Alternative HbA1c cutoffs to identify high-risk adults for diabetes prevention: a cost-effectiveness perspective

Am J Prev Med. 2012 Apr;42(4):374-81. doi: 10.1016/j.amepre.2012.01.003.

Abstract

Background: 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.

Purpose: To assess the cost effectiveness associated with the alternative HbA1c cutoffs for identifying prediabetes.

Methods: 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.

Results: 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.

Conclusions: 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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Computer Simulation
  • Cost-Benefit Analysis
  • Diabetes Mellitus, Type 2 / prevention & control*
  • Glycated Hemoglobin A / analysis*
  • Health Surveys / statistics & numerical data
  • Humans
  • Markov Chains
  • Prediabetic State / diagnosis*
  • Prediabetic State / therapy
  • Preventive Health Services / economics
  • Preventive Health Services / methods*
  • Quality-Adjusted Life Years
  • Risk Factors
  • United States

Substances

  • Glycated Hemoglobin A