Factors associated with COVID‐19 in people with Parkinson’s disease: a systematic review and meta‐analysis

Background There is debate as to whether there is an increased risk of COVID‐19 infection in people with Parkinson's disease (PD), possibly due to associated factors. This study aimed to systematically review the factors associated with COVID‐19 in people with PD. Methods A search was carried out in PubMed, Scopus, and Web of Science up to November 2020 (updated until 1 April 2021). Observational studies that analyzed factors associated with COVID‐19 in people with PD were selected and revised. Results The authors included six studies (four case‐controlled studies and two cross‐sectional studies) in the qualitative and quantitative syntheses. The authors found that the following factors were associated with COVID‐19 in people with PD: obesity (OR: 1.79, 95% CI: 1.07–2.99, I2: 0%), any pulmonary disease (OR: 1.92, 95% CI: 1.17–3.15, I2: 0%), COVID‐19 contact (OR: 41.77, 95% CI: 4.77 – 365.56, I2: 0%), vitamin D supplementation (OR: 0.50, 95% CI: 0.30–0.83, I2: 0%), hospitalization (OR: 11.78, 95% CI: 6.27–22.12, I2: 0%), and death (OR: 11.23, 95% CI: 3.92–32.18, I2: 0%). The authors did not find any significant association between COVID‐19 and hypertension, diabetes, cardiopathy, cancer, any cognitive problem, dementia, chronic obstructive pulmonary disease, renal or hepatic disease, smoking, and tremor. Conclusions Meta‐analyses were limited by the number of events and some methodological limitations. Despite this, the authors assessed the available evidence, and the results may be useful for future health policies.