Value of information methods for planning and analyzing clinical studies optimize decision making and research planning

OBJECTIVE: The results of two randomized clinical trials (RCTs) demonstrate the clinical effectiveness of alternatives to casting for certain ankle and wrist fractures. We illustrate the use of value of information (VOI) methods for evaluating the evidence provided by these studies with respect to decision making. STUDY DESIGN AND SETTING: Using cost-effectiveness data from these studies, the expected value of sample information (EVSI) of a future RCT can be determined. If the EVSI exceeds the cost of the future trial for any sample size, then the current evidence is considered insufficient for decision making and a future trial is considered worthwhile. If, on the other hand, there is no sample size for which the EVSI exceeds the cost, then the evidence is considered sufficient, and no future trial is required. RESULTS: We found that the evidence from the ankle study was insufficient to support the adoption of the removable device and determined the optimal sample size for a future trial. Conversely, the evidence from the wrist study was sufficient to support the adoption of the removable device. CONCLUSIONS: VOI methods provide a decision-analytic alternative to the standard hypothesis testing approach for assessing the evidence provided by cost-effectiveness studies and for determining sample sizes for RCTs.