OBJECTIVES: Continued morbidity following Coronavirus disease 2019 (COVID-19) (long COVID (LC)) is defined by the World Health Organization (WHO) as conditions lasting > 2 months and identified ~ 3 months after onset of COVID-19. The prevalence of LC is still unknown. Our study is designed to evaluate duration of COVID-19-related care, and prevalence of LC, in patients with mild, moderate and severe disease.

METHODS: Patients with COVID-19 (first date = index) from April 1, 2020 onwards, with ≥ 6 months of continuous enrollment pre- and post-index, in IBM® MarketScan® Commercial Claims and Encounters (CCAE) and Medicare Supplemental databases, were identified and stratified based on severity of disease (mild, moderate and severe/critical). Variables for all patients included demographics, comorbidities (Elixhauser index (EI) and all 31 Elixhauser disease domains), and distinct COVID-19 signs and symptoms. The main outcome was duration of disease, which was defined as follows: from 5 days before positive test to last related visit/prescription. A maximum gap of 35 days between visits/prescription was established to ensure that new conditions, not related to the index COVID-19 disease, were not categorized as continuation of COVID-19. LC was defined as duration ≥ 5 months.

RESULTS: 124,210 mild cases [age: 37.4, standard deviation (SD): 16.8 – 44.8% male, EI (SD) 0.63 (1.08)], 146,291 moderate cases [age: 41.7 (SD: 16.2), 43.2% male, EI (SD) 0.91 (1.35)] and 19,776 severe cases [age: 54.5 (SD: 14.9), 56.5% male, EI (SD) 1.88 (2.15)] were included. Excluding patients with LC, duration of disease averaged 20.4 days (SD: 25.08) for mild, 31.25 days (SD: 31.73) for moderate and 53.30 (SD: 36.85) for severe. LC affected 1.8% mild, 4.9% moderate and 13.7% severe cases, and exceeded 200 days.