Global Diabetes Prevalence in COVID-19 Patients and Contribution to COVID-19- Related Severity and Mortality: A Systematic Review and Meta-analysis

Abstract

Background: COVID-19 and diabetes both contribute to large global disease burdens.

Purpose: To quantify the prevalence of diabetes in various COVID-19 disease stages and calculate the population attributable fraction (PAF) of diabetes to COVID-19-related severity and mortality.

Data sources: Systematic review identified 729 studies with 29,874,938 COVID-19 patients.

Study selection: Studies detailed the prevalence of diabetes in subjects with known COVID-19 diagnosis and severity.

Data extraction: Study information, COVID-19 disease stages, and diabetes prevalence were extracted.

Data synthesis: The pooled prevalence of diabetes in stratified COVID-19 groups was 14.7% (95% CI 12.5-16.9) among confirmed cases, 10.4% (7.6-13.6) among nonhospitalized cases, 21.4% (20.4-22.5) among hospitalized cases, 11.9% (10.2-13.7) among nonsevere cases, 28.9% (27.0-30.8) among severe cases, and 34.6% (32.8-36.5) among deceased individuals, respectively. Multivariate metaregression analysis explained 53-83% heterogeneity of the pooled prevalence. Based on a modified version of the comparative risk assessment model, we estimated that the overall PAF of diabetes was 9.5% (7.3-11.7) for the presence of severe disease in COVID-19-infected individuals and 16.8% (14.8-18.8) for COVID-19-related deaths. Subgroup analyses demonstrated that countries with high income levels, high health care access and quality index, and low diabetes disease burden had lower PAF of diabetes contributing to COVID-19 severity and death.

Limitations: Most studies had a high risk of bias.

Conclusions: The prevalence of diabetes increases with COVID-19 severity, and diabetes accounts for 9.5% of severe COVID-19 cases and 16.8% of deaths, with disparities according to country income, health care access and quality index, and diabetes disease burden.

Graphical abstract

Figure 1

Global prevalence of diabetes by geographical regions and other subgroups for various COVID-19 disease statuses. Prevalence shown by COVID-19 waves (A), WHO geographical regions (B), country income level (C), HAQ (D), diabetes background prevalence (E), undiagnosed diabetes proportion (F), IGT (G), and IFG (H). The color bars denote the prevalence of diabetes for different COVID-19 disease statuses. The error bars represent 95% CI. The figures on the bar are the number of studies for summarizing the pooled prevalence by meta-analysis. AF, Africa region; AM, Americas region; EMED, Eastern Mediterranean region; ER, Europe region; SEA: Southeast Asia region; WP, Western Pacific region.

Figure 2

Estimated PAF of diabetes on presence of severe disease (A) and COVID-19–related deaths (B) in countries from varied geographical regions. The bars denote the PAF in various countries, and the colors represent the various geographical regions. The dashed lines denote the average PAF.

Figure 3

Estimated PAF of diabetes on presence of severe disease and COVID-19–related deaths by subgroup. PAF shown by COVID-19 waves (A), WHO geographical regions (B), country income level (C), HAQ (D), diabetes background prevalence (E), undiagnosed diabetes proportion (F), IGT (G), and IFG (H). The color bars denote the PAF of diabetes on different worse outcomes of COVID-19 hospitalization. The error bars represent 95% CI. AF, Africa region; AM, Americas region; EMED, Eastern Mediterranean region; ER, Europe region; SEA: Southeast Asia region; WP, Western Pacific region.