Datta SK (COE- Durham), Whited JD
(COE- Durham), Bursell SE
(Harvard Medical School)
To compare the effectiveness and cost of using teleophthalmology (TO) versus routine eye exam (EE) for diagnosing diabetic retinopathy and macular edema.
We conducted the analysis by developing a Markov model. A cohort of 50-year old diabetics entered the model in “good ocular health.” In following one-year cycles they remained in this health state, developed proliferative diabetic retinopathy (PDR) or clinically significant macular edema (CSME), or died. If they developed PDR or CSME, they may receive treatment and regain good ocular health, develop blindness, remain alive with PDR or CSME, or die. The intervention subtrees differed by 1) the proportion of diabetic patients screened by EE (0.60-0.83); 2) TO image failure rate (26%); 3) the test characteristics of TO and EE; and 4) adherence to follow-up exam (0.87 for TO and 0.77 for EE). We derived transition probabilities, intervention test characteristics, health state utilities, and annual cost of blindness from the literature. We derived intervention costs via micro-costing and treatment costs from Medicare reimbursement rates. We applied a 3% discount rate to future costs and effectiveness. We conducted 10,000 iterations of second-order Monte Carlo simulation of the Markov model to generate results. We also conducted extensive one-way sensitivity analysis to determine which parameters drove the model and the threshold values at which the results could change.
Preliminary model results estimated a lifetime expected cost of $620 (95% confidence interval (CI) $510-$732) for a patient receiving annual TO screening and $708 (95% CI $495-$968) for a patient receiving annual routine EE. TO patients accrued 9.0 QALYs (95% CI 8.6-9.4 QALYs) and routine EE patients also accrued 9.0 QALYs (95% CI 8.6-9.5). The model was sensitive to five model parameters: 1) EE time, 2) gradable image percentage, 3) proportion of population screened by EE and TO, 4) follow-up adherence rate, and 5) sensitivities of TO and EE.
Teleophthalmology is potentially comparable to routine eye exam for diagnosing PDR and CSME but may do so at lower cost per patient.
Teleophthalmology may provide a cost effective solution for improving compliance with VA guidelines that call for annual eye screening for diabetic veterans.