THE COST-EFFECTIVENESS OF AN RCT TO ESTABLISH WHETHER 5 OR 10 YEARS OF BISPHOSPHONATE TREATMENT IS THE BETTER DURATION FOR WOMEN WITH A PRIOR FRACTURE

Purpose: Five years of bisphosphonate treatment have proven efficacy in reducing fractures. Concerns exist that long-term bisphosphonate treatment may actually result in an increased number of fractures. This study evaluates, in the context of England and Wales, whether it is cost-effective to conduct a randomised controlled trial (RCT) and what sample size may be optimal, to estimate the efficacy of bisphosphonates in fracture prevention beyond 5 years.

Methodology: An osteoporosis model was constructed to evaluate the cost-effectiveness of extending bisphosphonate treatment from 5 years to 10 years. Two scenarios were run. The first using long-term efficacy data from published literature, and the second using distributions elicited from clinical experts. Results of a proposed RCT were simulated. Expected value of sample information techniques were applied to calculate the expected net benefit gained from conducting such an RCT at varying levels of participants per arm and to compare this with proposed trial costs.

Results: Without further information, the better duration of bisphosphonate treatment was estimated to be 5 years using the published data from the literature, but 10 years using the elicited expert opinions, although in both cases uncertainty was substantial. Results from both scenarios showed that conducting a RCT with up to 50,000 women per arm was cost-effective. High net benefit returns were consistently associated with 5,000 participants per arm.

Conclusions : An RCT to evaluate the long-term efficacy of bisphosphonates in fracture prevention appears to be cost-effective for informing decision making in England and Wales.