Risk of SARS-CoV-2 infection, hospitalization, and death for COVID-19 in people with Parkinson disease or parkinsonism over a 15-month period: A cohort study

Background and purpose: The patterns of long-term risk of SARS-CoV-2 infection, hospitalization for COVID-19, and related death are uncertain in people with Parkinson disease (PD) or parkinsonism (PS). The aim of the study was to quantify these risks compared to a control population cohort, during the period March 2020–May 2021, in Bologna, Northern Italy. Methods: ParkLink Bologna cohort (759 PD, 192 PS) and controls (9226) anonymously matched (ratio = 1:10) for sex, age, district, and comorbidity were included. Data were analysed in the whole period and in the two different pandemic waves (March–May 2020 and October 2020–May 2021). Results: Adjusted hazard ratio of SARS-CoV-2 infection was 1.3 (95% confidence interval [CI] = 1.04–1.7) in PD and 1.9 (95% CI = 1.3–2.8) in PS compared to the controls. The trend was detected in both the pandemic waves. Adjusted hazard ratio of hospitalization for COVID-19 was 1.1 (95% CI = 0.8–1.7) in PD and 1.8 (95% CI = 0.97–3.1) in PS. A higher risk of hospital admission was detected in PS only in the first wave. The 30-day mortality risk after hospitalization was higher (p = 0.048) in PS (58%) than in PD (19%) and controls (26%). Conclusions: Compared with controls, after adjustment for key covariates, people with PD and PS showed a higher risk of SARS-CoV-2 infection throughout the first 15 months of the pandemic. COVID-19 hospitalization risk was increased only in people with PS and only during the first wave. This group of patients was burdened by a very high risk of death after infection and hospitalization.