Clinical outcome in solid organ transplant recipients affected by COVID-19 compared to general population: a systematic review and meta-analysis

A significant increased risk of complications and mortality in immunocompromised patients affected by COVID-19 has been described. However, the impact of COVID-19 in solid organ transplant (SOT) recipients is an issue still under debate, due to conflicting evidence that has emerged from different observational studies. We performed a systematic review with a meta-analysis to assess the clinical outcome in SOT recipients with COVID-19 compared with the general population. PubMed-MEDLINE and Scopus were independently searched until 13 October 2021. Prospective or retrospective observational studies comparing clinical outcome in SOT recipients versus general populations affected by COVID-19 were included. The primary endpoint was 30-day mortality. Participants were patients with confirmed COVID-19. Interventions reviewed were SOTs. The quality of the included studies was independently assessed with the Risk of Bias in Non-randomized Studies of Interventions tool for observational studies. The meta-analysis was performed by pooling ORs retrieved from studies providing adjustment for confounders using a random-effects model with the inverse variance method. Multiple subgroups and sensitivity analyses were conducted to investigate the source of heterogeneity. A total of 3501 articles were screened, and 31 observational studies (N = 590 375; 5759 SOT recipients vs. 584 616 general population) were included in the meta-analyses. No difference in 30-day mortality rate was found in the primary analysis, including studies providing adjustment for confounders (N = 17; 3752 SOT recipients vs. 159 745 general population; OR: 1.13; 95% CI, 0.94–1.35; I2 = 33.9%). No evidence of publication bias was reported. A higher risk of intensive care unit admission (OR: 1.56; 95% CI, 1.03–2.63) and occurrence of acute kidney injury (OR: 2.50; 95% CI, 1.81–3.45) was found in SOT recipients. No increased risk in mortality was found in SOT recipients affected by COVID-19 compared with the general population when adjusted for demographic and clinical features and COVID-19 severity.