Purpose: The American Diabetes Association (ADA) developed a questionnaire-based scoring system to screen for undiagnosed diabetes, wherein persons with a score of ≥10 are considered at high risk and recommended for further screening. We assessed the cost-effectiveness of the recommended cutoff score of 10 and other alternative cut-points of the scoring system.
Method: We used a validated simulation model to estimate the lifetime cost-effectiveness associated with a 1 point increment in risk score from 5 to 15. We used data from the National Health and Nutritional Examination Survey (2007) to estimate the prevalence and characteristics of the undiagnosed diabetes population, and sensitivities and specificities of each alternative cutoff. Persons who screened positive were assumed to receive a follow-up diagnostic test and intensive glycemic management if confirmed to have diabetes. Outcomes were measured by expected life-years, quality-adjusted life-years (QALYs), and medical costs. Incremental Cost-Effectiveness Ratio (ICER) of one cutpoint was measured by the incremental cost per QALY gained comparing with its next higher cutpoint. The analysis was conducted from a societal perspective.
Results: The proportion of undiagnosed diabetes detected, health benefit, cost and ICER by alterative cutoff score are presented in the table. A lower cutpoint resulted in a larger proportion of the undiagnosed diabetes detected and greater health benefits, but also in higher medical costs and higher ICER. The cutpoints in the range of 11 to 15 have ICERs lower than $50,000 and the cutpoint of 10 was associated with an ICER of $55,000/QALY.
Cutpoint | Undiagnosed Diabetes Cases Detected,% | Life-year Gained† | QALY Gained† | Incremental Cost | Cost per QALY |
5 | 77.8 | 0.009 | 0.008 | 1,420 | 176,000 |
6 | 70.5 | 0.010 | 0.012 | 1,088 | 94,000 |
7 | 64.6 | 0.012 | 0.013 | 911 | 72,000 |
8 | 64.3 | 0.015 | 0.014 | 809 | 60,000 |
9 | 57.1 | 0.016 | 0.013 | 794 | 59,000 |
10 | 31.4 | 0.017 | 0.014 | 787 | 55,000 |
11 | 21.1 | 0.018 | 0.016 | 760 | 48,000 |
12 | 29.7 | 0.018 | 0.016 | 718 | 44,000 |
13 | 18.8 | 0.021 | 0.016 | 677 | 43,000 |
14 | 7.3 | 0.029 | 0.015 | 620 | 42,000 |
15 | 1.1 | - * | - | - |
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Conclusions: There was a tradeoff between the total health benefit and economic efficiency by lowering the cutoff score. If $50,000/QALY were used as the acceptable willingness-to-pay threshold, a cutoff score of ≥11 should be selected.