In a recent study published in the journal BMC Medicineresearchers estimated the prevalence of new-onset diabetes as a result of coronavirus disease 2019 (COVID-19).

Despite numerous vaccines and antiviral therapies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the COVID-19 pandemic continues to threaten public health and the economy, with over 634 million cases and counting 6.59 million dead to date. The presence of comorbid conditions can influence the clinical outcome of people with COVID-19.

Previous studies indicate that diabetes mellitus (DM) increases the risk of severe COVID-19, in-hospital death and acute respiratory distress syndrome. Notably, a meta-analysis concluded that new-onset diabetes is frequently observed in patients with COVID-19. Similarly, the incidence of newly diagnosed type 1 diabetes has increased in children after COVID-19.

Study: Risk of newly diagnosed diabetes after COVID-19: A systematic review and meta-analysis.  Image Credit: Proxima Studio/ShutterstockStudy: Risk of newly diagnosed diabetes after COVID-19: A systematic review and meta-analysis. Image Credit: Proxima Studio/Shutterstock

About the study

In the present study, the researchers systematically reviewed and meta-analyzed the literature to assess the prevalence of new-onset diabetes in patients with COVID-19. The Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Embase and PubMed databases were systematically searched for studies with a combination of terms related to SARS-CoV-2/COVID-19 and diabetes without language and time restrictions of publication / year.

Retrospective or prospective cohort studies were eligible for inclusion if 1) primary exposure was COVID-19, defined according to International Classification of Disease codes, 2) reported new-onset diabetes, and 3) determined relative associations between patients hospitalized and control population. Clinical cases/series, comments, letters and reviews have not been taken into consideration.

The primary outcome of interest in the study was the incidence of new-onset diabetes after SARS-CoV-2 infection and the risk of developing diabetes compared with controls. Subgroup analyzes were performed based on gender, age, type of diabetes, and time of onset, among others. In addition, the authors conducted two post hoc subgroup analyzes involving mild to moderate and severe COVID-19 patients.

A standardized spreadsheet was used to extract data on study design, participant characteristics, definitions of COVID-19 and DM, covariates, and length of follow-up (in person-years). The risk of bias was determined using the Newcastle-Ottawa scale. The incidence of new-onset diabetes was calculated from the reported number of cases with newly diagnosed diabetes and person-years of follow-up.

Diabetes rates among COVID-19 patients and controls were reported as relative risks along with their 95% confidence intervals. The I2 statistic and Cochran’s Q test assessed heterogeneity between studies.


The search criteria yielded 7746 articles. After screening, 7543 studies were excluded. Nine studies were included after all rounds of screening, including full-text reviews. Six studies were conducted in the United States (USA), two in England and one in Germany. Seven studies included adults only, one included adolescents only, and one had no age limit.

In select studies, there were more than four million COVID-19 patients and >34 million controls. The risk of bias was relatively low in selected studies. The mean follow-up time ranged between 64 and 352 days across studies. Overall, the incidence of new-onset DM per 1,000 person-years of follow-up was 15.53 cases. The relative risk of post-COVID-19 DM was 1.62 compared with controls.

The relative risk of developing type 1 DM was 1.48 and 1.7 for type 2 DM. The annual incidence of diabetes per 1,000 person-years was 3.65 in those younger than 18 years, 15, 53 in individuals between the ages of 18 and 65 and 17.45 among those over the age of 65. There was a statistically significant association between COVID-19 and the risk of developing DM across all age groups.

The incidence rate of new-onset diabetes was 3.14 and 3 in males and females, respectively, per 1,000 person-years. The incidence of new-onset diabetes was 2.96% in patients with mild to moderate COVID-19, with a 1.48-fold elevated risk compared to controls. In patients with severe COVID-19, the incidence of new-onset diabetes was 11.65%, with an increased risk of more than 1.67-fold.


In summary, the researchers estimated the incidence of new-onset diabetes to be 15.53 per 1,000 person-years. The relative risk of diabetes was 1.62 among COVID-19 patients compared with controls. Subgroup analyzes indicated that the risk of developing diabetes increased in patients with COVID-19 regardless of gender, age, type of diabetes, severity of COVID-19, and duration of follow-up.

However, the authors did not find a significant risk of developing unspecified diabetes. Furthermore, the results did not differ when unmeasured confounders were taken into account. These findings warrant continued attention to new-onset diabetes after SARS-CoV-2 infection, especially in the first three months post-COVID-19.

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