Risk factors for surgical site infections after hysterectomy: A systematic review and meta-analysis.

Endometrial cancer (EC) and Cervical cancer (CC) are significant global health concerns and are among the most common gynecological malignancies leading to mortality among women. 1 Just in 2020, 417,367 new cases of EC were reported worldwide, with more than 97,370 deaths attributed to the disease, accounting for nearly 4% of all cancer-related deaths in women annually. 2 Hysterectomy plays an essential role, including both benign conditions—such as uterine fibroids, abnormal uterine bleeding, and endometriosis—as well as malignant conditions like EC and CC, offering both curative and palliative outcomes. 3 However, this approach is associated with a risk of postoperative complications, such as surgical site infections (SSIs) that contribute to substantial morbidity, impact patient recovery, and overall treatment efficacy, 4 , 5 affect quality of life, and place a financial strain on healthcare systems. 6 , 7 Therefore, understanding and mitigating the risk factors for SSIs in patients undergoing hysterectomy is essential to improving surgical outcomes and reducing healthcare costs. Numerous studies have explored the potential risk factors associated with SSIs after hysterectomy. 8 Commonly identified predictors include high body mass index, diabetes mellitus, surgical procedure and operative time, and the American Society of Anesthesiologists (ASA) score. These factors, often interrelated, highlight the complex interplay of patient characteristics, surgical techniques, and perioperative management in determining the risk of infection. Despite these insights, there is still a significant variability in the findings across different studies. Inconsistencies in study designs, populations, and definitions of SSIs have contributed to a lack of consensus regarding the relative importance of specific risk factors. As SSIs are associated with a substantial healthcare burden, a comprehensive evaluation of the risk factors associated with this complication in the context of a hysterectomy is necessary. Identifying modifiable and non-modifiable factors could guide clinicians in implementing targeted preventive strategies, optimizing perioperative care, and ultimately improving patient outcomes. This meta-analysis aims to assess the link between key risk factors and the occurrence of SSIs after hysterectomy.

This systematic review and meta-analysis were done based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 9 and pre-registered with the International Prospective Register of Systematic Reviews (PROSPERO: # CRD42025629931). The research question was formulated using the PICO framework to address the factors contributing to SSIs after a hysterectomy. Specifically: Women undergoing hysterectomy. Intervention/Exposure: Potential risk factors such as obesity, diabetes, surgical approach, operative time, and ASA score. Patients without these risk factors or with lower levels of exposure. Incidence of SSIs. The primary research question was: What are the risk factors associated with SSIs after hysterectomy? A comprehensive search of PubMed, Embase, Cochrane Library (CENTRAL), and Scopus databases was done using MeSH key words. The key words used for developing the search strategy include Hysterectomy”; “Uterus Removal”; “Uterine Surgery”; “Surgical Wound Infection”; “Surgical Site Infection”; “Postoperative Infection”; “Wound Infection”; “SSI”; “Risk Factors”; “Risk Factor”; “Associated Factors”; “Predictors”; “Determinants”. No restrictions were placed on the year of publication and language, to capture all potentially relevant data, but only studies published in English were considered. In addition to database searches, grey literature, conference abstracts, and the bibliography of included studies were searched to ensure comprehensiveness. The grey literature search was carried out using www.opengrey.com . The last electronic search was carried out on 30 th January 2025. The search strategy for all databases is provided in Table-I . Search strategy for digital databases. In the first stage of study selection, two reviewers (Y.Y, T.Z) independently screened titles and abstracts to assess relevance. Second, full texts of potentially suitable studies were evaluated using predefined eligibility criteria. Disagreements were resolved by discussion. Studies reporting SSIs as an outcome after hysterectomy. Observational studies (cohort, case-control) and randomized controlled trials (RCTs). Studies reporting specific risk factors and their association with SSIs. Full-text articles available in English. Studies reporting SSIs as an outcome after hysterectomy. Observational studies (cohort, case-control) and randomized controlled trials (RCTs). Studies reporting specific risk factors and their association with SSIs. Full-text articles available in English. Studies without explicit reporting of SSIs. Case reports, reviews, or editorials. Studies without extractable data or overlapping datasets. Studies without explicit reporting of SSIs. Case reports, reviews, or editorials. Studies without extractable data or overlapping datasets. Two reviewers (Y.Y, T.Z) independently used a standardized form in an Excel spreadsheet to retrieve study characteristics (e.g., author, year, design, sample size), definitions and incidence of SSIs, examined risk factors, and reported effect sizes and measures. Discrepancies were resolved by consensus, and missing data were sought by contacting study authors when feasible. Randomized Controlled Trials (RCTs) were assessed using the Cochrane Risk of Bias 2 (RoB 2) tool ( https://methods.cochrane.org/bias/resources/rob-2-revised-cochrane-risk-bias-tool-randomized-trials ), evaluating five domains: randomization process, intervention deviations, missing outcome data, measurement of outcomes, and selection of reported results. For observational studies, the Newcastle-Ottawa Scale (NOS) was applied to evaluate the selection of study groups, the comparability of groups, and the measurement of exposure or outcome ( https://ohri.ca/en/who-we-are/core-facilities-and-platforms/ottawa-methods-centre/newcastle-ottawa-scale ). Each study was assigned a quality score, and sensitivity analyses were done to examine the impact of including lower-quality studies. The extracted data were subjected to qualitative and quantitative analysis. A random-effects meta-analysis was conducted using RevMan 5.4.1v (Cochrane Collaboration, UK) to account for heterogeneity among studies. Effect sizes for identified risk factors were pooled as odds ratios (ORs) with 95% confidence intervals (CI). Heterogeneity was assessed using the I² statistic, with thresholds for low (70%) heterogeneity. Potential publication bias was evaluated using funnel plots for asymmetry. P<0.05 was considered significant.

As detailed in the PRISMA flow chart ( Fig.1 ), 712 records were identified from four databases (PubMed: 155, EMBASE: 176, Scopus: 232, CENTRAL: 149). After removing 35 duplicates, 677 records were screened based on titles and abstracts, excluding 659 irrelevant studies. Eighteen full-text reports were retrieved and assessed for eligibility, with two excluded (one conference abstract and one lacking relevant outcomes). Ultimately, 16 studies 10 - 25 were included in the systematic review and meta-analysis. Study Selection Flow Chart The included studies were conducted across eight countries, with majority of studies originating from the United States, 12 , 15 , 18 – 20 , 23 , 24 followed by China, 10 , 11 , 17 , 18 Japan 16 , 25 and one study each from Iran, 13 Mexico, 14 Turkey, 22 and Finland. 21 Regarding study design, most (n=12) studies 15 - 18 , 20 - 22 , 24 - 27 - 30 were retrospective cohort, followed by two cross-sectional studies, 14 , 23 one prospective cohort studies, 18 and one randomized controlled trial. 13 The total sample size across all studies was 165,589 participants, with individual study sizes ranging from 47 14 to 66,001. 12 The mean sample size was approximately 10,349 participants. The age of participants varied widely, with the mean or median age ranging from 46 years 16 to 67.5 years. 21 The overall mean age, where reported, was 55.1 years, representing a middle-aged to older population typically undergoing hysterectomy. The studies reported a variety of surgical approaches. Abdominal hysterectomy was the most frequently performed procedure, 12 , 15 , 19 followed by laparoscopic hysterectomy 10 , 16 and vaginal hysterectomy. 18 , 23 Several studies compared multiple surgical methods, such as the study by Guo et al. 2020, 18 which assessed open, vaginal, laparoscopic, and robotic hysterectomies. Indications for surgery varied, focusing on malignant conditions, 17 , 24 benign conditions, 18 , 19 and studies encompassing both. 11 The prevalence of SSIs varied significantly, ranging from 0.4% in the post-bundle group 18 to 14.47%. 17 The mean SSI prevalence across studies was approximately 6.8%. Factors influencing these rates likely include variations in patient populations, surgical techniques, and infection prevention protocols. Consistently reported risk factors included obesity or BMI >30 kg/m 2 , diabetes mellitus and prolonged operative time. Other factors, such as ASA score, smoking, postoperative serum albumin levels, and surgical approach, were also significant. Unique variables, like postoperative antibiotic duration 11 and the use of Seprafilm, 21 were highlighted in specific studies. Follow-up durations were inconsistently reported. In studies that provided this information, follow-up durations averaged approximately 1.5 months. One study 17 reported a shorter follow-up of 30 days. Table-II summarizes the characteristics of the included studies. General Characteristics of included studies. BMI- Body Mass Index; ASA- American Society of Anaesthesiologists; CRP – C-Reactive Protein; NR- Not reported; Hb- Hemoglobin; USA- United States of America; LASCH- Laparoscopic supracervical hysterectomy; TLH - Total laparoscopic hysterectomy; LAVH - Laparoscopic-assisted vaginal hysterectomy; TVH - Total vaginal hysterectomy; ASCH - Abdominal supracervical hysterectomy; FIGO - International Federation of Gynecology and Obstetrics; The meta-analysis assessed various risk factors for SSIs after hysterectomy, integrating data from multiple studies to provide pooled impact estimates. Obesity (BMI >30 kg/m²) significantly increased the risk of SSIs, with a pooled OR of 3.34 (95% CI: 2.45–4.56), highlighting the role of impaired wound healing and reduced vascularity in obese patients ( Fig.2 ). Forest plot: Effect of BMI >30kg/m2 on surgical site infection risk after hysterectomy. Age as a risk factor, with older patients exhibiting similar susceptibility to SSIs (OR = 1.00, 95% CI: 0.91–1.09), p=0.98, showed no statistical significance ( Fig.3 ). Similarly, diabetes mellitus emerged as a strong predictor of SSIs, with an OR of 1.82 (95% CI: 1.41–2.35), with a p-value of <0.00001. Smoking, a modifiable risk factor, was associated with a 1.76-fold increased risk of SSIs (OR = 1.76, 95% CI: 1.37–2.26) with a p-value of 2 hours) was linked to a nearly 1.5 -fold increased likelihood of SSIs (OR = 1.59, 95% CI: 1.19–2.11), p=0.002, underscoring the importance of efficient surgical workflows to minimize tissue exposure and microbial contamination. Forest plot: Effect of Age on surgical site infection risk after hysterectomy. Patients with (ASA) scores >3, reflecting higher baseline comorbidities, were at a significantly increased risk of SSIs (OR = 1.81, 95% CI: 1.51– 2.17) with a p-value of <0.00001. Similarly, blood transfusions were associated with an OR of 1.13 (95% CI: 0.91–1.41), p=0.27, indicating no potential link between transfusion-related immunomodulation and infection susceptibility. Additional risk factors included prolonged hospital stays (>1 day) (OR = 2.47, 95% CI: 1.78–3.43, I² = 68%), duration of drainage >7 days (OR = 1.85, 95% CI: 0.95–3.60, I² = 60%), and infected wounds (OR = 2.62, 95% CI: 1.87–3.66, I² = 89%). Patients undergoing open approach hysterectomy had nearly a threefold increased risk of SSIs (OR = 2.88, 95% CI: 2.24–3.72, I² = 35%) compared to minimally invasive approaches. Similarly, bowel resection, often performed in complex oncologic surgeries, was associated with the highest risk among all factors (OR = 3.07, 95% CI: 1.71–5.49, I² = 57%). Only one randomized clinical trial 18 with low risk of bias was included in this review. And rest of the observational studies were of good quality with NOS score ranging between 6-8. ( Table-III ) No publication bias was detected and confirmed using visual inspection of plots. Quality Assessment of Observational studies using Newcastle-Ottawa Scale.

This systematic review and meta-analysis identified key risk factors for SSIs following hysterectomy, including obesity (BMI > 30 kg/m²), diabetes, smoking, prolonged operative time (>2 hours), and higher ASA scores (ASA score > 3). The findings also highlighted procedure-related factors such as open surgical approaches, blood transfusions, prolonged hospital stays, and bowel resection, which were strongly associated with increased SSI risk. These findings have direct clinical implications, suggesting that existing SSI risk scores should be updated to reflect high-impact factors such as obesity, diabetes, prolonged operative time, and ASA scores. Incorporating these into preoperative risk calculators could improve SSI prediction and guide targeted interventions. Clinicians should prioritize modifiable risk factors through optimized patient preparation and consider minimally invasive approaches where feasible to reduce infection risk following hysterectomy. By implementing tailored prevention protocols and further exploring advanced surgical technologies, the burden of SSIs post-hysterectomy can be significantly reduced, leading to improved patient outcomes and substantial reductions in healthcare costs. Future research should focus on standardizing SSI definitions and follow-up durations to facilitate comparability across studies. Prospective studies with more extensive, multicenter cohorts are needed to validate the findings and assess the effectiveness of targeted interventions. Additionally, exploring the impact of advanced surgical technologies, such as robotic-assisted hysterectomy, on SSI rates could provide valuable insights. Finally, implementing evidence-based infection prevention measures in clinical practice and evaluating their outcomes should be prioritized. YY and TZ: Study design, literature search and manuscript writing. YY and TZ: data collection, data analysis and interpretation. Critical review. TZ: manuscript revision and validation and is responsible for the integrity of the study. All authors have read and approved the final manuscript.

This systematic review and meta-analysis aimed to evaluate the risk factors associated with SSI following hysterectomy. The included studies spanned diverse geographic regions and varied in design, providing a comprehensive understanding of factors contributing to SSIs post-hysterectomy. An overall mean SSI prevalence in the entire cohort was 6.8%, with rates ranging from 0.4% to 14.47%. Common risk factors for SSIs included obesity, diabetes mellitus, prolonged operative time, smoking, and higher ASA scores > 3. These findings emphasize the multifactorial nature of SSIs, with both patient-related and procedural factors playing significant roles. The results also underscore the importance of infection prevention strategies tailored to high-risk patients. Hysterectomy remains one of the most commonly performed gynecological surgeries worldwide. 26 , 27 Indications for the procedure include both benign conditions, such as uterine fibroids and abnormal uterine bleeding, and malignant conditions, such as endometrial and cervical cancers. 28 Several included studies focused on cervical cancer, highlighting its surgical complexity and associated risks. 10 , 12 , 15 , 16 , 18 , 20 Cervical cancer, a leading cause of cancer-related mortality among women, often requires radical hysterectomy, which is associated with higher morbidity, including an increased risk of SSIs. 29 SSIs following hysterectomy significantly impact patient recovery, increasing hospital stays, readmission rates, and healthcare costs. Secondary infections often result from wound contamination during surgery, impaired immune responses, or prolonged operative time. 30 – 32 This study showed that the incidence of SSIs varied depending on the surgical approach (abdominal, laparoscopic, or vaginal) and the comorbidities, which is consistent with previous research. Abdominal hysterectomy, for instance, is often associated with higher SSI rates compared to laparoscopic or robotic approaches due to the larger incision size and greater exposure of surgical sites. 33 The analysis revealed that obesity increases the risk of SSIs by more than two-fold. This association aligns with previous studies 8 , 34 highlighting how increased adiposity impairs vascularity, delays wound healing, and creates an environment conducive to bacterial growth. 35 Similarly, diabetes mellitus significantly elevates the risk of infections due to hyperglycemia-induced immune suppression and delayed tissue repair. 36 These findings underscore the importance of preoperative optimization for obese and diabetic patients to reduce SSI risk. This study showed that older patients did not show any significant risk to SSIs. Advanced age is often associated with declining immune function and a slower healing process, particularly in patients undergoing complex procedures such as hysterectomy for malignancies. 37 The impact of smoking was equally pronounced, increasing the odds of infection by 1.83 times. Smoking impairs tissue oxygenation and vascularity, exacerbating surgical site complications, 38 making smoking cessation an essential component of preoperative care. The study demonstrated a significant association of procedure-related factors with the incidence of SSIs. Extensive operative time (>2 hours) was associated with nearly a threefold increased risk of SSIs, likely due to a prolonged tissue exposure and microbial contamination. 30 Compared to minimally invasive methods, open surgical approaches was linked to a significantly higher SSIs risk, reinforcing the advantages of laparoscopic and robotic techniques in reducing infection rates. Similarly, blood transfusions and ASA scores >3 highlighted the interplay between procedural complexity, patient comorbidities, and immune responses in increasing infection susceptibility. 39 Specific conditions, such as prolonged hospital stays (>1 day), duration of drainage >7 days, and infection, further compounded the risk of SSIs. The association of bowel resection with the three-fold odds ratio among all factors highlights the complexity and infection-prone nature of extensive surgical interventions, often performed in cases of advanced cervical cancers. In the context of cervical cancer, these risk factors become particularly relevant, as surgeries for malignant conditions, such as radical hysterectomy, are inherently more complex, often require extensive tissue dissection, lymphadenectomy, or concurrent procedures, involve longer operative times and larger surgical fields further increasing the risk of SSIs compared to procedures for benign indications. 40 , 41 Moreover, patients with cervical cancer may present with immunosuppression due to advanced disease stages or prior chemoradiotherapy, compounding the susceptibility to infections. For instance, patients with advanced disease, such as those in FIGO stage IV were found to be at a higher risk of SSIs due to prolonged operative times, impaired wound healing, and systemic immune dysfunction. 17 Anastomotic leaks, also particularly in the context of gynecologic oncology procedures involving bowel resection, have been strongly associated with adverse postoperative outcomes, including a significantly increased risk of surgical site infections. 42 Despite these findings, the review identified considerable heterogeneity among the included studies. It is possible that this variability stems from the variations in patient populations, surgical techniques, SSI definitions, and follow-up durations. While some studies exclusively focused on malignant indications, such as endometrial or cervical cancer, others included mixed populations with benign conditions, introducing variability in infection rates. Differences in healthcare resources, surgical protocols, and antibiotic prophylaxis further contributed to the observed variability, affecting the generalizability of findings. For example, studies from high-resource settings like the USA often incorporated advanced infection prevention methods 18 that lowered SSI rates, whereas resource-limited settings may face challenges in implementing such protocols. This review has several strengths and limitations. The strengths include the systematic synthesis of data from various studies conducted across multiple countries, ensuring a comprehensive and diverse analysis. The inclusion of various study designs and surgical approaches enhanced the generalizability of the findings, while the use of rigorous inclusion and exclusion criteria minimized bias, improving reliability. However, significant heterogeneity among studies limited the ability to pool data in certain analyses. Variations in SSI definitions and follow-up durations may have resulted in underreporting or inconsistencies, and some studies lacked detailed reporting of confounding variables, which could influence the observed associations between risk factors and SSIs. A notable limitation of this review is the geographic concentration of included studies, with nearly half originating from the United States. A major limitation is the pooling of benign, oncologic, and mixed hysterectomy cases without subgroup analysis. These populations differ markedly in surgical complexity and baseline risk, particularly with oncologic procedures having higher complication rates. This heterogeneity may introduce confounding and limits the validity and clinical interpretability of the pooled results. This may introduce bias related to healthcare system differences, surgical protocols, and resource availability, potentially limiting the generalizability of findings to low- and middle-income settings. Only a minority of the included studies explicitly reported infection prevention bundles or detailed antibiotic protocols. Where described, these strategies included perioperative SSI prevention bundles 18 , closure-focused protocols such as dedicated closing tray or abdominal closure protocols 15 , optimization of prophylactic antibiotic selection in line with guidelines 20 , adjunctive topical antimicrobial use such as preoperative vaginal metronidazole gel in addition to standard systemic prophylaxis 13 , and postoperative antibiotic duration or perioperative antisepsis practices. 11 , 14 Collectively, these reports highlight substantial variability and frequent underreporting of infection prevention practices across studies. Additionally, follow-up duration was inconsistently reported, with most studies lacking clear timelines for postoperative assessment. This variability may affect the detection and reporting of SSIs, introducing potential detection bias that could influence the observed associations. The inconsistency in threshold definitions for key risk factors across studies could possibly contribute to the heterogeneity. For instance, BMI cutoffs and operative time thresholds varied notably, with some studies of united studies using a BMI >30 kg/m² considered for obesity and Asian studies considering BMI >25 kg/m 2 for the same. Despite these limitations, the review provides valuable insights into modifiable and non-modifiable risk factors for SSIs, emphasizing the importance of targeted interventions to improve patient outcomes.