The objective of this observational, retrospective, multicenter cohort study was to compare the groups of Parkinson's Disease (PD) patients who were administered amantadine chronically and those who did not take this medication in the context of the incidence and severity of COVID-19 infection. The structured questionnaires were completed during the patient's follow-up visits at the Outpatient Clinic or during hospitalization. The questionnaire included the following information: patient's age, duration of PD, Hoehn-Yahr (H-Y) stage, comorbidities, medications, COVID-19 confirmed by reverse transcription polymerase chain reaction (RT-PCR) swab test for SARS-CoV-2 with specified symptoms and their severity (home or hospital treatment). The vaccination status was verified as well. Five hundred fifty-two (n = 552) patients participated in the study - 329 men (60%). The mean H-Y stage was 2.44 (range: 1-4) and the mean duration of PD was 9.6 years (range: 1-34). One hundred four subjects (19%) had confirmed COVID-19 infection. Subjects over 50 years of age had a significantly lower incidence of COVID-19 (17% vs 38%, p = 0.0001) with difference also in mean H-Y stage (2.27 vs 2.49; p = 0.011) and disease duration (8.4 vs 9.9 years, p = 0.007). There were no differences between patients with and without co-morbidities. In the whole analyzed group 219 (40%) subjects were treated with amantadine. Comparing COVID-19 positive and negative patients, amantadine was used by 48/104 (46%) and 171/448 (38%) respectively. 22% of patients on amantadine vs. 17% of patients without amantadine developed COVID-19. These differences were not significant. There were no differences in morbidity and severity of COVID-19 between amantadine users and non-users as well. The authors concluded that COVID-19 was less common in older (>50) with longer duration and more advanced patients. Amantadine did not affect the risk of developing COVID-19 or the severity of infection.
Przytuła F, Kasprzak J, Dulski J, Koziorowski D, Kwaśniak-Butowska M, Sołtan W, Roszmann A, Śmiłowska K, Schinwelski M, Sławek J. Morbidity and severity of COVID-19 in patients with Parkinson's disease treated with amantadine - A multicenter, retrospective, observational study. Parkinsonism Relat Disord. 2022 Dec 6;106:105238.