Mortality following recovery from COVID-19 hospitalization: a long-term cohort study

Background The COVID-19 pandemic has profoundly affected public health worldwide. Although research shows that COVID-19's health effects can persist for up to two years, the long-term impact on mortality in patients who survived the acute phase remains unclear. We investigated the association between COVID-19 hospitalization and all-cause mortality up to 3.5 years in these patients. Methods The study included Clalit Health Services members aged 40 years or older. The case group comprised members hospitalized due to COVID-19 between March 2020 and December 2021. Controls who did not contract COVID-19 during this period were matched at a 1:1 ratio based on birth year, sex, and Charlson comorbidity score. Follow-up began 30 days after discharge from the last COVID-19 hospitalization and ended on 30 September 2023, or upon all-cause mortality, whichever occurred first. Data were analyzed using Kaplan-Meier curves and multivariable frailty Cox regression models. Stratification was performed by age groups 40–64 years and 65 years or older. Results The incidence of all-cause mortality was higher compared to controls (4.91 vs. 2.63 per 1,000 participants, respectively), with a hazard ratio (HR) of 1.69 (95% CI, 1.57–1.83). Among patients aged 40–64, the HR for mortality was higher than in those aged 65+, at 2.31 (1.79–2.98) compared to 1.63 (1.50–1.76), respectively. Conclusions The study demonstrates that patients who have survived COVID-19 hospitalization have an elevated risk of all-cause mortality up to 3.5 years. In light of these findings, it is crucial to consider initiating follow-up for individuals hospitalized due to COVID-19, particularly those in the 40–64 age group, to address their ongoing health needs adequately.