We aimed to determine the characteristics, risk factors, and outcomes associated with readmission in COVID-19 patients.

PubMed, Embase, Web of Science, and Scopus databases were searched to retrieve articles on readmitted COVID-19 patients, available up to September 25, 2021. All studies comparing characteristics of readmitted and non-readmitted COVID-19 patients were included. We also included articles reporting the reasons for readmission in COVID-19 patients. Data were pooled and meta-analyzed using random or fixed-effect models, as appropriate. Subgroup analyses were conducted based on the place and duration of readmission.

Our meta-analysis included 4823 readmitted and 63,413 non-readmitted COVID-19 patients. The re-hospitalization rate was calculated at 9.3% with 95% Confidence Interval (CI) [5.5%–15.4%], mostly associated with respiratory or cardiac complications (48% and 14%, respectively). Comorbidities including cerebrovascular disease (Odds Ratio (OR) = 1.812; 95% CI [1.547–2.121]), cardiovascular (2.173 [1.545–3.057]), hypertension (1.608 [1.319–1.960]), ischemic heart disease (1.998 [1.495–2.670]), heart failure (2.556 [1.980–3.300]), diabetes (1.588 [1.443–1.747]), cancer (1.817 [1.526–2.162]), kidney disease (2.083 [1.498–2.897]), chronic pulmonary disease (1.601 [1.438–1.783]), as well as older age (1.525 [1.175–1.978]), male sex (1.155 [1.041–1.282]), and white race (1.263 [1.044–1.528]) were significantly associated with higher readmission rates (P < 0.05 for all instances). The mortality rate was significantly lower in readmitted patients (OR = 0.530 [0.329–0.855], P = 0.009).

Male sex, white race, comorbidities, and older age were associated with a higher risk of readmission among previously admitted COVID-19 patients. These factors can help clinicians and policy-makers predict, and conceivably reduce the risk of readmission in COVID-19 patients.