Protective effects of 23‐valent pneumococcal polysaccharide vaccination against mortality among elder patients with type 2 diabetes mellitus

BACKGROUND: Older adults with type 2 diabetes mellitus are at elevated risk for severe pneumococcal disease, experiencing higher rates of complications and mortality. However, the evidence for the protective benefits of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) against mortality in this demographic remains limited. METHODS: This retrospective study included 8649 elderly people with type 2 diabetes mellitus in Soochow, China, comprising 3247 PPSV23-vaccinated individuals and 5402 unvaccinated patients. Cox proportional hazards analyses were performed to calculate the adjusted hazard ratios (HRs) of the association between PPSV23 vaccination and the risk of all cause mortality, pneumonia-related mortality, cardiovascular disease-related mortality and cancer mortality. Inverse probability weighting (IPW) was applied to estimate the average treatment effect (ATE) of universal PPSV23 vaccination compared to unvaccinated. RESULTS: During the follow-up period, a total of 1557 deaths were recorded. Compared to unvaccinated elderly people with type 2 diabetes mellitus, those receiving PPSV23 vaccine exhibited significantly lower risks of all-cause mortality (HR: 0.47; 95% CI: 0.42-0.53), with reductions also observed in deaths related to cardiovascular disease (HR: 0.50; 95% CI: 0.41-0.62), pneumonia (HR: 0.62; 95% CI: 0.43-0.89) and cancer (HR: 0.54; 95% CI: 0.42-0.70). Furthermore, IPW estimates indicated that universal PPSV23 vaccination among the elderly people with type 2 diabetes mellitus could prevent an average of 11.4% of all-cause deaths (p < 0.001), 4.0% of cardiovascular disease-related deaths (p < 0.001), 0.8% of pneumonia-related deaths (p = 0.005) and 1.9% of cancer deaths (p < 0.001). CONCLUSIONS: PPSV23 vaccination is associated with a reduced risk of all cause mortality, cardiovascular disease-related mortality, pneumonia-related mortality and cancer mortality in elderly people with type 2 diabetes mellitus.