Long‐Term Risk of Incident Type 2 Diabetes Following SARS‐CoV‐2 Infection: A Population‐Based Study in British Columbia, Canada

Aims To assess the long‐term risk of incident type 2 diabetes mellitus (T2DM) following SARS‐CoV‐2 infection in a large population‐based cohort. Materials and Methods We conducted a retrospective cohort study of all British Columbia residents aged ≥ 18 years tested for SARS‐CoV‐2 by reverse transcription polymerase chain reaction (RT‐PCR) between 1 January 2020 and 31 January 2024. Individuals with pre‐existing diabetes or residing in long‐term care were excluded. Incident T2DM, identified more than 30 days after testing, was ascertained using a validated administrative algorithm. Inverse probability‐weighted cause‐specific hazard models estimated adjusted hazard ratios (HRs) for incident diabetes, accounting for death as a competing risk. Subgroup analyses examined associations by sex, age, vaccination status, COVID‐19 severity, and follow‐up duration. Results Among 2,044,421 individuals (296,390 SARS‐CoV‐2‐positive; 1,748,031 negative), 47,704 (2.33%) incident T2DM cases were identified over a median follow‐up of 874 days. Compared with the SARS‐CoV‐2‐negative group, the risk of diabetes was higher among infected individuals (HR 1.18; 95% CI: 1.15–1.22; p < 0.0001), rising progressively with illness severity—from ambulatory to hospitalised and intensive‐care cases. No evidence of association was found among the vaccinated subgroups. The excess risk persisted for up to 3 years before waning thereafter. Conclusions SARS‐CoV‐2 infection was associated with an increased risk of incident T2DM that persisted for up to 3 years, particularly among unvaccinated and severely ill individuals. These findings highlight the importance of post‐infection metabolic surveillance and the potential protective role of vaccination.