Abstract WP394: Insights Into The Cost-effectiveness Of Blood Pressure Management For Secondary Stroke Prevention

Abstract

Objective: To determine the relationship between the risk of dementia, risk of recurrent stroke and other factors on the cost-effectiveness of intensive blood pressure management for secondary stroke prevention. Methods: A Markov model incorporated data from the PROGRESS trial. It included cost (2011$) and utility estimates from the literature. Intensive management was a 9mmHg reduction in systolic blood pressure compared to usual management. The cost of the additional medications was assumed to be the cost of perindopril. Relative risk terms modified the probability of adverse events with intensive treatment. Outcomes were recurrent stroke, dementia, recurrent stroke with dementia and death. Quality of life with intensive management was lower than usual treatment. Assumptions were tested with one-way and multi-way sensitivity analyses. Results: For the base case analysis, the lifetime costs of usual management were $80,200 with 5.626 quality adjusted life years (QALYs). The lifetime costs of intensive management were $85,500 with 5.627 QALYs. The incremental cost-effectiveness ratio (ICER) was $5 million, thus the added costs of intensive management were not offset by increased quality of life. However, this conclusion was sensitive to several assumptions. Intensive management became cost-effective (ICER < $100,000) when (1) ages < 52 years were treated (base case: 64 years), (2) the quality of life with intensive management increased slightly, by 0.01, (3) the cost of BP medications was $270/year, (4) the probability of recurrent stroke was ≥ 5.4% (base case: 3.7%), or (5) the relative risk of recurrent stroke with intensive management was ≤ 0.69 (base case: 0.77). The probability of dementia or the relative risk of dementia did not influence the model. If the cost of medications to lower BP by 9 mmHg was ≤ $260/year, intensive management was dominant with lower lifetime costs and greater QALYs. Conclusion: With the base case assumptions, intensive BP management was not the cost-effective choice. Nevertheless cost-effective management can be achieved depending on the age of the cohort and the cost of maintenance medications. This analysis highlights important factors to be considered during the planned cost-effectiveness analysis of the SPS3 trial.