New research explores rate of diabetes progression in older people with prediabetes

New data suggest that the estimated annual progression rate (APR) to diabetes in older adults with prediabetes identified by hemoglobin A1c (HbA1c) was 5.3% across various healthcare organizations.

This was noted to be different from previous US studies, which investigators attributed to various different study designs and populations.

Despite recommendations for using HbA1c to diagnose prediabetes, there are still uncertainties regarding the rate of progression of HbA1c-defined prediabetes in the clinical setting in US adults.

“Our results may provide important information to assess the cost-effectiveness of lifestyle interventions in older adults with prediabetes identified by HbA1c testing in a clinical setting,” wrote study author Alain K. Koyama, ScD, Division of Diabetes Translation, Centers for DIsease Control and Prevention.

Kohama and colleagues estimated the APR of HbA1c-defined prediabetes in adults ≥65 years of age from the Longitudinal Epidemiologic Assessment of Diabetes Risk (LEADR) study. The study consisted of data from 2,045,999 adults between January 2010 and December 2018 across 10 geographically diverse US healthcare networks.

Prediabetes was defined as an HbA1c level of 5.7% to 6.4% within 3 months of follow-up after diagnosis of prediabetes based on HbA1c, and without renal impairment. The APR was estimated from the mean cumulative incidence over 1 year ([cases/patients]/mean follow-up years) and 95% CIs were derived from Poisson regression models.

Next, the estimates were stratified by basic variables, including age group, sex, race and ethnicity, social vulnerability index (SVI), body mass index (BMI), HbA1c level, family history of diabetes and diagnosis of hypertension.

A total of 50,152 patients were included in the study, with a median follow-up of 2.3 years. The data show that the crude incidence of diabetes was 53 per 1000 person-years (APR, 5.3%; 95% CI, 5.1% – 5.4%). APRs were ≥ 5.0% for all groups except for patients with the lowest SVI, BMI

They further found that the most pronounced differences in progression were in BMI and HbA1c. For patients with a BMI of 18.5-24.9, the APR was 3.5% (95% CI, 3.3%-3.7%), while it was 7.6 % (95% CI, 7.0% – 8.3%) in patients with BMI ≥ 40.

Additionally, patients with HbA1c levels of 5.7% to 5.9% had a PCR of 2.8% (95% CI, 2.7% – 2.9%) versus 8.2% (95% CI, 7.9% – 8.4%) in patients with HbA1c levels of 6.0% – 6.4%.

Investigators noted that strengths of the study included the large sample of diverse patients, while limitations include the unknown duration of patients’ prediabetes, possible incomplete capture of healthcare utilization, and disability. distinguish between type 1 and type 2 diabetes.

“Due to an inherent selection bias, the EHR-based sample was representative of patients comprising the healthcare organizations providing data and may not be representative of the general U.S. population,” concluded Koyama.

The research letter, “Progression to diabetes in older adults with hemoglobin A1c-defined prediabetes in the United States,” was published in JAMA Network Open.