Effects of Metabolic Syndrome and Findings from Baseline Colonoscopies on Occurrence of Colorectal Neoplasms

Background & Aims Metabolic syndrome is associated with increased risk of colorectal neoplasm, but little is known about its effects on the occurrence of neoplasm after colonoscopy. We investigated the effects of metabolic syndrome on the risk of advanced neoplasm after colonoscopy. Methods We performed a prospective study of 4483 subjects age 50 years and older who underwent screening and surveillance colonoscopies as part of an annual health check-up at National Taiwan University Hospital. Baseline demographic data and colonoscopic findings were recorded. Subjects with either advanced adenoma or 3 or more adenomas detected at baseline were classified as high risk; those with fewer than 3 nonadvanced adenomas were classified as low risk; and those without any neoplastic lesions were classified as normal. The cumulative risk of detecting an advanced neoplasm during surveillance colonoscopies (3 and 5 years later) was correlated with risk group and metabolic syndrome. Hazard ratios (HRs) were calculated for occurrence of neoplasm according to baseline colonoscopic findings and clinical risk factors, including metabolic syndrome. Results Advanced neoplasms were detected during the surveillance colonoscopies in 1.3% of subjects in the normal group and in 2.4% of those in the low-risk group at 5 years, and in 8.5% of subjects in the high-risk group at 3 years. Subjects with metabolic syndrome had a significantly higher risk for subsequent advanced neoplasms ( P P P  = .04), but not in the high-risk group ( P  = .48). In Cox regression analysis, metabolic syndrome had significant effects on the risk for advanced neoplasms in the normal (HR, 2.07; 95% confidence interval, 1.13–3.81) and low-risk groups (HR, 2.34; 95% confidence interval, 1.01–5.41), but not in the high-risk group. Conclusions Metabolic syndrome is a significant risk factor for occurrence of an advanced adenoma after a negative or low-risk finding from a baseline colonoscopy. Metabolic syndrome should be considered in risk stratification for surveillance intervals.