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

Background: 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 on debate, due to conflicting evidence emerged from different observational studies. Objective: We performed a systematic review with meta-analysis to assess the clinical outcome in SOT recipients with COVID-19 compared to general population. Data source: PubMed-MEDLINE and Scopus were independently searched until 13 October 2021. Study eligibility criteria: Prospective or retrospective observational studies comparing clinical outcome in SOT recipients versus general populations affected by COVID-19. Primary endpoint was 30-day mortality. Participants: Patients with confirmed COVID-19. Intervention: Solid organ transplant recipients. Assessment of risk of bias: Quality of included studies was independently assessed according to ROBINS-I tool for observational studies. Methods of data synthesis: Meta-analysis was performed by pooling odds ratio (OR) retrieved from studies providing adjustment for confounders using a random-effect model with inverse variance method. Multiple subgroup and sensitivity analyses were conducted to investigate source of heterogeneity. Results: 3,501 articles were screened, and thirty-one observational studies (N=590,375; 5,759 SOT recipients vs. 584,616 general population) were included in the meta-analyses. No difference in 30-day mortality rate was found in primary analysis including studies providing adjustment for confounders (N=17; 3,752 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. Higher risk of ICU 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. Conclusions: No increased risk in mortality was found in SOT recipients affected by COVID-19 compared to general population when adjusted for demographic and clinical features and COVID-19 severity.