Cost-Utility Analysis of Screening Strategies for Diabetic Retinopathy in Korea

Abstract

This study involved a cost-utility analysis of early diagnosis and treatment of diabetic retinopathy depending on the screening strategy used. The four screening strategies evaluated were no screening, opportunistic examination, systematic fundus photography, and systematic examination by an ophthalmologists. Each strategy was evaluated in 10,000 adults aged 40 yr with newly diagnosed diabetes mellitus (hypothetical cohort). The cost of each strategy was estimated in the perspective of both payer and health care system. The utility was estimated using quality-adjusted life years (QALY). Incremental Cost Effectiveness Ratio (ICER) for the different screening strategies was analyzed. After exclusion of the weakly dominating opportunistic strategy, the ICER of systematic photography was 57,716,867 and that of systematic examination by ophthalmologists was 419,989,046 from the perspective of the healthcare system. According to the results, the systematic strategy is preferable to the opportunistic strategy from the perspective of both a payer and a healthcare system. Although systematic examination by ophthalmologists may have higher utility than systematic photography, it is associated with higher cost. The systematic photography is the best strategy in terms of cost-utility. However systematic examination by ophthalmologists can also be a suitable policy alternative, if the incremental cost is socially acceptable.

Keywords: Cost-utility Analysis; Diabetic Retinopathy; Markov Model; Quality-Adjusted Life Years (QALY).

Fig. 1. Markov model of no screening group. A decision node (□) is the decision to test a contact by using the respective screening procedure. Branches from a change node (○) represent the possible outcomes of an event; terminal nodes (◃) are assigned the cost of a prior series of actions and events. Probabilities (p): see model specifications; #: complementary probability (all probabilities of chance node's branches to sum to 1.0). pNR, probability of no retinopathy; pNPDR, probability of NPDR; pPDR, probability of PDR; pCSME, probability of CSME; pNPDRobs, probability of remained NPDR; pNPDRtoPDR, probability of NPDR to PDR; pNPDRtoCSME, probability of NPDR to CSME; pPDRnolaserSVL, probability of PDR to SVL after no laser therapy; pCSMEnolaserSVL, probability of CSME to SVL after no laser therapy.

Fig. 2. Markov model of opportunistic examination group. pOeNE, probability of not examined in opportunistic examination group; pPDRlaserSVL, probability of PDR to SVL after laser therapy; pCSMElaserSVL, probability of CSME to SVL after laser therapy; pSpNR, probability of no retinopathy in systematic photography group; pSpNPR, probability of negative predictive ratio in systematic photography group; pSpPPR, probability of positive predictive ratio in systematic photography group.

Fig. 3. Markov model of systematic photography group.

Fig. 4. Markov model of systematic examination by ophthalmologists.