Impact of COVID-19 and non-COVID-19 hospitalised pneumonia on longer term cardiovascular mortality in people with type 2 diabetes: A nationwide prospective cohort study from Scotland

Objective: This study examines if hospitalised COVID-19 pneumonia increases long-term cardiovascular mortality more than other hospitalised pneumonias in people with type 2 diabetes and aims to quantify the relative cardiovascular disease (CVD) mortality risks associated with COVID-19 versus non-COVID-19 pneumonia.

Research Design and Methods: Using the SCI-Diabetes register, two cohorts were identified: people with type 2 diabetes in 2016 and at the 2020 pandemic onset. Hospital and death records were linked to determine pneumonia exposure and CVD deaths. Poisson regression estimated hazard ratios (HR) for CVD death associated with both pneumonia types, adjusted for confounders. The median follow-up was 1461 days (2016 cohort) and 700 days (2020 cohort).

Results and Conclusions: The adjusted HR for CVD death following non-COVID-19 pneumonia was 5.51 (95% CI 5.31-5.71) pre-pandemic and 7.3 (95% CI 6.86-7.76) during the pandemic. For COVID-19 pneumonia, the

HR was 9.13 (95% CI 8.55-9.75). Beyond 30 days post-pneumonia, the HRs converged to 4.24 (95% CI 3.90-4.60), for non-COVID-19 and 3.35 (95% CI 3.00-3.74) for COVID-19 pneumonia, consistent even when excluding prior CVD cases. Hospitalised pneumonia, irrespective of causal agent, marks an increased risk for CVD death immediately and over the long term. COVID-19 pneumonia poses a higher CVD death risk than other pneumonias in the short term, but this distinction diminishes over time. These insights underscore the need for including pneumonia in CVD risk assessments, with particular attention to the acute impact of COVID-19 pneumonia.