With self-referral, the average person experienced 696 days of visual acuity of 20/30 or worse in the better-seeing eye from DR, AMD, glaucoma, or URE between 2010 and their death. This number fell to 588 days with annual telemedicine screening, 574 days with biennial eye evaluation, and 572 days with annual eye evaluation. Self-referral offered the lowest costs and QALYs, followed by telemedicine, biennial evaluation, and annual evaluation ().
Costs, QALYs, and Cost-Effectiveness of Five Diabetic Retinopathy Screening and Treatment Alternatives Considering the Impacts of Diabetic Retinopathy Alone and the Impacts of Diabetic Retinopathy, AMD, Glaucoma, and URE
Self-referral resulted in average per person ophthalmologic-related costs of $7,368, of which 28% were paid by Medicare and 3% were productivity losses, with the remainder paid for by other insurers or out of pocket. Compared to self-referral, telemedicine increased costs by $3,343, biennial evaluation by $3,636, and annual evaluation by $4,809. Medicare paid 35% of the incremental costs of telemedicine, 24% of biennial evaluation, and 21% of annual evaluation.
Compared to self-referral, the ICER for annual telemedicine assessments was $55,000 per QALY gained, with an INB (assuming a WTP of $50,000 per QALY gained) of −$303 (); the ICER of biennial evaluation was $38,000 per QALY gained with an INB of $1,208; and the ICER of annual evaluation was $46,000 per QALY gained with an INB of $466. Biennial examination compared to annual telemedicine cost $8,107 per QALY gained with an INB of $1,511 assuming a WTP of $50,000 per QALY. Annual evaluation compared to biennial examination cost $136,170 per QALY gained with an INB of −$742.
Self-referral was most likely to be cost-effective at a WTP between $0 and $37,500 per QALY gained. Biennial evaluation was most likely to be cost-effective at a WTP between $37,500 and $150,000 per QALY gained, and annual evaluation was most likely to be cost-effective at WTP values greater than $150,000 per QALY gained ().
Probability Each Intervention is The Most Cost-effective Given a Range of Values for the Willingness to Pay per QALY Gained
The discounted lifetime EVPI was $78 per person. The cumulative EVPI over the study population of 9.1 million persons was $709 million.
Our model was most sensitive to the assumption that telemedicine could not detect URE. When we assumed that telemedicine could detect between 25% and 75% of URE (gamma distributed), telemedicine dominated biennial evaluation resulted in greater QALYs at lower cost, reversing our earlier result. In that scenario at a WTP of $50,000 per QALY, the INB of telemedicine compared to self-referral was $1,708, and the INB of biennial evaluation compared to telemedicine was −$500. When we assumed that telemedicine could detect 50% of URE, telemedicine was most likely to be cost-effective at a WTP between $33,000 and $400,000 per QALY gained. No treatment was most likely to be cost-effective at WTP values below $33,000 per QALY gained, and annual evaluation was most likely to be cost-effective at WTP values about $400,000 per QALY gained. We found that varying the discount rate from 0% to 5% only impacted the choice between biennial and annual evaluations and that annual evaluation was only more likely to be cost-effective at discount rates lower than our baseline.
No other parameter altered the rank order of scenario preferences. Compared to self-referral all scenarios were more cost-effective when the starting mean HbA1c and its rate of change were higher and less cost-effective when they were lower. The model was insensitive to univariate variations in the relative risk of death among people with diabetes, the screening compliance rate obtained by annual and biennial evaluations, variations in telemedicine costs, and the rate of impairment after progressing to vision-threatening disease. There was no plausible parameter value at which annual evaluation was cost-effective compared to biennial evaluation at a WTP value below $100,000 per QALY gained. At a WTP of between $100,000 and $130,000, annual evaluation was preferred to biennial evaluation when the discount rate was 0% and when one assumed faster disease progression rates.