Analysis of the Incidence of Type 2 Diabetes, Requirement of Insulin Treatment, and Diabetes-Related Complications among Patients with Cancer

SIMPLE SUMMARY: Previous epidemiological studies have shown that type 2 diabetes may be associated with an increased risk of several cancer types and cancer-related mortality. However, whether cancer causes an increased risk of developing type 2 diabetes or its related complications remains unclear. The objective of this research was to investigate the risk of type 2 diabetes development, insulin requirements, and diabetes-related complications in patients with cancer. We found that cancer was associated with an increased risk of developing type 2 diabetes. Moreover, the number of new cases that required insulin was significantly higher in patients with cancer than in those without. Although there was no significant difference in the incidence of diabetes-associated complications between the two groups, some cancer types were associated with an increased risk of developing diabetic nephropathy. The findings suggest that clinicians should monitor the development of type 2 diabetes and its related morbidities in patients with cancer. ABSTRACT: This retrospective nationwide population-based cohort study used a dataset collected from the Korean National Health Insurance Service. We evaluated incident type 2 diabetes, insulin requirements, and diabetes-associated complications during a 10-year follow-up period using the log-rank test and Cox proportional hazards regression models. In total, 8114 and 16,228 individuals with and without cancer, respectively, were enrolled. We found a higher incidence rate and an increased adjusted hazard ratio (HR) for new cases of type 2 diabetes in patients with cancer, compared with those without cancer. Additionally, patients with cancer had a higher risk of insulin requirement than patients without cancer (adjusted HR 1.43, 95% confidence interval [CI], 1.14–1.78). Although there was no significant association between diabetes-associated complications and overall cancer diagnosis, specific cancer types (pancreas, bladder, and prostate) showed an increased risk of subsequent diabetic nephropathy. Therefore, clinicians should closely monitor patients with cancer for the early detection of type 2 diabetes and related morbidities.