Prevalence and epidemiological characteristics of chronic pain in the Spanish population. Results from the pain barometer.

IF conceived the idea of the article. The fieldwork was performed by HdS, MD, SR, AE, and AS. MD and AS performed the statistical analysis. HdS and MD were mainly responsible for writing the manuscript. IF, AE, and SR were involved in revising the content. All the authors approved the final version of the manuscript.

This work was supported by a collaboration between the Foundation for the management of Biomedical Research of Cádiz (FCÁDIZ), and the Grünenthal Foundation. The Grünenthal Foundation is a private non‐profitable organization that promotes the dissemination of scientific knowledge and supports research.

The observational, cross‐sectional study, conducted within the framework of what we call the ‘Pain Barometer’, was carried out in the adult population in Spain (18–85 years). The sample population was obtained through volunteer sampling from a census that is the property of the company CINT (digital insights gathering platform focused on aims exclusively related to market research, providing access to panels of participants that meet the requirements of the European Society for Opinion and Marketing Research, ESOMAR and the International Organization for Standardization, ISO). A sample size of 7014 responses was required to ensure representativeness based on an estimated potential prevalence of 28.4% (result from a pilot study done to assess the sample size needed), with a 95% confidence level and accuracy of 13%. To guarantee representativeness by sex, age and Autonomous Community (specific territorial boundaries in Spain), stratified quotas were established proportional to the general population distribution. The information was collected between 13th and 20th of June 2022 using computer‐assisted web interviewing (CAWI) for individuals from 18 to 75 years of age, and computer‐assisted telephone interviewing (CATI) for individuals from 76 to 85 years of age. A total of 7058 interviews were obtained (6394 CAWI and 664 CATI). For the purposes of this study, two screening questions were used to identify the people with CP. Firstly, we asked: ‘ Have you suffered from pain at least 4 or 5 days a week during the last month? ’ If the answer was affirmative, the second question was: ‘ Is that pain chronic? That is, have you had it for at least 3 months? ’. A participant was considered to have ‘non‐chronic continuous pain’ if the first answer was affirmative and the second is negative. An individual was considered to have CP if the answers were affirmative to both questions. The following information was recorded: sociodemographic data (age, sex, educational level, and employment status); the presence of CP and the presence of non‐chronic continuous pain. Limitations to ADL (eating, sitting, getting up from a chair or bed, lying down, dressing and undressing, toileting, showering or bathing), the presence and level of anxiety and depression, quality of life and social support were also collected. Furthermore, records were taken about the following CP characteristics: cause or causes, duration, location, pain intensity, the latter using a 0–10 numerical rating scale, where 10 is the worst imaginable pain. Anxiety and depression were measured with the Hospital Anxiety and Depression Scale (HADS) (Zigmond & Snaith,  1983 ). This scale comprises 14 items grouped in two subscales (one for anxiety and one for depression), each with seven items. Each subscale is scored from 0 to 21, where higher scores denote higher levels of anxiety/depression. Scores over 10 indicate the presence of these pathologies, and scores between 8 and 10 are considered to be a possible indication of anxiety or depression (Herrero et al.,  2003 ). The 12‐item Short‐Form Health Survey version 2 (SF‐12v2) was used to assess health‐related quality of life. This tool includes 12 elements that make up its profile of eight dimensions: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, and mental health. It also includes two global ratings: the PCS‐12 for physical health and the MCS‐12 for mental health. The scores for these two summary dimensions are studentized with a median = 50 (Hayes et al.,  2017 ). Perceived social support was measured using the Duke‐UNC‐11 functional social support questionnaire (Bellón et al.,  1996 ). It consists of 11 items grouped into two subscales: confidential support (seven items) and affective support (four items). The former represents the ability to communicate with other people, and the latter evaluates the affection and empathy received, and whether they are disposed to welcoming or meeting other people such as friends or family. The scale's global score ranges from 11 to 55, where higher scores indicate higher perceived social support. Scores below 32 are considered a sign of low perceived social support. The prevalence of CP and non‐chronic continuous pain was calculated by point estimation and 95% confidence intervals (95% CI). The prevalence was subsequently calculated by sex, age group and region (Autonomous Community). The direct standardization method was used to compare the prevalence among the regions using the general Spanish population as the standard population. Crude and standardized rates are shown. A descriptive analysis was carried out, showing the absolute and relative frequencies (percentages) in the case of the qualitative variables, and the mean, median, standard deviation, and interquartile range for the quantitative variables. The Kolmogorov–Smirnov test confirmed the normality of the distribution of the variables. Bivariate analyses were performed to determine the differences in the characteristics of the subjects with CP, with non‐chronic continuous pain and without pain. The Chi‐square test, ANOVA test, or non‐parametric Kruskal–Wallis H test were used depending on the nature of the variables compared. A significance level α  = 0.05 was established. All the analyses were carried out with IBM SPSS V29, and the plots with Excel 365.

The final sample comprised 7058 subjects, a prevalence of CP being observed of 25.9% (95% CI;24.8–26.9), while that of non‐chronic continuous pain was 7.7% (95% CI; 7.1–8.3). The prevalence of CP was highest in the group between 57 and 75 years of age (30.4%, 95% CI = 28.2–32.6%). By contrast, the group of subjects aged between 18 and 37 presented the highest prevalence of non‐chronic continuous pain (10.8%, 95% CI = 9.4–12.2%). Regarding gender, the prevalence was higher among women in both the CP (30.5% vs. 21.3%) and non‐chronic continuous pain (8.8% vs. 6.6%) (Figure  1 ) groups. Prevalence of chronic and non‐chronic continuous pain by age group and sex. 95% CI (Chronic Pain): 18–37 = (17.1–220.7); 38–56 = (26.4–29.8); 57–75 = (28.2–32.6); 76–85 = (21.8–28.5). Men = (19.9–22.6); Women = (28.9–32). 95% CI (Non‐chronic Continuous Pain): 18–37 = (9.4–12.2); 38–56 = (5.9–7.8); 57–75 = (5.4–7.8); 76–85 = (3.2–6.7). Men = (5.8–7.4); Women = (7.8–9.7). The highest crude prevalence of CP was observed in Extremadura (31.5%), while Asturias presented the highest level for non‐chronic continuous pain (10.3%) (Figure  2 ). These differences were not significant when the adjusted prevalence were analysed (Figure  3 ). Crude prevalence of chronic pain and non‐chronic continuous pain by autonomous community. 95% CI Chronic Pain: Andalucía = (23.5–28.5); Aragón = (20.3–32.9); Asturias = (16.9–30.4); Islas Baleares = (21.9–35.9); Canarias22‐32.2); Cantabria = (13.4–31.3); Castilla y León = (18.6–27.5); Castilla‐La Mancha = (16.6–26.3); Cataluña = (24.8–30); Valencia = (22.9–29.3); Extremadura = (24–38.9); Galicia = (22.3–31); Madrid = (22.3–27.6); Murcia = (19.7–31.9); Rioja = (8.5–34); Navarra = (15.3–35.3); País Vasco = (20.5–30.3). 95% CI Non‐chronic continuous pain: Andalucía = (6.6–9.7); Aragón = (2.7–10); Asturias = (5.4–15.2); Islas Baleares = (1.2–8); Islas Canarias = (3.3–8.9); Cantabria = (0.9–11.9); Castilla y León = (5–10.9); Castilla‐ La Mancha = (5.1–11.7); Cataluña = (5.9–9); Valencia = (7.1–11.3); Extremadura = (0.5–6.9); Galicia = (6.1–11.8); Madrid = (5.5–8.7); Murcia = (3.4–10.7); Rioja = (2.4–20.4); Navarra = (1.1–13.4); País Vasco = (5.1–11.4). Adjusted prevalence of chronic pain and non‐chronic continuous pain by autonomous community. Among the 1825 subjects suffering from chronic pain, the mean duration was found to be 6.83 years (SD:8.41), with median = 4 (Q1 = 2, Q3 = 10) and a mean intensity of 6.78 (SD:1.72). A total of 57.6% of the subjects reported ‘severe’ pain, with a score between 7 and 9 on the NRS (Table  1 ). Characteristics of chronic pain ( N  = 1825). An injury consisting of a persistent, involuntary, and painful contraction of the muscle fibres that causes the affected muscle to be in constant tension. The causes of CP most frequently reported by the subjects were lumbar pain (58.1%), muscle contractures (50.6%), neck pain (46.2%), and arthrosis (33%). Of note was that 27.1% of the subjects did not know the cause of their pain. Regarding this question, the participant could select more than one cause. The subjects with CP also reported the site of their worst pain, the limbs and joints the parts of the body most frequently reported (33.1%), followed by back pain (28%) and generalized pain (13.2%) (Table  1 ). The comparative analysis of the three groups of subjects included in the study showed that those with CP had a higher mean age than those with non‐chronic continuous pain (51.5 years; SD = 15.6 vs. 45.3 years; SD = 18.6). Likewise, the frequency of both kinds of pain was found to be higher among the female subjects (58.7% and 56.9%). Regarding educational level and employment status, fewer individuals with a university education or who were currently working were found in the CP group compared with the other two groups (Table  2 ). In contrast, a higher percentage (46.5%) of subjects with CP who were currently working and had taken sick leave in the last year was found compared with the non‐chronic continuous pain group (38.8%) and pain‐free group (23.3%) (Table  2 ). Comparison of sociodemographic variables and physical and mental health status in populations with chronic pain, non‐chronic continuous pain and without pain. Pearson's Chi square test. Kruskal–Wallis H. Regarding the limitations to activities of daily living reported by the subjects, what stands out is that the individuals with pain (both chronic and continuous pain) experienced greater difficulty in carrying out these activities than the subjects without pain. Those with CP reported more problems, especially with regard to activities such as standing up or sitting down on a chair or bed (Table  2 ). The analysis of the mental health of the three groups revealed that the subjects in the pain‐free group presented better results than those in the two groups with pain, on both the HADS anxiety and depression scales. However, once again, the subjects with CP presented the worst results (Table  2 ). Likewise, the percentage of subjects suffering depression (HAD‐D>10) and anxiety (HAD‐A>10) was higher in the CP group, 22.2% of them affected by depression compared with 14.2% of those in the non‐chronic continuous pain group and 6.9% of those not experiencing pain. Similar results were found for the presence of anxiety, which was also more frequent in the subjects with CP (27.6%) than in the other groups (Table  2 ). The group of subjects without pain scored a mean of 41.6 points (SD = 10.2) in perceived social support. This value was higher than the ones observed among both the subjects with CP (37.1 points; SD = 11.6) and those with non‐chronic continuous pain (39.18; SD = 10.54). Moreover, 29% of the subjects with CP considered that they received little support, whereas those with non‐chronic continuous pain or without pain reported this less frequently (22.3% and 15.5%, respectively) (Table  2 ). Lastly, it is worth highlighting that the subjects without pain presented higher scores in both the physical and mental components of the SF‐12v2 quality‐of‐life scale than the patients with non‐chronic continuous pain or CP. Likewise, the subjects with CP scored lower than those reporting non‐chronic continuous pain on both the physical component (38 points; SD = 10 vs. 45; SD = 8.7) and the mental component (42.4 points; SD = 11.6 vs. 44.6; SD = 10.9) (Table  2 ).

This study presents the prevalence of CP and non‐chronic continuous pain and its consequences in a wide and representative sample of the Spanish population, and the results are compared with a group of subjects without pain. One of the results that stand out is that the prevalence of chronic pain in the population analysed was 25.9%. This prevalence is higher than those observed in earlier studies conducted in Spain (Dueñas et al.,  2015 ; Langley et al.,  2011 ), and in other countries such as India (13%) (Dureja et al.,  2014 ), the Philippines (13.6%) (Lu & Javier,  2011 ), Morocco (21%) (Harifi et al.,  2013 ), or Canada, where prevalence ranged between 15% and 19% (Reitsma et al.,  2011 ). It is, however, closer to the data observed recently in the USA (Yong et al.,  2022 ). Furthermore, the prevalence of non‐chronic continuous pain was 7.7%, a result that, to our knowledge, has not been reported in other studies and that could serve as a warning of the potential for these subjects' pain to become a chronic condition. It is important to highlight the variability of the results described in the literature. This variability was reported by different authors (Dueñas, Ojeda, Salazar, Mico, & Failde,  2016 ; Mills et al.,  2019 ), and also brought to light by Steingrímsdóttir et al. (Steingrímsdóttir et al.,  2017 ) in a systematic review including 86 articles published between 1989 and 2015. This review (Steingrímsdóttir et al.,  2017 ) present the results for prevalence ranging between the 8.7% found in a study conducted in Singapore (Yeo & Tay,  2009 ) and the 64.4% observed in another from the USA (Watkins et al.,  2008 ). The authors attribute the differences to factors such as the diversity of the population included in each study or the method used to obtain the results, which in some cases may be overestimated (Steingrímsdóttir et al.,  2017 ). Authors such as Mills et al. (Mills et al.,  2019 ), in line with Steingrímsdóttir et al., highlight the importance of correctly defining the case definition, ascertainment methods, time, place and the population studied in CP studies in order for results to be comparable. Additionally, all these differences could be attributed to the problem of inconsistency in the definition of chronic pain, for which, despite several decades of debate, there appears to be convergence in the literature, namely that 3 months is the cut‐off duration between acute or sub‐acute versus chronic pain. Despite the differences described, it would seem reasonable to think that the increase in CP observed in Spain could be related to the long life expectancy in the Spanish population, which is estimated at 86 years for women and 80 years for men, ages in which pain conditions could be more common (Ministerio de Sanidad,  2023 ). However, rather unexpectedly, the highest prevalence in our study was observed in the group aged between 57 and 75 (30.4%). Another possible explanation is the so‐called ‘survival effect’ described by other authors, whereby subjects that reach old age and survive fatal disease generally consider the presence of pain to be a natural part of growing old that does not overly concern them as it is not a cause of death (Humbria et al.,  2022 ; Skovron,  1992 ). As expected, and in line with other studies, the prevalence of CP was higher in women. Studies conducted in the general population and in subjects treated in health centres have highlighted the greater frequency, higher intensity, and longer duration of CP in the female population, in addition to the higher percentage of generalized pain (Dueñas et al.,  2015 ; Mills et al.,  2019 ; Steingrímsdóttir et al.,  2017 ). Along the same lines, some studies have noted that men are less likely to express pain, and that they do so differently to women (Jaworska & Ryan,  2018 ), who often report more pain sites than men and have lower pain thresholds and tolerance (Gobina et al.,  2019 ). Moreover, evidence suggests that women are different in terms of their sensitivity to analgesia, and that they are more likely to seek alternatives to treat their pain than men (Osborne & Davis,  2022 ). These differences have been attributed to both biological and social, cultural and gender role factors. Biological factors undoubtedly play an important role in the differences observed in the brain between men and women with CP. However, there are also factors related with gender such as socialization, cognition and life experiences that contribute to the differences observed in the brain (Osborne & Davis,  2022 ). In view of these results, it is clear that it is necessary to take these factors into account when analysing pain in men and women. Understanding how they interact and influence the pain process may make it easier to pinpoint the treatment and most suitable strategies for addressing each individual's pain. The most frequent site of chronic pain in the subjects of this study was lumbar pain, which affected 58.1% of them. However, it is important to highlight that 27.1% of the respondents did not know the cause of the pain, even though it was severe and long‐lasting. This result might relate to the fact that the pain process of some of the respondents was still under study. This is a plausible hypothesis if we bear in mind that the mean time reported by the respondents to be attended to in a pain unit was 10.5 months (data not shown). The CP intensity reported by over half of the respondents was high, although similar to the levels found in a study conducted by our group a few years ago following the same methodology (Dueñas et al.,  2015 ). It is, however, higher than that reported by other authors. In this sense, Fayaz et al. (Fayaz et al.,  2016 ), in a systematic review of CP, found that between 10.4% and 14.3% of the subjects included in the studies reported moderate‐to‐severe chronic pain. These differences can be attributed to the use of different scales for measuring the intensity of the pain. In this systematic review, the authors selected the papers using the ‘Chronic Pain Grade Scale’, developed by Von Korff et al. ( 1992 ), in which several items are used to evaluate pain intensity, including the degree of pain at the moment, and in the last 6 months, which can result in a different average pain intensity Another potential cause of the results being different to those reported in other countries could be related to the contextual cultural, economic, and political variables, as reported by Zimmer et al. ( 2022 ). However, we have not been able to assess these variables since this information was not included in the questionnaire. In the comparative analysis of the three groups in the study (chronic pain, non‐chronic continuous pain and without pain), the health of those reporting CP was observed to be more affected, essentially with regard to the consequences for performing ADL and the presence of anxiety and depression. Previous studies have highlighted that chronic pain influences patients' lives, causing functional changes (such as in sleep, energy, and work), social changes, essentially lack of productivity and disability, and emotional disorders (Pereira et al.,  2021 ). These changes cause untold suffering (Clara Vélez et al.,  2013 ) and significantly reduce patients' quality of life (Soriano‐Maldonado et al.,  2015 ). In line with these studies, the results for quality of life in the two groups with pain were worse, with the impact on the mental and physical sphere even greater in the CP group. These results could be explained by the prolonged presence of the pain and associated impairment of daily life having a psychological effect on the subjects, who feel impotence and despair at being unable to control it, which, in turn, worsens the pain and the response to treatment (Senba,  2015 ), leading to a decrease in quality of life (Hong et al.,  2014 ; Kioskli et al.,  2019 ; Morete et al.,  2018 ). Social and family support are key elements in patients with pain as it improves overall quality of life and reduces physical disability and the symptoms of distress (Helmhout et al.,  2010 ; Jensen et al.,  2011 ; Ojeda et al.,  2014 ). This was shown among the subjects in the study, and especially in the CP group, who reported less social support than the participants in the non‐chronic continuous pain and pain‐free groups. Finally, we must consider some strengths and limitations of the present study. First of all, although this study was carried out on a large representative Spanish sample using a rigorous selection procedure, the sample was selected from volunteers, leading to a potentially biased sample. Volunteer participants are likely to be more motivated to participate due to the presence of pain, leading to a possible overestimation of the prevalence of chronic pain. On the other hand, people over 85 years were excluded from the sample due to access and participation difficulties. This population is usually at greater risk of suffering from chronic pain, so we might be underestimating the global prevalence. In any case, it is necessary to point out that while the results are very accurate, they may not faithfully represent the general population. On the other hand, obtaining information from the online survey could be an acceptable way of accessing the selected population, this being a common procedure in other studies (Langley et al.,  2011 ; Loban et al.,  2017 ; Torrejón‐Guirado et al.,  2024 ). As such, we consider that the information provided is likely to be valuable in the case of both the subjects with CP and with non‐chronic continuous pain. Likewise, comparing the sociodemographic aspects and the health status of the three groups of subjects (without pain, with non‐chronic continuous pain and with chronic pain) has enabled us to identify aspects that especially affect people with CP, unlike other studies that did not perform this comparison. By contrast, a potential limitation of the study was that the information collected was self‐reported. However, validated scales were used to measure many of the aspects analysed, thereby making the information obtained more valid and reliable. Finally, it is worth mentioning that the definitions of ‘non‐chronic continuous pain’ and ‘chronic pain’ used in the study are in agreement with previous studies carried out in Spain, with the aim of updating the existing information. It was considered that using the same definition was necessary to be able to compare the results. The definition may differ, however, from those used in other studies. This might partly explain the differences in prevalence found in this and other studies.

We hereby declare that this paper is our own work, except where acknowledged, and has not been submitted elsewhere.

Chronic pain affects one in four Spanish people and is detrimental to ADL, the mental and physical health and quality of life of those who suffer from it. Differences by sex and age exist in its frequency and there is a high percentage of subjects with CP of an unidentified cause to whom it is necessary to pay special attention. Identifying subjects with non‐chronic continuous pain is fundamental in order to prevent their pain from becoming chronic.

Pain is defined as an unpleasant sensory and emotional experience that is influenced by biological, psychological, and social factors, and it cannot be explained solely by sensory activity (Asociación Internancioal para el Estudio del Dolor,  2020 ; Dolor.com,  2020 ). Although pain can be acute or chronic, continuous or intermittent, chronic pain (CP) is experienced for a prolonged period of time and is a highly disabling disease that affects both the patient themselves (Cohen et al.,  2021 ; Dueñas et al.,  2015 ) and their relatives (Ojeda et al.,  2014 ; Rønne et al.,  2023 ), having a major impact on their daily lives. The difficulty in performing work‐related activities, doing physical activity or completing basic activities of daily living (ADL) entails a great personal burden (de Sola et al.,  2016 ; Denham‐Jones et al.,  2022 ; Ojeda et al.,  2014 ) and affects psychological and social domains, which, in turn, leads to the significant use of healthcare resources and an impaired quality of life (Dueñas, Ojeda, Salazar, Fernández‐Palacín, et al.,  2016 ; Dueñas, Ojeda, Salazar, Mico, & Failde,  2016 ; Meints & And,  2018 ). Studies published several years ago estimated a worldwide prevalence of CP of 20%, meaning that around 1.6 billion people suffer from this condition (Plataforma de Organizaciones de pacientes y Sociedad Española del Dolor,  2018 ). These results are in line with those observed in the USA in 2022 (Yong et al.,  2022 ) and also with those described in a systematic review in the UK, although, in this last case, great variability existed in the data reported, as the prevalence ranged between 13% and 50% depending on the study (Breivik et al.,  2006 ; Fayaz et al.,  2016 ). Studies conducted in other countries have also presented mixed results, with prevalence differing according to the population analysed and the definition of CP used (Mills et al.,  2019 ; Steingrímsdóttir et al.,  2017 ). In Spain, studies performed between 2011 and 2015 estimated that the prevalence of CP in the general population was between 17% and 18%, with a higher prevalence found among women and the more elderly segment of the population (Dueñas et al.,  2015 ; Langley et al.,  2011 ; Plataforma de Organizaciones de pacientes y Sociedad Española del Dolor,  2018 ). Moreover, according to data from the 2020 European Health Survey, the prevalence of pain suffered in the last 4 weeks was 44% in Spain. These data, however, are not comparable because the criterion used to define pain are different and does not meet the generally accepted definition of CP. In view of the variability of the results observed between countries, and taking into account the lack of up‐to‐date information, we decided to conduct a study with the aim of updating the prevalence of CP in Spain, using the criteria followed by Dueñas et al. in 2015 (Dueñas et al.,  2015 ). A further objective was to analyse its impact on ADL, mental health and quality of life. The secondary aims were to analyse the clinical and epidemiological differences between three groups: subjects with CP, subjects with non‐chronic continuous pain, and subjects with no pain. These differences were not analysed in earlier studies.

None.