Risk of breakthrough SARS‐CoV‐2 infection and clinical outcomes among vaccinated patients with type 2 diabetes

Abstract

AbstractAimTo explore the risk of breakthrough infection among patients with type 2 diabetes (T2D) and risk of severe clinical outcomes after SARS‐CoV‐2 infection according to vaccination status.Materials and MethodsWe conducted a population‐based cohort study using South Korea's linked database of nationwide COVID‐19 registry and claims data between 2018 and 2021. Hazard ratios (HRs) and 95% confidence intervals (CIs) for breakthrough infections were measured in 1:1 propensity‐score (PS)‐matched fully vaccinated patients with versus without T2D (full–vaccination cohort), and HRs for all‐cause mortality, intensive care unit (ICU) admission/mechanical ventilation (MV) use, and hospitalizations after SARS‐CoV‐2 infection were measured in 1:1 PS‐matched T2D patients with versus without full–vaccination (T2D cohort).ResultsAfter 1:1 PS matching, 2 109 970 patients with and without T2D were identified (age 63.5 years; 50.9% male). Patients with T2D showed an increased risk of breakthrough infections compared to those without T2D (HR 1.10, 95% CI 1.06‐1.14). The increased risk of breakthrough infections was more notable among T2D patients receiving insulin treatment. However, the risk of severe COVID‐19 outcomes was lower in fully vaccinated T2D patients compared with unvaccinated T2D patients (all‐cause mortality: HR 0.54, 95% CI 0.43‐0.67; ICU admission/MV use: HR 0.31, 95% CI 0.23‐0.41; hospitalization: HR 0.73, 95% CI 0.68‐0.78).ConclusionsWhile patients with T2D remain a vulnerable population to SARS‐CoV‐2 infection even after full‐vaccination, full‐vaccination was associated with a lower risk of adverse clinical outcomes after SARS‐CoV‐2 infection. These findings support the guidelines recommending patients with T2D as a priority vaccination group.