A review including nearly 40 million total participants showed a statistically significant positive association between infection with COVID-19 and risk of type 1 or type 2 diabetes.
Following SARS-CoV-2 infection, individuals of all ages and genders had a higher incidence and relative risk (RR) of being diagnosed with either type 1 diabetes (T1D) or type 2 diabetes (T2D), according to a review published in BMC Medicine.
According to the authors, this suggests clinicians should pay particular attention to patients in the first 3 months after COVID-19 for new-onset T1D or T2D.
To come to these findings, the authors conducted a systematic review and meta-analysis of 9 studies including nearly 40 million total participants and nearly 200,000 cases of diabetes reported. All studies were published by June 10, 2022.
They found the overall incidence of diabetes after COVID-19 was 15.53 cases per 1000 person-years (95% CI, 7.91-25.64).
The overall RR of diabetes following COVID-19 infection was elevated (RR, 1.62; 95% CI, 1.45-1.80). The RR of T1D specifically was 1.48 (95% CI, 1.26-1.75) and of T2D was 1.70 (95% CI, 1.32-2.19) compared with patients who did not have COVID-19.
For patients who had COVID-19 and an unspecified type of diabetes, RR was 1.50 (95% CI, 0.87-2.58).
RR was fairly consistent across all age groups, being 1.72 (1.19-2.49) for patients younger than 18 years, 1.63 (1.26-2.11) for patients 18 and older, and 1.68 (1.22-2.30) for patients older than 65.
RR was about 2 for each gender group. Male patients had an RR of 2.08 (1.27-3.40) and female patients had an RR of 1.99 (1.47-2.80).
Additionally, the risk of diabetes was highest in the first 3 months following SARS-CoV-2 infection (RR, 1.95; 1.85-2.06), and patients with severe COVID-19 were at higher risk (RR, 1.67; 1.25-2.23) of diabetes after infection.
The authors noted these results remained significant even after accounting for the possibility of unmeasured confounding factors.
They also wrote that similar results have been reported in patients with other viral infections, with an increased incidence of diabetes compared with patients not infected.
“Our subgroup analysis revealed a 1.2-fold increased risk of developing diabetes after COVID-19 compared to patients with other upper respiratory tract infections and a 1.82-fold increased risk of developing diabetes after COVID-19 compared to the general population,” the authors said. “This reinforces the need for clinicians to pay attention to patients’ glucose metabolism in the post-acute phase of COVID-19.”
While this is reported to be the largest and most wide-ranging analysis on diabetes incidence among patients with COVID-19 currently, there are multiple limitations worth noting.
First, all included studies used a retrospective design and used large electronic health care databases to construct cohorts and define health characteristics based on validated definitions, suggesting that a chance of misclassification bias cannot be ruled out. Second, some studies used contemporary controls, meaning there is a chance some patients in the control groups had SARS-CoV-2 infection but did not test for it. Third, the studies were conducted in various countries and in different regions within the same country. Finally, the study designs were heterogeneous.
“As the number of available prospective cohort studies on this topic remains small, more high-quality studies are needed to confirm our results,” the authors said.
Zhang T, Mei Q, Zhang Z, et al. Risk for newly diagnosed diabetes after COVID-19: a systematic review and meta-analysis. BMC Med. Published online November 15, 2022. doi:10.1186/s12916-022-02656-y