Prevalence of comorbidities and their association with disease severity and mortality in COVID-19 patients: A systematic review and meta-analysis.

Background: Comorbidity among coronavirus disease-19 (COVID-19) patients contributes to increasing their susceptibility to severe illness. The objectives of this systematic review and meta-analysis were to assess the prevalence of comorbidities and their association in increased severity of disease and mortality in COVID-19 patients.

Methods: A thorough search of the literature was conducted using PubMed, Google Scholar, and other sources to include pertinent studies. Two independent authors extracted pertinent data using Microsoft Excel and exported it to Stata version 17 for meta-analysis. This review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Heterogeneity was assessed through I² statistics, subgroup analysis for categorical variables, and meta-regression for continuous variables. Publication bias was assessed through funnel plot and Egger statistics. Furthermore, a meta-analysis was performed using a random-effects model to estimate the pooled odds ratio (OR) with 95% CI, which was used to assess the association between comorbidity and severity and/or mortality of COVID-19.

Results: A total of 62 studies with 611,646 patients were included. The pooled prevalence of comorbidity among COVID-19 was 53.9% (95% CI: 48.4-59.3). Comorbidity was significantly associated with severity of COVID-19. Specifically, hypertension (OR: 1.09; 95% CI: 1.03-2.51), diabetes mellitus (OR: 1.29; 95% CI: 1.07-1.56), and obesity (OR: 1.61; 95% CI: 1.46-1.76) significantly increased the odds of severe COVID-19. Furthermore, hypertension (OR: 1.14; 95% CI: 1.02-1.57), diabetes mellitus (OR: 1.39; 95% CI: 1.17-1.65), obesity (OR: 1.24; 95% CI: 1.15-1.32), chronic kidney diseases (OR: 1.62; 95% CI: 1.25-2.09), and chronic obstructive pulmonary diseases (COPD) (OR: 1.23; 95% CI: 1.15-1.32) were significantly associated with mortality of COVID-19 patients.

Conclusion: The pooled prevalence of comorbidity among COVID-19 was found slightly higher than that reported in previous systematic reviews, which ranged from 40.0% to 41.1%. Comorbidity increased the odds of severe COVID-19. Participants with hypertension, obesity, or diabetes mellitus had significantly increased odds of severe COVID-19. There is a need to have close follow-up of COVID-19 patients who have comorbidity.

Protocol registration: This systematic review and meta-analysis study was registered under the registration number CRD42023493170.