HbA1c-based screening of general population reduced time to diabetes diagnosis
In a British database, 1% of participants ages 40 to 70 years had undiagnosed diabetes. Researchers estimated that population-based screening using HbA1c level could have reduced the time to diagnosis in this group by a median of 2.2 years.
Screening middle-aged patients using HbA1c level may reduce the time to diabetes diagnosis by more than two years, a recent study estimated.
Researchers looked at 166,846 UK Biobank participants ages 40 to 70 years who had their HbA1c level measured at enrollment (but not provided to participants or clinicians), had linked longitudinal primary care data, and had no pre-existing diabetes diagnosis. Patients were considered to have diabetes if they had an enrollment HbA1c level of 6.5% or greater. For this group, researchers assessed the time between enrollment HbA1c level measurement and subsequent clinical diabetes diagnosis up to 10 years and looked at clinical factors associated with delayed diabetes diagnosis. Results were published Nov. 22 by Diabetologia.
A total of 1,703 (1.0%) of participants without a diabetes diagnosis had undiagnosed diabetes based on calibrated HbA1c levels at study enrollment, with a median HbA1c level of 6.8% (interquartile range [IQR], 6.6% to 7.4%). These participants represented an additional 13.0% (95% CI, 12.4% to 13.6%) of diabetes cases in the study population relative to the 13,077 participants with a pre-existing diagnosis. The median time to clinical diagnosis for those with undiagnosed diabetes was 2.2 years, with a median HbA1c level at clinical diagnosis of 7.5% (IQR, 6.8% to 9.5%. Male sex and body mass index (BMI) of 30 kg/m2 or greater were associated with shorter time to diabetes diagnosis (hazard ratios, 1.12 [95% CI, 1.00 to 1.25] and 1.25 [95% CI, 1.12 to 1.39], respectively). Female participants with lower HbA1c and BMI measurements at enrollment experienced the longest delay to clinical diagnosis.
UK Biobank participants are not a representative cohort of the United Kingdom, as they are more predominantly White, are from less deprived areas, and have better health outcomes compared with the general population, the study authors noted. Research participants may have also had more frequent health care appointments, potentially leading to earlier diabetes diagnosis; therefore, the resulting reduction in time to diagnosis may be an underestimate of the true effect, they noted.
“Unless diabetes risk scores are improved (especially in the low BMI group), population-based screening with HbA1c is the only way to reliably identify undiagnosed diabetes,” the authors wrote. “However, the cost-effectiveness of this approach merits further assessment and will vary based on the degree of HbA1c testing in the underlying population.”