The estimated annual progression rate to diabetes in older adults with HbA1c-defined prediabetes was 5.3%.
New data suggest the estimated annual progression rate (APR) to diabetes in older adults with prediabetes identified by hemoglobin A1c (HbA1c) was 5.3% across various health care organizations.
This was noted to be different from previous US studies, which study investigators attributed to various differing study designs and populations.
Despite recommendations for using HbA1c to diagnose prediabetes, there are still uncertainties regarding the progression rate of HbA1c-defined prediabetes in clinical settings among US adults.
“Our findings may provide important information to evaluate the cost effectiveness of lifestyle interventions in older adults with prediabetes identified by HbA1c testing in clinical settings,” 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 from the Longitudinal Epidemiologic Assessment of Diabetes Risk (LEADR) study. The study consisted of data from 2,045,999 adults between January 2010 - December 2018 acros 10 geographically diverse US health care networks.
Prediabetes was defined as HbA1c level of 5.7% to 6.4% within 3 months of follow-up after HbA1c-based prediabetes diagnosis, and without kidney failure. The APR was estimated from mean 1-year cumulative incidence ([cases/patients]/ mean follow-up years) and 95% CIs were derived from Poisson regression models.
Then, estimates were stratified by baseline variables, including age group, sex, race and ethnicity, social vulnerability index (SVI), body mass index (BMI), HbA1c level, family history of diabetes, and hypertension diagnosis
A total of 50,152 patients were included in the study, with a median follow-up of 2.3 years. Data show the crude diabetes incidence was 53 per 1000 person-years (APR, 5.3%; 95% CI, 5.1% - 5.4%). The APRs were ≥5.0% for all groups except patients with the lowest SVI, BMI <30, or baseline HbA1c level of 5.7% to 5.9%.
They further found the most pronounced differences in progression were for BMI and HbA1c. For patients with BMI of 18.5 to 24.9, the APR was 3.5% (95% CI, 3.3% - 3.7%), when it was 7.6% (95% CI, 7.0% - 8.3%) among patients with a BMI of ≥40.
Moreover, patients with HbA1c levels of 5.7% to 5.9% had an APR of 2.8% (95% CI, 2.7% - 2.9%) compared with 8.2% (95% CI, 7.9% - 8.4%) among patients with HbA1c levels of 6.0% to 6.4%.
Investigators remarked the strengths of the study included the large sample of diverse patients, while limitations include patients’ unknown duration of prediabetes, possible incomplete capture of health care utilization, and the inability to distinguish between type 1 and type 2 diabetes.
“Owing to inherent selection bias, the EHR-based sample was representative of patients comprising the health care organizations contributing data and may not be representative of the general US population,” Koyama concluded.
The research letter, “Progression to Diabetes Among Older Adults with Hemoglobin A1c-Defined Prediabetes in the US,” was published in JAMA Network Open.