Background: Several studies reported increased incidence of diabetes in individuals who recovered from coronavirus disease 2019 (COVID-19) caused by acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Objective: To determine risk, characteristics and potential mechanisms of new-onset diabetes in patients who recovered from COVID-19.

Methods: PubMed search up to May 26, 2022. Search terms are diabetes, hyperglycemia, SARS-CoV-2, COVID-19, cytokines, glucocorticoids. Cohort retrospective studies, pertinent in-vitro studies, pre-print and review articles are included.

Results: Large retrospective cohort studies have consistently shown increased risk of diabetes, mainly type 2, during a follow-up period of approximately 6-18 months after recovery from acute COVID-19. One cohort study also showed increased risk of diabetes (94% of cases were type 1 and type 2 diabetes) among pediatric population in the post COVID-19 period. Increased risk of incident diabetes occurred in non-hospitalized and hospitalized patients with COVID-19, with gradual incremental risk occurring in parallel to the severity of COVID-19. The largest cohort study has shown that older age, black race, higher body mass index (BMI), presence of cardiovascular disease, hypertension, and pre-diabetes further increased incident type 2 diabetes after COVID-19. Risk of new-onset diabetes after COVID-19 infection was greater than those following respiratory infections unrelated to COVID-19. Mechanisms of development of diabetes in the post-COVID-19 duration are unclear and likely multifactorial. Persistence of altered cytokines after apparent clinical cure of COVID-19 might worsen insulin resistance. In addition, direct invasion of pancreatic β-cells by SARS-CoV-2 could be among the underlying mechanisms.

Conclusions: New-onset type 2 diabetes may be one of the sequelae of COVID-19 infection. Physicians and patients should be aware about the possible occurrence of this complication for early diagnosis and treatment.