Statin use and risk of colorectal cancer in patients with inflammatory bowel disease

Background Statin use has been linked to a reduced risk of advanced colorectal adenomas, but its association with colorectal cancer (CRC) in patients with inflammatory bowel disease (IBD) - a high risk population for CRC - remains inconclusive. Methods From a nationwide IBD cohort in Sweden, we identified 5273 statin users and 5273 non-statin users (1:1 propensity score matching) from July 2006 to December 2018. Statin use was defined as the first filled prescription for >= 30 cumulative defined daily doses and followed until December 2019. Primary outcome was incident CRC. Secondary outcomes were CRC-related mortality and all-cause mortality. Cox regression estimated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). Findings During a median follow-up of 5.6 years, 70 statin users (incidence rate (IR): 21.2 per 10,000 person-years) versus 90 non-statin users (IR: 29.2) were diagnosed with incident CRC (rate difference (RD), -8.0 (95% CIs: -15.8 to -0.2 per 10,000 person-years); aHR = 0.76 (95% CIs: 0.61 to 0.96)). The benefit for incident CRC was durationdependent in a nested case-control design: as compared to short-term use (30 days to <1 year), the adjusted odd ratios were 0.59 (0.25 to 1.43) for 1 to <2 years of use, 0.46 (0.21 to 0.98) for 2 to <5 years of use, and 0.38 (0.16 to 0.86) for >= 5 years of use (P (for tread) = 0.016). Compared with non-statin users, statin users also had a decreased risk for CRC-related mortality (IR: 6.0 vs. 11.9; RD, -5.9 (-10.5 to -1.2); aHR, 0.56 (0.37 to 0.83)) and all-cause mortality (IR: 156.4 vs. 231.4; RD, -75.0 (-96.6 to -53.4); aHR, 0.63 (0.57 to 0.69)). Interpretation Statin use was associated with a lower risk of incident CRC, CRC-related mortality, and all-cause mortality. The benefit for incident CRC was duration-dependent, with a significantly lower risk after >= 2 years of statin use. Funding This research was supported by Forte (i.e., the Swedish Research Council for Health, Working Life and Welfare). Copyright (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).