CAN PATIENT DECISION AIDS IMPROVE ADHERENCE AND BE COST EFFECTIVE? THE CASE OF OBSTRUCTIVE SLEEP APNEA

Purpose: Through improving the congruence between patient values and treatment choices, patient decision aids (PtDAs) have the potential to increase rates of adherence in many preference-sensitive decisions. This study explores whether the potential cost savings and health improvement associated with improved adherence would justify implementing a PtDA in patients with obstructive sleep apnea (OSA).

Method: We developed a decision analytic model which predicts the costs and benefits of treatment based on the effects on quality of life, motor vehicle crashes, and cardiovascular disease. In patients with moderate OSA, continuous positive airway pressure (CPAP) is generally more effective than oral appliances (OA), but is poorly tolerated by patients resulting in lower rates of adherence. The comparator arm followed current practice where the majority of patients receive CPAP. The intervention arm considered implementing a PtDA, with patients receiving the option they prefer. This assumes more patients will receive OA and that rates of adherence to both CPAP and OA will increase. Parameters for the proportion of patients preferring treatment and baseline rates of adherence were taken from the literature. The primary outcome was the incremental cost-effectiveness ratio (ICER) in terms of costs per quality-adjusted life year (QALY) gained 5 years after treatment. Uncertainty was addressed using a probabilistic analysis, and expected value of partial perfect information (EVPPI) calculated to determine future research design.

Result: At baseline the intervention arm had lower per patient costs and QALY ($5,507, 3.439) than the control arm ($6,178, 3.460). As expected, reducing non-adherence (from 0%-50%) in the intervention arm was associated with both lower costs ($54) and higher QALY scores (0.020). Conservative estimates suggest a PtDA would have to reduce non-adherence by 21% in order to be cost-effective at a $50,000/QALY threshold. EVPPI analysis suggested the rates of adherence to chosen treatment were the most important uncertain parameters, and with values over US $5 million, a clinical trial of the PtDA is justified.

Conclusion: Little consideration is currently given to the cost-effectiveness of implementing PtDAs in clinical practice. The preliminary results of this analysis suggest that a PtDAs could be cost-effective if they can improve treatment adherence. Our results are being used to inform the design a randomized clinical trial of a PtDA in patients with obstructive sleep apnea.