Changes in fatigue of Parkinson's disease during the recurrent COVID-19 pandemic: Findings from the longitudinal analysis of the PHASE study.

Background: According to Japanese law, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the COVID-19 pandemic falls under Category 2, implying that it necessitates hospitalization, isolation, and significant government participation. The category of infection was lowered to Category 5 in May 2023, meaning that individuals were going back to live their lives as they did before the COVID-19 pandemic. This study aimed to explore changes in the prevalence of non-motor symptoms over a longer four-year period, spanning before and after the COVID-19 pandemic.

Methods: We conducted a questionnaire survey between January and February in the following years: 2021, 2022, 2023, and 2024.

Results: The Parkinson's fatigue scale score in 2021 (mean: 35.3) increased significantly in 2022 (49.84), 2023 (49.33), and 2024 (54.71) (p < 0.001). After adjusting for baseline score using a mixed linear model with random intercept, the Parkinson's fatigue scale was significantly increased by 15.9 points (95 % CI: 10.9 to 20.9) in 2022, 13.1 points (7.9-18.3) in 2023, and 16.9 points (11.3-22.6) in 2024 independently of all potential confounders including other non-motor symptoms.

Conclusions: The four years of longitudinal observation during the recurrent COVID-19 pandemic revealed that patients with PD experienced an increase in fatigue. Now, post-COVID-19 fatigue is attracting attention; however, the severity of fatigue may have already deteriorated during the period of recurrent COVID-19 pandemic.