Diabetes Progression and Its Impact on Kidney Cancer Risk: Insights From a Longitudinal Korean Cohort Study

CONTEXT: The incidence of kidney cancer is rising in Korea, with lifestyle and metabolic factors such as smoking, obesity, and hypertension contributing to this trend. OBJECTIVE: This study assessed the relationship between diabetes progression and kidney cancer risk. METHODS: Using data from the National Health Information Database in South Korea, analyzing 2 365 294 patients with type 2 diabetes mellitus who underwent health examinations in 2015 and 2016, excluding those with pre-existing cancer or who died within a year. Patients were monitored until 2022 to determine the incidence of kidney cancer, defined by ICD-10 code C64. Diabetes progression was assessed using a scoring system (range 0-6) based on the number of oral glucose-lowering drugs (GLDs), diabetes duration, insulin use, and the presence of chronic kidney disease (CKD), diabetic retinopathy (DR), or cardiovascular disease. RESULTS: Among the indicators of diabetes progression, prolonged diabetes duration and the presence of CKD or DR were linked to higher hazard ratios (HRs) for kidney cancer. The risk of kidney cancer increased progressively with higher diabetes progression scores. Compared to participants with a score of 0, the adjusted HRs for kidney cancer were 1.21 (95% CI 1.13-1.30) for a score of 1, 1.28 (1.18-1.38) for a score of 2, 1.37 (1.23-1.51) for a score of 3, and 1.73 (1.49-2.01) for scores of 4 or higher. CONCLUSION: Diabetes progression is strongly associated with an increased risk of kidney cancer. These findings underscore the importance of targeted screening and awareness programs for kidney cancer in individuals with advanced diabetes.