Alternative HbA1c cutoffs to identify high-risk adults for diabetes prevention: A cost-effectiveness perspective
New recommendations about the use of hemoglobin A1c (HbA1c) for diagnosing diabetes have stimulated a debate about the optimal HbA1c cutoff to identify prediabetes for preventive intervention.
To assess the cost effectiveness associated with the alternative HbA1c cutoffs for identifying prediabetes.
A Markov simulation model was used to examine the cost effectiveness associated with a progressive 0.1% decrease in the HbA1c cutoff from 6.4% to 5.5%. The target population was the U.S. nondiabetic population aged ?18 years. The simulation sample was created using the data of nondiabetic American adults from the National Health and Nutritional Examination Survey (NHANES 1999–2006). People identified as having prediabetes were assumed to receive a preventive intervention, with effectiveness the same as that in the Diabetes Prevention Program study under a high-cost intervention (HCI) scenario and in the Promoting a Lifestyle of Activity and Nutrition for Working to Alter the Risk of Diabetes study under a low-cost intervention (LCI) scenario. The analysis was conducted for a lifetime horizon from a healthcare system perspective.
Lowering the HbA1c cutoff would increase the health benefits of the preventive interventions at higher costs. For the HCI, lowering the HbA1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $27,000 and $34,000 per QALY gained, respectively. Continuing to decrease the cutoff from 5.8% to 5.7%, from 5.7% to 5.6%, and from 5.6% to 5.5% would cost $45,000, $58,000, and $96,000 per QALY gained, respectively. For the LCI, lowering the HbA1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $24,000 and $27,000 per QALY gained, respectively. Continuing to lower the cutoff from 5.8% to 5.7%, 5.7% to 5.6%, and 5.6% to 5.5% would cost $34,000, $43,000 and $70,000 per QALY gained, respectively.
Lowering the HbA1c cutoff for prediabetes leads to less cost-effective preventive interventions. Assuming a conventional $50,000/QALY cost-effectiveness benchmark, the HbA1c cutoffs of 5.7% and higher were found to be cost effective. Lowering the cutoff from 5.7% to 5.6% also may be cost effective, however, if the costs of preventive interventions were to be lowered.