COVID-19 in Parkinson's disease: what holds the key?

Introduction: Parkinson's disease (PD) is more frequent in the elderly and increases the risk of respiratory infections. Previous data on PD and SARS-CoV-2 are scarce, suggesting a poor prognosis in advanced disease and second-line therapies.

Methods: A retrospective case-control study comparing patients with PD and COVID-19 and patients with PD without COVID-19 was conducted during the pandemic period in Spain (March 1st-July 31st 2020) in a tertiary university hospital.

Results: Thirty-nine (COVID-19 +) and 172 (COVID-19-) PD patients were included. Fifty-nine percent were males in both groups, with similar age (75.9 ± 9.0 COVID-19 + , 73.9 ± 10.0 COVID-19-), disease duration (8.9 ± 6.2 COVID-19 + , 8.5 ± 5.6 COVID-19-) and PD treatments. COVID-19 was mild in 10 (26%), required admission in 21 (54%) and caused death in 8 (21%) patients. Dementia was the only comorbidity more frequent in COVID-19 + patients (36% vs. 14%, p = 0.0013). However, in a multivariate analysis, institutionalization was the only variable associated with COVID-19 + (OR 17.0, 95% CI 5.0-60.0, p < 0.001). When considering severe COVID-19 (admission or death) vs. mild or absent COVID-19, institutionalization, neoplasm, dementia and a lower frequency of dopamine agonists were associated with severe COVID-19. In multivariate analysis, only institutionalization [OR 5.17, 95% CI 1.57-17, p = 0.004] and neoplasm [OR 8.0, 95%CI 1.27-49.8, p = 0.027] remained significantly associated.

Conclusion: In our experience, institutionalization and oncologic comorbidity, rather than PD-related variables, increased the risk of developing COVID-19, and impacted on its severity. These findings suggest that epidemiologic factors and frailty are key factors for COVID-19 morbidity/mortality in PD. Appropriate preventive strategies should be implemented in institutionalized patients to prevent infection and improve prognosis.