Incidence of diabetes after infection with COVID-19
Incidence of diabetes after infection with COVID-19

Incidence of diabetes after infection with COVID-19

In a recent study published in the latest issue of Diabetologyresearchers investigated the incidence of diabetes among cases of coronavirus disease 2019 (COVID-19).

Examination: Incidence of newly diagnosed diabetes after Covid-19. Image credit: Gecko Studio / Shutterstock


There is scientific evidence of impaired glucose-stimulated insulin secretion following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. It most likely occurs because SARS-CoV-2 damages pancreatic β cells by triggering proinflammatory cytokines. Proinflammatory pathways cause low-quality inflammation in adipose tissue, a key player in the pathogenesis of type 2 diabetes. Subsequently, emerging hyperglycaemia and insulin resistance occurred in patients who had recovered from COVID-19.

However, it is still unknown whether these metabolic changes are short-lived or may increase the risk of persistent diabetes in those recovering from COVID-19.

About the study

In the current retrospective cohort study, researchers screened 8.8 million patients from Disease Analyzer (DA), a health database that records a panel of 1171 physician practices in Germany. Patients with acute upper respiratory tract infections (AURI) constituted the control group for the study. The mean age of control group participants was 43 years and 46% were women.

The research team used the code International Classification of Diseases (ICD) -10 for disease identification during the study. Therefore, the ICD-10 codes U07.1 and J00 – J06 designated cases of newly diagnosed COVID-19 and AURI, respectively. The two study cohorts included individuals with newly diagnosed COVID-19 or AURI with index dates for the first diagnosis between March 1, 2020 and January 31, 2021. However, all type 2 diabetes cases and other types of diabetes or unspecified diabetes diagnosed after the index dates, was categorized under ICD-10 codes E11 and E12-E14.

Follow-up continued until July 2021 during the study, with a median of 119 days for COVID-19 and 161 days for AURI patients.

The researchers performed 1: 1 propensity score matching for age, gender, health insurance, comorbidities, and index month for COVID-19. They obtained incidence ratios (IRRs) for emerging diabetes using the person method using the Poisson regression models that take into account varying exposure times via offsets.

Survey results

There were 35,865 COVID-19 infected individuals during the study period and an equal number of AURI individuals after matching propensity scores. The clinical and demographic characteristics of the 35,865 AURI controls were similar to the COVID-19 group.

Overall, the study population included a healthier sample with milder COVID-19, which required fewer admissions (~ 10%) and no history of diabetes. Women accounted for 52% of the 2.4 million people with COVID-19 in Germany during the study period January 2020 to February 2021.

The number of hospital visits one year after index dates was comparable in COVID-19 and AURI groups. Likewise, the documented hospitalization cases were the same in COVID-19 and AURI cohorts during the follow-up period.

Regarding medications prescribed to the individuals in both groups, non-steroidal antirheumatics were often prescribed on index dates. But later, while COVID-19 patients were more likely to be prescribed povidone iodine because of its antiviral properties against SARS-CoV-2, AURI patients were prescribed antibiotics. Furthermore, more than 50% of the subjects in both the COVID-19 and AURI groups were not prescribed any glucose-lowering drugs when they were diagnosed with diabetes.

Kaplan-Meier curves for the COVID-19 group showed a significant increase in the incidence of type 2 diabetes, which continued throughout the study period; however, such differences for Kaplan-Meier curves were not observed for unspecified diabetes or other forms. The authors noted increased IRRs for type 2 diabetes, but not for other forms of diabetes and unspecified diabetes.

The IRRs for type 2 diabetes in the control and COVID-19 groups were 13.6 and 20.5 per 1000 people; subsequently, the total IRR was 1.51.

The first sensitivity analysis of type 2 diabetes gave an IRR of 1.26. For the second sensitivity analysis, the researchers selected control group participants who produced SARS-CoV-2 test reports seven days after the index date of AURI diagnosis, without having been diagnosed with ICD-10 code U07.1.


The results of the study revealed a temporal correlation between mild COVID-19 and newly diagnosed type 2 diabetes, which underlined active monitoring of glucose dysregulation after recovery from SARS-CoV-2 infection. These results are consistent with 29 occurrences per 1,000 people with emerging diabetes in 47,780 COVID-19 patients reported in a retrospective cohort study of hospitalized COVID-19 patients in the UK.

To conclude, the authors strongly recommended mandatory screening of individuals who have recovered from COVID-19 for early diagnosis of new-onset diabetes. In the future, studies examining the effects of COVID-19 on glucose and HbA1c measurements may help devise comprehensive treatment strategies for high-risk patients.

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