Valuing benefits to inform a clinical trial in pharmacy : do differences in utility measures at baseline affect the effectiveness of the intervention?

Abstract

Background: The generic health-related quality-of-life (HR-QOL) utility measures the EQ-5D and SF-6D are both commonly used to inform healthcare policy developments. However, their application to pharmacy practice is limited and the optimal method to inform policy developments is unknown.

Objectives: Our objective was to test the sensitivity of the EQ-5D and SF-6D within pharmacy when measuring whether changes in health status or other co-variates at baseline affect the effectiveness of the intervention at follow-up. A further objective was to consider the implications of the findings for pharmacy research and policy.

Methods: The EQ-5D and SF-6D utility measures were employed within a randomized controlled trial (RCT) of community pharmacy-led medicines management for patients with coronary heart disease. The intervention covered a baseline visit with the potential for follow-up. Simultaneous quantile regression assessed the impact of the intervention on both EQ-5D and SF-6D measures at follow-up, controlling for baseline health, appropriateness of treatment, personal characteristics and self-reported satisfaction.

Results: No statistically significant difference in HR-QOL across the intervention and control groups at follow-up was reported for either measure. Increased health gain was however associated with the baseline utility score (with the EQ-5D more sensitive for those in worse health) and the appropriateness of treatment, but not patient characteristics or self-reported satisfaction.

Conclusion: Neither generic measure detected a gain in HR-QOL as a result of the introduction of an innovative pharmacy-based service. This finding supports other work in the area of pharmacy, where health gains have not changed following interventions. Disease-specific utility measures should be investigated as an alternative to generic approaches such as the EQ-5D and SF-6D. Given that the RCT found an increase in self-reported satisfaction, broader measures of benefit that value patient experiences, such as contingent valuation and discrete-choice experiments, should also be considered in pharmacy.