Incidence and Determinants of Post-Coronavirus Disease Syndrome by Disease Severity: An Ambispective Cohort Study from a Tertiary Care Hospital in Puducherry

Abstract

Post-coronavirus disease 2019 (COVID-19) condition, or long COVID, persists beyond the acute phase, impacting quality of life. This study estimated the incidence and determinants of post-COVID syndrome (PCS) in Puducherry, India. This ambispective cohort study from May to December 2022 included 1162 adults with COVID-19. Participants were stratified by disease severity (moderate/severe and mild) based on clinical parameters during acute illness. We conducted follow-ups at 1, 3, 6, and 12 months. PCS was defined as having ≥two of five common symptoms (fatigue, joint/muscle pain, breathing difficulty, loss of smell/taste, or sleep problems). Relative risks (RR) and 95% confidence intervals (CI) were estimated using binomial regression with a Poisson link, adjusting for socio-demographic and clinical factors. Incidence of PCS was consistently higher in the moderate/severe group. At 1, 3, 6, and 12 months, incidence was 65.6%, 37.7%, 24.4%, and 34.4% for moderate/severe cases, and 24.3%, 11.0%, 7.1%, and 16.9% for mild cases, respectively. Moderate/severe cases had significantly higher RR of 2.70 at 1 month (95% CI: 2.31–3.15), 3.42 at 3 months (95% CI: 2.65–4.40), 3.46 at 6 months (95% CI: 2.49–4.80), and 2.04 at 12 months (95% CI: 1.65–2.52), all P < 0.001. Independent risk factors for PCS included rural residence, comorbidities, complications during hospitalization, and age over 30 years. Moderate/severe COVID-19 severity and specific socio-demographic and clinical factors were associated with an elevated risk of PCS. Early identification and targeted follow-up are recommended to mitigate long-term impacts.