Assessing the impact of chronic respiratory diseases on COVID-19 in-hospital mortality in the Italian population: a comparative study.

The COVID-19 pandemic has severely impacted Italy, leading to millions of cases and high mortality rates. Pre-existing chronic respiratory diseases may influence patient outcomes, and understanding their role is essential for improving healthcare strategies during such crises. This study analysed data from the Italian hospital discharge records database to explore the association between chronic respiratory diseases and in-hospital mortality due to COVID-19. Patients hospitalized in 2020 were studied, with exposure to respiratory diseases assessed based on hospitalizations between 2010 and 2019. Cox regression models were used to adjust for demographic and clinical factors, including age, gender, and comorbidity. Patients with pre-existing chronic respiratory diseases (n = 28 375, 13.9% of the total study population of 203 820) had a 71% higher risk (hazard ratio: 1.71, confidence interval: 1.54-1.90, P < .001) of in-hospital mortality compared to those without such conditions. Age, gender, the number of previous hospitalizations, and the Charlson comorbidity index were identified as key factors in mortality. Kaplan-Meier survival curves demonstrated significant differences in survival probabilities between exposed and unexposed groups across various age categories. Chronic respiratory diseases are associated with increased COVID-19 mortality, underscoring the need for targeted interventions in vulnerable populations to reduce the impact of future pandemics.