Diabetes Linked to Increased Mortality in Patients With COVID-19

A review of 24 meta-analyses supported the need for additional monitoring of patients with diabetes and COVID-19, especially if they have comorbidities associated with diabetes.

Patients with diabetes and its associated comorbidities need additional monitoring if they contract COVID-19, compared with patients without diabetes, to reduce deaths, according to a review published in Health Sciences Review.

Researchers conducted a review that included data from 24 relevant meta-analyses published by April 2021, with all studies including mortality as an outcome. The review adhered to guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement.

Of the 24 meta-analyses included, 9 indicated a link between diabetes and the mortality of patients who had COVID-19, while 15 reported a link between diabetes and other underlying health conditions in COVID-19–related patient mortality. Pooled odds ratios (ORs) and relative risk (RR) revealed a notable association between diabetes alone or its related comorbidities and the deaths of patients with COVID-19.

One notable meta-analysis, conducted by Shang et al, included 28 studies, finding that individuals with diabetes faced a significantly higher risk of mortality from COVID-19 (pooled OR, 2.21; 95% CI, 1.83-2.66; P < .001). This analysis also detected a moderate level of heterogeneity among the studies, as indicated by an I2 statistic of 50%.

Additional studies confirmed the link between diabetes and mortality from COVID-19.

Aggarwal et al analyzed 4 studies, but the results supported the association (OR, 2.03; 95% CI, 1.29-3.20) without any observed heterogeneity among the included studies. Varikasuvu et al included 47 studies and found an OR of 2.52 (95% CI, 1.93-3.30; P < .00001), emphasizing the elevated risk posed by diabetes. Mantovani et al analyzed 15 studies and determined a pooled OR of 2.68 (95% CI, 2.09-3.44), also indicating a greater likelihood of in-hospital mortality for patients with COVID-19 and diabetes. This analysis exhibited some heterogeneity, with an I2 of 46.7%.

Kumar et al investigated the severity and mortality of patients with COVID-19 and diabetes and found a significant association. The pooled OR for severity was 2.75 (95% CI, 2.09-3.62; P < .01), and for mortality, 1.90 (95% CI, 1.37-2.64; P < .01). These findings strongly support the connection between diabetes and adverse outcomes in patients with COVID-19. Similarly, Wu et al found a significant association, reporting a pooled OR of 1.75 (95% CI, 1.31-2.36; P = .0002).

Three studies in the review focused on RR. Guo et al reported a pooled RR of 2.96 (95% CI, 2.31-3.79; P < .001)—revealing an association of diabetes not only with disease severity but also with the risk of death in patients with COVID-19—and Hussain et al reported a pooled RR of 1.61 (95% CI, 1.16-2.25; P = .005). Although Huang et al reported a RR of 2.12 (95% CI, 1.44-3.11; P < .001), it is important to note that the I2 was 72%, indicating heterogeneity among the studies in the analysis.

Diabetes is commonly linked with various other medical conditions, including hypertension, obesity, hyperlipidemia, and others. Fifteen meta-analyses in this review shed light on the correlation between diabetes and adverse outcomes in individuals with COVID-19.

According to Tian et al, hypertension showed the highest mortality rate (56.8%), followed by diabetes (31.2%) and coronary heart disease or cardiovascular disease (21.5%). The pooled OR for patients with diabetes was 2.0 (95% CI, 1.7-2.3, P < .00001), indicating a significant association between diabetes and COVID-19–related mortality.

Nandy et al also reported a significant correlation, with an OR of 2.28 (95% CI, 1.40-5.55; P = .004), and Lu et al emphasized the increased mortality risk for patients with diabetes, with a pooled OR of 3.73 (95% CI, 2.35-5.90). Further, Qiu et al found that among patients with COVID-19, diabetes was associated with a 22.2% risk of complications.

Further studies consistently supported the significant correlation between diabetes and adverse outcomes, including mortality, severity, and complications in patients with COVID-19.

The authors concluded that increased age, male gender, dyspnea, diabetes, and hypertension are the most important risk factors for patients with diabetes and COVID-19. They have also reported congestive heart failure, hilar lymphadenopathy, bilateral lung involvement, and reticular patterns associated with severe disease. Overall, the RR of mortality in patients with diabetes and COVID-19 was found to be 1.59 (1.41-1.78), pointing to an increased mortality risk among patients with diabetes.

These findings underscore the importance of recognizing and closely monitoring the impact of diabetes in individuals with COVID-19.

“Diabetes and its associated comorbidities are significantly associated with the death of COVID-19 patients in all of the published meta-analyses,” the authors said. “Therefore, COVID-19 patients with diabetes and its associated comorbidities need much more monitoring to reduce deaths.”


Garg A, Kumar Posa M, Kumar A. Diabetes and deaths of COVID-19 patients: systematic review of meta-analyses. Health Sciences Review. Published online May 18, 2023. doi:10.1016/j.hsr.2023.100099

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