u003eFreund T, Campbell SM, Geissler S, Kunz CU, Mahler C, Peters-Klimm F et al. Strategies for reducing potentially avoidable hospitalizations for ambulatory care-sensitive conditions. Ann Fam Med 2013; 11(4):363\u0026ndash;70.\u003c/li\u003e\n\u003cli\u003eSundmacher L, Kopetsch T. The impact of office-based care on hospitalizations for ambulatory care sensitive conditions. Eur J Health Econ 2015; 16:365\u0026ndash;75.\u003c/li\u003e\n\u003cli\u003eLize Duminy, Vanessa Ress, Eva-Maria Wild. Complex community health and social care interventions \u0026ndash; Which features lead to reductions in hospitalizations for ambulatory care sensitive conditions? A systematic literature review. Health Policy 2022; 126(12):1206\u0026ndash;25.\u003c/li\u003e\n\u003cli\u003eSchuettig W, Sundmacher L. The impact of ambulatory care spending, continuity and processes of care on ambulatory care sensitive hospitalizations. Eur J Health Econ 2022; 23(8):1329\u0026ndash;40.\u003c/li\u003e\n\u003cli\u003evan Loenen T, van den Berg MJ, Westert GP, Faber MJ. Organizational aspects of primary care related to avoidable hospitalization: a systematic review. Fam Pract 2014; 31(5):502\u0026ndash;16.\u003c/li\u003e\n\u003cli\u003eTrachtenberg AJ, Dik N, Chateau D, Katz A. Inequities in ambulatory care and the relationship between socioeconomic status and respiratory hospitalizations: a population-based study of a Canadian city. Ann Fam Med 2014; 12(5):402\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eScheibe M, Skutsch M, Schofer J. IV. C. Experiments in Delphi methodology. The Delphi method: Techn Appl 2002:257\u0026ndash;81.\u003c/li\u003e\n\u003cli\u003eFink A, Kosecoff J, Chassin M, Brook RH. Consensus methods: characteristics and guidelines for use. Am J Public Health 1984; 74(9):979\u0026ndash;83.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Ambulatory care sensitive conditions, Ambulatory care sensitive hospitalizations, Avoidable hospitalizations, Delphi, Group consensus, Regional variation, Focus group, Germany","lastPublishedDoi":"10.21203/rs.3.rs-7187871/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7187871/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eHospitalizations resulting from ambulatory care sensitive conditions (ACSC) can be prevented or reduced through effective and timely ambulatory care. ACSC are used as an indicator of ambulatory care quality. As ACSC are influenced by contextual factors, such as disease prevalence and health system characteristics, they are usually assembled in national catalogues and updated within relevant time spans. In this study, we aim to update the 2015 catalogue of ACSC for Germany by Sundmacher et al. and validate our results in the context of previous research, taking into account relevant time trends and country-specific differences.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eWe use a structured methodology to derive the ACSC catalogue for Germany. First, we propose a list of potential diagnoses through (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) a literature review, (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) a data analysis on disease prevalence and regional variation for the German context and (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) a focus group meeting with patient representatives to incorporate patient opinion. Second, the proposed list is validated and expanded by a panel of medical experts in a structured consensus study.\u003c/p\u003e\u003ch2\u003eDiscussion\u003c/h2\u003e\u003cp\u003eThe ACSC catalogue for Germany will serve as a tool for informed decision making by providing the basis for assessing ambulatory care quality in the context of relevant time trends, identifying geographic areas with potential deficiencies in ambulatory care or comparing the overall state of ambulatory care in Germany with that in other countries. This information can be used to develop targeted improvement measures and, consequently, increase patient quality of life and reduce overall health care costs.\u003c/p\u003e\u003ch2\u003eTrial registration:\u003c/h2\u003e\u003cp\u003eThe German clinical trial register number is DRKS00035331. It can be accessed under \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.drks.de/DRKS00035331\u003c/span\u003e\u003cspan address=\"https://www.drks.de/DRKS00035331\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Date of trial registration is 7 February 2025.\u003c/p\u003e","manuscriptTitle":"Catalogue of ambulatory care sensitive conditions (ACSC) for Germany 2025: protocol of a group consensus study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-30 08:43:10","doi":"10.21203/rs.3.rs-7187871/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"48a3732d-d15c-4648-91bb-3f22d3d4766e","owner":[],"postedDate":"July 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-30T13:38:33+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-30 08:43:10","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7187871","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7187871","identity":"rs-7187871","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}