Spotlight on diabetes after COVID-19

Two recent studies indicated that patients who survive COVID-19 have an increased risk of developing diabetes.

The first study, published by The Lancet Diabetes & Endocrinology on March 21, used Veterans Affairs data to compare 181,280 patients with a positive COVID-19 test to more than 4 million contemporary controls and more than 4 million historical controls. At a median follow-up of 352 days, the COVID-19 group had an increased risk of diabetes (hazard ratio [HR], 1.40; 95% CI 1.3 to 1.44) and of being prescribed antihyperglycemic medication (HR, 1.85; 1.78 to 1.92) compared to the contemporary controls. The composite of those two outcomes occurred in 58.10 per 1,000 COVID-19 patients per year versus 40.07 per 1,000 contemporary controls. The risk of diabetes increased in a graded fashion with the severity of COVID-19 infection (outpatient, inpatient, ICU). The results were consistent in comparisons with the historical controls.

“Altogether, our results indicate that beyond the acute phase of COVID-19, survivors are at an increased risk of developing incident diabetes and antihyperglycaemic use; therefore diabetes should be considered as a component of the multifaceted long COVID. Post-acute care strategies of people with COVID-19 should also integrate screening and management of diabetes,” the authors said. They noted that the mechanisms for this association are undetermined and that the demographics of the study population (mostly White men) could limit the generalizability of the findings.

An accompanying editorial noted that another limitation of the study was the potential for differential rates of diabetes testing between COVID-19 cases and controls and speculated about possible explanations for the findings. “Among the most intriguing of hypotheses to explain the COVID-19 and diabetes connection is that SARS-CoV-2 virus might infect and replicate in the pancreas, injuring exocrine and endocrine cells,” the editorialists wrote. “Other potential mechanisms, which the authors mention, are also worthy of investigation, including autonomic dysfunction, immune response or induced autoimmunity, and low-grade inflammation,” the editorial noted.

The other study, published by Diabetologia on March 16, retrospectively analyzed a cohort of patients from 1,171 medical practices in Germany, including 35,865 patients with documented cases of COVID-19. They were propensity-score matched by demographics and comorbidities to an equal number of control patients who were treated for acute upper respiratory tract infections. During a median follow-up of 119 days and 161 days in COVID-19 and control patients, respectively, the COVID-19 group had increased type 2 diabetes incidence: 15.8 versus 12.3 per 1,000 person-years. The study authors calculated an incidence rate ratio for type 2 diabetes of 1.28 (95% CI, 1.05 to 1.57) associated with COVID-19. “If confirmed, the results of the present study indicate that diabetes screening in individuals who have recovered from even mild Covid-19 should be recommended,” the study authors said. They noted a number of uncertainties in this area of medicine, including whether pre-existing diabetes becomes apparent during COVID-19 and whether diabetes may be reversed after full recovery from COVID-19.