Post-COVID-19 Condition in Hospitalized Survivors After 1 Year of Infection During the Alpha- and Delta-variant Dominant Waves in Japan: COVID-19 Recovery Study II

Abstract

Background: Evidence of post-COVID-19 condition (PCC) in the Alpha- and Delta-variant dominant waves is limited.

Methods: In a nationwide multicenter cohort study in collaboration with 20 hospitals, we collected data using self-administered questionnaires and electronic medical records of participants aged 20 or more diagnosed with COVID-19, hospitalized between April 1, 2021 and September 30, 2021, and discharged alive. Descriptive statistics were analyzed for PCC and mental health (HADS anxiety and depression scores), comparing Alpha- and Delta-variant dominant waves.

Results: We analyzed 1,040 patients (median age, 57 [IQR 49–66] years; men, 66.2%). Of the respondents, 45.4% had at least one PCC symptom 1 year after infection. The common symptoms included dyspnea (20.7%), fatigue/malaise (17.6%), muscle weakness (15.4%), decrease in concentration (13.4%), and sleep disorder (13.3%), followed by brain fog (8.4%). Among patients with PCC, 14.0% had anxiety (HADS-Anxiety ≥11), and 18.6% had depression (HADS-Depression ≥11), with four times higher proportions than those without PCC; only small variations by age, sex, and waves were observed. Associated factors for PCC were age 40 years or over, women, severity of COVID-19 during hospitalization, ex-smokers who quit smoking before COVID-19 infection and being infected during the Delta-variant dominant wave.

Conclusion: The study described the prevalence of PCC, associated factors, and mental health of COVID-19 survivors hospitalized during the Alpha- and Delta-variant dominant waves in Japan. Further follow-up will be conducted to examine the longer-term impact of COVID-19 on PCC, complications, daily life, and socioeconomic status.