Glucose tolerance and mortality across 24 cancer types and stages: A K-CURE Nationwide registry study

Aim: To evaluate the association between baseline glycemic status and mortality among patients with cancer and to examine whether these associations differ by stage and cancer type. Materials and Methods: We performed a nationwide cohort study using the Korean Cancer Public Library Database (K-CURE), which integrates national cancer registry, health screening, and cause-of-death records. A total of 671 366 adults newly diagnosed with one of 24 cancers between 2013 and 2019 were classified as normal glucose tolerance (NGT), impaired fasting glucose (IFG), or diabetes mellitus (DM). Multivariable Cox proportional hazards models estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for all-cause, cancer-specific, cardiovascular, and respiratory mortality. Analyses were stratified by Surveillance, Epidemiology, and End Results stage and cancer type, with sensitivity analyses applying 1-, 3-, and 5-year lag periods. Results: Over a mean follow-up of 3.5 years, 171 104 deaths occurred. Compared with NGT, DM was associated with higher risks of all-cause (HR 1.34, 95% CI 1.32–1.35), cancer-specific (HR 1.31, 95% CI 1.30–1.33), cardiovascular (HR 1.46, 95% CI 1.35–1.58), and respiratory mortality (HR 1.43, 95% CI 1.30–1.56). IFG was associated with modestly increased risks of all-cause (HR 1.06, 95% CI 1.05–1.08) and cancer-specific mortality (HR 1.07, 95% CI 1.05–1.08). Stage-stratified analyses demonstrated the strongest associations in localised cancers with attenuation in advanced stages. Conclusions: DM and IFG were linked to poorer survival after cancer diagnosis, with the greatest impact in early-stage disease. These findings support integrating metabolic risk assessment and management into survivorship care.