Colorectal Cancer and Subsequent Diabetes Risk: A Population-based Cohort Study in Taiwan

Abstract Context The association between colorectal cancer (CRC) and new-onset diabetes mellitus remains unclear. Objective To examine the association between CRC and the risk of subsequent diabetes mellitus and to further investigate the impact of chemotherapy on diabetes mellitus risk in CRC. Methods In this nationwide cohort study using the Taiwan Cancer Registry database (2007-2018) linked with health databases, 86 268 patients with CRC and an equal propensity score-matched cohort from the general population were enrolled. Among them, 37 277 CRC patients from the Taiwan Cancer Registry (2007-2016) were analyzed for diabetes mellitus risk associated with chemotherapy. Chemotherapy exposure within 3 years of diagnosis was categorized as no chemotherapy, < 90 days, 90 to 180 days, and > 180 days. Differences in diabetes mellitus risk were assessed across these categories. Results Each group involved 86 268 participants after propensity score matching. The patients with CRC had a 14% higher risk of developing diabetes mellitus than the matched general population (hazard ratio [HR]: 1.14; 95% CI, 1.09-1.20). The highest risk was observed within the first year after diagnosis, followed by a sustained elevated risk. Long-term chemotherapy (> 180 days within 3 years) was associated with a 60% to 70% increased risk of subsequent diabetes mellitus (HR: 1.64; 95% CI, 1.07-2.49). Conclusion Patients with CRC are associated with an elevated risk of diabetes mellitus, and long-term chemotherapy, particularly involving capecitabine, increases diabetes mellitus risk. Thus, monitoring blood glucose levels is crucial for patients with CRC, especially during extended chemotherapy.