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Is Prediabetes in Older Adults a Risk Factor for Developing Type 2 Diabetes?

Sep 11, 2021
 
Editor: Steve Freed, R.PH., CDE

Author: Laura Martínez López, PharmD. Candidate 2021, Lake Erie College of Osteopathic Medicine, College of Pharmacy

Prediabetes has been linked as a risk factor to developing type 2 diabetes over the years, but limited data is available in the geriatric population.

Prediabetes prevalence is increasing, with estimates that 1 in 3 adults have prediabetes, and most do not know they have it. Having prediabetes can increase the risk of developing type 2 diabetes and cardiovascular diseases. Some risk factors include being overweight, being 45 years or older, having low physical activity, and having a family history of type 2 diabetes. Simple lifestyle modifications and physical activity can prevent type 2 diabetes progression. Some studies want to find risk factors in prediabetic adults that can lead to type 2 diabetes. However, this link is poorly understood in older adults.

 

In a recent study, clinicians compared the prevalence of diabetes based on HbA1c, Fasting Blood Glucose (FBG), or both. In addition, clinicians looked at the progression from normoglycemia to prediabetes, prediabetes to diabetes, or normoglycemia to diabetes in older adults from the Atherosclerosis Risk in Communities Study (ARIC). This cohort study took place in the late 1980s when participants were 45 to 64 years old. Over the years, participants were followed up, and visit five (2011 to 2013) was set as the baseline period for this study when they were 71 to 90 years of age. Then, patients were followed for an average of 5 more years until visit six between 2016 and 2017. Initially, 6,538 people participated in the ARIC study, but data from only 3,412 participants were used for this cohort. The definition of prediabetes used in this study was according to the ADA guidelines in which HbA1c levels are between 5.7% and 6.4%, and FBG is between 100mg/dL to 125mg/dL. The secondary analysis defined prediabetes as HbA1C levels of 6.0% to 6.4%, established by the International Expert Committee (IEC); and FBG of 110mg/dL to 126mg/dL, based on the World Health Organization (WHO). Incidentally, diabetes and diagnosed diabetes were defined as physician diagnoses where the HbA1c levels were 6.5% or higher, or FBG levels were at least 126 mg/dL.

In the cohort study, clinicians evaluated the incidence and incidence rates of total diabetes and diagnosed diabetes calculating person-years. In addition, they evaluated mortality during a mean follow-up of 5 years. Also, they conducted sensitivity and specificity analyses to account for the dropout because of death or nonparticipation. Additionally, they performed Cox proportional hazards regression to obtain hazard ratios (95% CIs).

During this cohort study, 3,412 participants without diabetes with a mean age of 75.6 years were followed up for a mean period of 5 years. At baseline (visit 5), 17% of participants were Black, and 60% were female. Prediabetes prevalence varied depending on the definition used. When using the ADA definition, prediabetes was present in 44% of participants based on HbA1c, 59% of participants based on impaired fasting glucose (IFG), and 29% of participants met both criteria. While using the IEC definition, the prediabetes prevalence was 15% based on HbA1c and 23% based on IFG. While looking at participants with HbA1c levels less than 5.7%, most of them were more likely to be Black or have FBG of 100-125 mg/dL.

Of those participants in visit 5, 61% went to visit 6, and 12% died before visit 6. Clinicians reported 156 incident total diabetes cases, 118 incident diagnosed diabetes cases, and 434 deaths. Using ADA definition for prediabetes using HbA1c, a total of 64% of participants with normoglycemia at visit five remained with normoglycemia, 17% progressed to prediabetes, 16% died, and 3% developed diabetes. From the prediabetes participants at baseline, 59% had no change in status, 19% died, 13% regressed to normoglycemia, and 9% progressed to diabetes. Using the ADA definition for prediabetes using FBG, 71% of participants with normoglycemia at the baseline had normal levels at visit 6, while 8% progressed to IFG, 19% died, and 3% developed diabetes. From those with prediabetes at baseline, 44% regressed to normoglycemia, 32% remained in the same category, 16% died, and 8% progressed to diabetes. Progression from prediabetes to diabetes was similar when grouping them by age (<75 years and ≥75 years) and by sex (men vs. women), but it was higher in Black older adults compared with White older adults using both HbA1c and IFB. The incidence rate using person-years for total diabetes was 118.9, while the incidence rate for diagnosed diabetes was 79.3.   

Overall, the prevalence of prediabetes was higher among older adults, but the progression was uncommon between the classifications due to the definitions used. These results indicated that prediabetes in older adults might not be a prediction for diabetes progression. The clinicians reported that the 2-hour glucose tolerance test was not conducted in the ARIC study, which is a limitation since no official diagnostic tool was used. Also, the sample size was limited to a certain age. These limitations can be taken into consideration for future studies.

Practice Pearls:

  • During this study, regression to normoglycemia or death with prediabetes were more common than progression to diabetes in the geriatric population.
  • During a six years follow-up, less than 12% of geriatric participants progressed from prediabetes to diabetes, regardless of its definition.
  • The various definitions and wide ranges in prevalence represent a challenge for understanding the burden of prediabetes in the geriatric population.

 

References:

Rooney, M. Risk of Progression to Diabetes Among Older Adults with Prediabetes. JAMA Intern Med (2021). doi:10.1001/jamainternmed.2020.8774.
https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2775594

 

Laura Martínez López, PharmD. Candidate 2021, Lake Erie College of Osteopathic Medicine, College of Pharmacy