Risk factors associated with development and persistence of long COVID

BackgroundLong COVID has been a social concern. Though patient characteristics associated with developing long COVID are partially known, those associated with persisting it have not been identified. MethodsWe 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 the presence and duration of long COVID were obtained. We identified factors associated with development and persistence of long COVID using multivariate logistic and linear regression analysis, respectively. ResultsWe analyzed 457 of 526 responses (response rate, 86.9%). The median age was 47 years, and 378 patients (84.4%) had mild disease in 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 (OR 2.03, 95% 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 were at risk 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). ConclusionWe identified risk factors for the persistence as well as development of long COVID. Many patients suffer from long-term residual symptoms, even in mild cases. SummaryOur cross-sectional questionnaire survey of patients recovering from COVID-19 revealed that women, young age, and low body mass index were risk factors for the development of multiple symptoms, and that even mild cases of COVID-19 suffered from long-term residual symptoms.