Miriam E Tucker
May 24, 2017
HbA1c may be the most effective method to identify patients with undiagnosed prediabetes and diabetes, and point-of-care testing further enhances that screening ability in primary-care settings, new research suggests.
The findings were published recently in the Annals of Family Medicine by Heather P Whitley, PharmD, of Auburn University Harrison School of Pharmacy, Montgomery, Alabama, and colleagues.
"First, diabetes and prediabetes need to be on our radar as possible diagnoses. In the United States, where we have such a heavy prevalence of diabetes, we need to be thoughtful and aggressive in screening," Dr Whitley told Medscape Medical News.
And, for screening purposes, the data suggest that HbA1c is a better test than is a fasting blood glucose because postmeal glucose spikes happen sooner in the course of developing type 2 diabetes than does a high fasting.
"Probably if we're using A1cs we're catching more," she noted.
And, not surprisingly, use of a point-of-care HbA1c machine enabled detection of prediabetes and diabetes cases in a timelier manner compared with use of an outside lab.
"I think it's important to make sure the test is done. Regarding the machine, look at your patient population and decide if it's worth it or not," advised Dr Whitley, who has published a previous article comparing the features of three currently available point-of-care HbA1c tests, one of which is a handheld device and the other two of which are bench-top models (Diabetes Spectr. 2015;28:201-208).
Screening Method Improves Outcome
The latest study was done in a single family-medicine clinic from April 2013 through March 2014. A total of 689 patients seen on Tuesdays were evaluated for eligibility, and 164 who met the American Diabetes Association's screening age cutoff of 45 years (and older) and were without exclusion criteria were screened using a point-of-care HbA1c test.
Another 709 patients seen on Wednesdays underwent usual clinic care, and after exclusions 324 were evaluated by chart review.
Most of the patients (87%) were white, 55% were female, mean age was 63 years, and mean body-mass index was 31.0 kg/m2.
In the active screening arm [HbA1c point-of-care test], just 37% of the patients had an HbA1c of 5.6% or below (normoglycemia). Over half (53%) met the HbA1c criteria for prediabetes (5.7%–6.4%), while 10% were in the diabetes range (≥6.5%).
In the standard-practice arm, 22% (73) of the 324 evaluated persons were tested, most often by blood glucose (96%, typically as part of a larger venipuncture chemistry panel and not always fasting). Only four individuals received HbA1c testing, and one got both.
Of these, 33% (24) were in the prediabetes range and 8% (six) tested in the diabetes range, while the majority (59%) tested euglycemic (n=43).
The association between screening outcome and screening method was statistically significant in favor of HbA1c (P = .005).
In a post hoc analysis, Dr Whitley and colleagues reanalyzed their data using the screening criteria of the United States Preventative Services Task Force (USPSTF) for overweight or obese patients aged 40 to 70 years.
Those recommendations reduced the number of people screened from 164 [using ADA criteria] to 104 and missed identifying 36 patients with prediabetes and six with diabetes HbA1c levels.
Nonetheless, "Regardless of guidelines used, the analysis shows that systematically screening patients is more effective than standard screening practices," Dr Whitley and colleagues write.
And as for point-of-care testing, she told Medscape Medical News, "you get the results in a few minutes; then you can implement something to improve that care during that visit."
This project was funded by the Diabetes Hands Foundation through the Big Blue Test. The authors report no further relevant financial relationships.