Background: Long coronavirus disease (COVID) has been a social concern. Though patient characteristics associated with the development of long COVID are partially known, those associated with its persistence have not been identified. Methods: We conducted a cross-sectional questionnaire survey of patients after COVID-19 recovery who visited the National Center for Global Health and Medicine between February 2020 and March 2021. Demographic and clinical data and data regarding the presence and duration of long COVID were obtained. We identified factors associated with the development and persistence of long COVID using multivariate logistic and linear regression analysis, respectively. Results: We analyzed 457 of 526 responses (response rate, 86.9%). The median age was 47 years, and 378 patients (84.4%) had mild disease in the acute phase. The number of patients with any symptoms after 6 and 12 months after onset or diagnosis were 120 (26.3%) and 40 (8.8%), respectively. Women were at risk for development of fatigue (odds ratio [OR]: 2.03, 95% confidence interval [CI]: 1.31-3.14), dysosmia (OR: 1.91, 95% CI: 1.24-2.93), dysgeusia (OR: 1.56, 95% CI: 1.02-2.39), and hair loss (OR: 3.00, 95% CI: 1.77-5.09) and for persistence of any symptoms (coefficient: 38.0, 95% CI: 13.3-62.8). Younger age and low body mass index were risk factors for developing dysosmia (OR: 0.96, 95% CI: 0.94-0.98 and OR: 0.94, 95% CI: 0.89-0.99, respectively) and dysgeusia (OR: 0.98, 95% CI: 0.96-1.00 and OR: 0.93, 95% CI: 0.88-0.98, respectively). Conclusion: We identified risk factors for the development and persistence of long COVID. Many patients suffer from long-term residual symptoms, even in mild cases.
Risk Factors Associated with Development and Persistence of Long COVID: A Cross-Sectional Study (preprint)