Abstract
Background:
Preoperative comorbidities are known to be significant determinants of the postoperative outcomes of patients undergoing colorectal surgery. Conditions such as diabetes mellitus, hypertension, chronic kidney disease (CKD) and obesity are becoming more prevalent and may have an important impact on postoperative morbidity and mortality. However, the relative impact of these conditions continues to be inconsistently reported from study to study.
Objectives:
To systematically assess and quantify the influence of preoperative diabetes mellitus, hypertension, chronic kidney disease and obesity on postoperative morbidity and mortality in adults undergoing colorectal surgery.
Methods:
A systematic review and meta-analysis was conducted according to PRISMA 2020 guidelines. Electronic databases and pertinent literature were screened for observational studies assessing the link between preoperative comorbidities and postoperative results in colorectal surgery. Any studies that reported extractable estimates of the effect (odds ratios [OR], risk ratios [RR], or event data) were eligible in the meta-analysis. Pooled effect estimates for postoperative morbidity and mortality were calculated by using a random-effects model. Heterogeneity was measured by the I2 test statistic.
Results:
A total of 11 studies were included in the systematic review, with 7 meeting the criteria for quantitative synthesis. Diabetes mellitus was associated with a higher likelihood of both postoperative morbidity (OR 1.24, 95% CI 1.10–1.40) and mortality (OR 1.32, 95% CI 1.08–1.61). A similar pattern was observed for hypertension, although the effect size was smaller, with modest increases in morbidity (OR 1.18, 95% CI 1.05–1.32) and mortality (OR 1.21, 95% CI 1.02–1.43). Chronic kidney disease showed the strongest association with adverse outcomes, contributing to increased postoperative morbidity (OR 1.46, 95% CI 1.18–1.81) as well as mortality (OR 1.72, 95% CI 1.30–2.28). In contrast, obesity was not significantly associated with either postoperative morbidity (OR 1.02, 95% CI 0.90–1.16) or mortality (OR 0.94, 95% CI 0.78–1.13). Across analyses, heterogeneity was moderate, with I² values ranging from 36% to 51%.
Conclusion:
Preoperative comorbidities have a strong impact on the postoperative outcome in colorectal operations. CKD and diabetes mellitus are strong predictors of increased morbidity and mortality, whereas hypertension has moderate impact. Obesity does not seem to have a significant negative effect, supporting the concept of an "obesity paradox." The findings indicate the significance of preoperative risk stratification and optimization of high-risk patients.