Impact of climatic variables on postoperative outcomes in various surgical disciplines: a systematic review.
Clinical Snapshot
PICO Framework
| P — Population | Adult surgical patients across various surgical disciplines undergoing operative procedures in clinical settings |
| I — Intervention | Exposure to climatic variables including elevated ambient temperature, humidity, precipitation, and seasonal variation |
| C — Comparator | Lower or baseline climatic exposures (lower temperature, lower humidity, reference seasons) |
| O — Outcomes | Postoperative complications, primarily surgical site infections (SSIs), pneumonia, and other procedure-specific complications |
Bottom Line
This systematic review from the Medical University of Graz examines the relationship between climatic variables — principally temperature, humidity, and seasonality — and postoperative complications across surgical disciplines. Fifteen studies were included, and narrative synthesis suggests that elevated ambient temperature and humidity are associated with increased surgical site infection rates, with some individual studies reporting significant effects from even a one-degree Celsius temperature rise. Seasonal patterns in infection and pneumonia rates were also observed, though these varied by geography and procedure type. However, the review has important methodological limitations: no meta-analysis was performed, no GRADE assessment was conducted, grey literature was not searched, and no PROSPERO registration is reported. The included evidence base is small and heterogeneous, with inadequate confounder adjustment across primary studies. The findings are hypothesis-generating and should not drive immediate practice change. For Australian clinicians, the results highlight a plausible and clinically intuitive association warranting prospective investigation, particularly in high-temperature, high-humidity settings. Enhanced perioperative infection surveillance during peak climatic risk periods represents a pragmatic, low-harm response pending higher-quality evidence.
Key Findings
P Value: Not reported at the review level
Effect Size: No pooled effect size reported. Narrative synthesis indicates that high ambient temperatures were frequently associated with increased SSI risk; some large individual studies reported that a one-degree Celsius rise in temperature significantly elevated infection rates
Primary Outcome: Surgical site infections (SSIs) as the primary postoperative complication examined in relation to climatic variables
Nnt Or Sensitivity: Not calculable from available data; no NNT, odds ratio, relative risk, or hazard ratio reported at the systematic review level. Individual study-level effect estimates were not synthesised
Confidence Interval: Not reported at the review level; no meta-analytic pooling performed
Clinical Application
Immediate practice change is not warranted based on current evidence. However, findings support consideration of climate-adaptive infection control protocols, enhanced SSI surveillance during high-temperature and high-humidity periods, and optimisation of operating theatre environmental controls. Scheduling of high-risk elective procedures during lower-risk climatic periods may be a low-cost, low-harm intervention worth piloting. Australia's diverse climate zones — from tropical northern regions (Darwin, Cairns) to temperate southern cities (Melbourne, Hobart) — make this question particularly relevant. The RACGP and ANZCA do not currently provide climate-specific perioperative guidelines. SSI prevention is addressed in the Australian Commission on Safety and Quality in Health Care (ACSQHC) guidelines, but climatic variables are not incorporated. In tropical and subtropical Australian settings (Queensland, Northern Territory), where ambient temperatures and humidity are consistently elevated, these findings may have greater immediate relevance. TGA-approved antimicrobial prophylaxis protocols and PBS-listed agents are not currently stratified by climatic risk. This review provides a rationale for Australian surgical quality registries (e.g., ANZHSN, ACHS) to begin capturing seasonal and climatic data alongside SSI outcomes. Adult surgical patients across general, visceral, transplant, and other surgical disciplines in settings with variable ambient climate conditions. Most applicable to elective and semi-elective procedures where scheduling flexibility exists.
Abstract
OBJECTIVES: The impact of climate change on health is well recognised, yet its influence on postoperative complications remains underexplored. This systematic review examines how climatic factors-particularly temperature, humidity and seasonal variations-affect surgical outcomes. DESIGN: Systematic review with narrative synthesis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. DATA SOURCES: A comprehensive search of PubMed, Web of Science and the Cochrane Library from June 2015 to June 2025 was conducted. An additional supplementary PubMed search was performed to identify further relevant studies. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Included were studies published in English or German that examined associations between climatic factors, including temperature, humidity, precipitation or seasonality and postoperative outcomes in surgical patients. Studies without a surgical or climatic focus, animal studies, reviews and commentaries were excluded. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently screened studies and extracted data using predefined criteria. Risk of bias was assessed using the Newcastle-Ottawa Scale. Due to methodological heterogeneity, findings were synthesised narratively. RESULTS: Fifteen studies were included. High ambient temperatures were frequently associated with increased risks of surgical site infections (SSIs). Some large studies reported that even a one-degree rise significantly elevated infection rates. Humidity was also linked to higher infection rates, with evidence suggesting an independent effect in some cases. Seasonal changes influenced complication rates across regions and surgical disciplines, with infection and pneumonia peaks in summer or winter months. A few studies reported increased risks during heavy rainfall or institutional transitions such as the 'July effect'. CONCLUSION: Overall, elevated temperature and humidity appear to be associated with increased postoperative risks, especially SSIs. Seasonal patterns may further influence outcomes depending on geography and procedure type. While the available evidence supports a link between climate and surgical complications, methodological differences and limited adjustment for confounders highlight the need for more rigorous studies.
References
- 1.Schnoell, E., Monteiro, E., Stiegler, P., Sucher, R., & Bogner, A. (2026). Impact of climatic variables on postoperative outcomes in various surgical disciplines: a systematic review. BMJ Open. https://doi.org/10.1136/bmjopen-2026-116818
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