Effect of Comorbidities on the Mortality of Patients With COVID‐19: A Systematic Review of Reviews and Meta‐Analyses

Studies with strong scientific evidence have demonstrated that comorbidities are associated with fatal outcomes in patients with SARS-CoV-2 infection. To aggregate the findings of these studies and assess the magnitude of the effect of different chronic diseases on COVID-19 mortality, we conducted a systematic review of reviews and meta-analysis. Six databases were searched to retrieve systematic reviews with meta-analysis published during the early years of the pandemic. Statistical analysis was performed using Stata v.12.0 software, and the risk ratio (RR) and odds ratio (OR), with a confidence interval of 95% (95% CI), were calculated. We selected 15 publications with 476 original articles and 2,135,888 patients. Our results indicated the following risk factors for COVID-19 mortality: diabetes mellitus (RR = 1.95; 95% CI:1.41-2.49); hypertension (RR = 1.88; 95% CI:1.51-2.26); cancer (RR = 1.84; 95% CI:1.24-2.43); cardiovascular (RR = 2.14; 95% CI:1.66-2.63), cerebrovascular (RR = 2.43; 95% CI:2.15-2.72), kidney (RR = 2.39; 95% CI:1.36-3.42), pulmonary (RR = 1.98; 95% CI:1.48-2.47) and liver diseases (OR = 1.56; 95% CI:1.18-1.94); obesity (OR = 1.15; 95% CI:1.04-1.26); smoking habits (OR = 1.18; 95% CI:1.13-1.22); and the male sex (OR = 1.69; 95% CI:1.65-1.73). Evidence has confirmed that underlying chronic conditions, which involve an imbalance in the immune response, significantly increase the risk of COVID-19 deaths.