Cost Effectiveness Analysis of Riluzole for ALS in Ontario Home Care Setting

Abstract

Objective: To identify the factors associated with the prescription of riluzole and assess its cost-effectiveness for patients diagnosed with Amyotrophic Lateral Sclerosis (ALS) in long stay home care in Ontario, Canada.

Method: A retrospective cohort study was conducted using the Ontario Association of Community Care Access Centres – Home Care (OACCAC-HC) data. Assessment records of ALS patients admitted into home care between April 1st, 2005 and March 31st, 2013, who had information on whether or not they used riluzole, were reviewed. Univariate and multiple logistic regressions analysis were used to identify the predictors influencing the receipt of riluzole. Variables included in the analyses were chosen in correlation to the prognostic factors identified in the literature review. For the cost-effectiveness analysis, cost data were obtained from relevant literatures and published information on Canadian Institute for Health Information Patient Cost Estimator accounting for the cost of administration of riluzole, standard supportive home care services, and cost-savings from delay in hospitalization. Effectiveness was measured using time to discharge from home care due to death, placement into long-term care, and hospitalization, controlling for potential confounding variables using propensity score stratification. The incremental cost-effectiveness ratio was calculated based on time spent in different states and the associated utility scores using the stratified population and expressed as cost per life-year gained and quality-adjusted life-year gained. Sensitivity analyses included one-way deterministic sensitivity analysis to investigate the change in ICER due to variations in specific input parameters. Scenario analyses were developed to depict the ICERs in best and worst case scenarios.

Resuts: The total study population comprised of 1,351 patients diagnosed with ALS, of which 1,277 patients had information on the use of riluzole. In the multiple logistic regression analysis, older age, moderate – moderate severe impairment in cognitive functions, not being married and geographical locations across LHINs (Champlain, Erie St. Clair, Hamilton Niagara Haldimand Brant, Mississauga Halton, North East, South East, and South West) decreased the likelihood of riluzole prescription. Primary analysis showed that treatment with riluzole was associated with prolonged survival in home care [HR = 0.86; 95% confidence interval: 0.745 – 0.99; p=0.046]. Survival gain associated with riluzole was 1.5 months, while the incremental cost was approximately $5,000 per patient. Thus, the incremental cost-effectiveness ratio of riluzole versus standard supportive home care services was $41,128.85 per life-year gained or $55,579.53 per quality-adjusted life-year gained. One-way deterministic sensitivity analysis suggested an ICER ranging from $50,000 – 78,000 per QALY, while scenario analyses depicting best and worst case scenarios suggested an ICERs of $29,890.36 per QALY and $106,641.52 per QALY.

Conclusion: Patient characteristics such as age, cognitive score, geographical location and marital status markedly influenced drug utilization of riluzole. In addition, the findings of this study indicate that riluzole has a borderline or unfavorable cost-effectiveness for patients diagnosed with ALS in home care setting.