Risk factors for post-COVID-19 condition among previously hospitalized COVID-19 patients: a systematic review and meta-analysis

Abstract

Background Post-COVID-19 condition is a major source of long-term morbidity after SARS-CoV-2 infection. Patients hospitalized for COVID-19 may be at particularly high risk because hospitalization often reflects greater acute disease severity and comorbidity burden. However, evidence on risk factors in previously hospitalized populations remains inconsistent due to differences in outcome definitions, follow-up periods, and analytical approaches. This systematic review and meta-analysis aimed to identify risk factors associated with post-COVID outcomes among patients previously hospitalized for COVID-19. Methods A systematic review and meta-analysis was conducted following PRISMA 2020 principles. PubMed/MEDLINE, Scopus, Web of Science Core Collection, and the WHO COVID-19 Global Literature Database were searched for studies published between 1 January 2020 and 24 February 2026. Eligible studies included hospitalized patients with confirmed or probable COVID-19, assessed post-acute outcomes at least 4 weeks after acute infection, hospitalization, recovery, or discharge, and evaluated at least one candidate risk factor. Adjusted effect estimates were prioritized, and random-effects meta-analyses were performed when at least two comparable estimates were available. Results Eleven studies were included in the qualitative synthesis, and seven contributed to quantitative meta-analysis. Five risk-factor groups were pooled: female sex, acute disease severity or respiratory support, intensive care unit (ICU) admission, vaccination status, and hypertension. Female sex was associated with higher odds of post-COVID outcomes (OR 1.94, 95% CI 1.60–2.35; I2 = 6.9%). The strongest association was observed for greater acute disease severity or advanced respiratory support (OR 2.55, 95% CI 1.77–3.68; I2 = 13.0%). ICU admission (OR 1.88, 95% CI 1.24–2.83), no or incomplete vaccination (OR 1.90, 95% CI 1.33–2.72), and hypertension (OR 1.60, 95% CI 1.16–2.20) were also associated with increased odds. Additional predictors, including obesity, age, smoking, dysgeusia, symptom burden, and neurological or psychiatric comorbidity, were summarized narratively. Conclusion Among previously hospitalized COVID-19 patients, the most consistent risk factors for post-COVID outcomes were female sex, greater acute disease severity or respiratory support, ICU admission, no or incomplete vaccination, and hypertension. These findings support risk-based post-discharge follow-up, although the evidence remains limited by heterogeneous outcome definitions and the small number of studies available for several risk factors.