Predictive characteristics of prolonged symptoms and seroconversion in ambulatory patients recovering from SARS-CoV-2 infection

Introduction: As an increasing number of patients present for ambulatory care following acute COVID-19, we set out to characterize and identify clinical predictors of prolonged symptoms and antibody seroconversion. We hypothesized that patients who present with a high symptom burden are more likely have prolonged post-acute sequelae of COVID-19 (PASC). Methods: All adults with confirmed SARS-CoV-2 infection evaluated at a single ambulatory center between April and September 2020 were studied retrospectively using a logit model and ANOVA; the importance of variables associated with prolonged symptoms and seroconversion was determined using machine learning methodology. Results: The most common initial symptoms of 276 subjects were fatigue, dyspnea, cough, fever, and myalgia, with ~30% experiencing all five. Those with prolonged sequelae (>4 weeks) reported higher initial symptom burden compared to those without PASC (mean 8.2 vs. 3.3 symptoms, p<0.0001). Anosmia (odds ratio, OR 23.0), myalgia (OR 12.8), and dyspnea (OR 10.8) had highest predictive values for prolonged sequelae. Neither lung function, nor pre-existing lung disease correlated with PASC pulmonary symptoms (p=0.17, p=0.5, respectively). Natural post-COVID-19 seroconversion rate was 78%, with male gender having higher and corticosteroid treatment and elevated creatinine having lower likelihood of seroconversion. Conclusion: Ambulatory PASC patients display a broad range of symptoms. A high initial symptom burden correlates with prolonged sequelae. In unvaccinated individuals, antibody seroconversion may be influenced by gender, corticosteroid use, and renal function.