Individualized Net Benefit estimation and meta-analysis using generalized pairwise comparisons in N-of-1 trials

Background: The Net Benefit (delta) is a measure of the benefit-risk balance in clinical trials, based on generalized pairwise comparisons (GPC) using several prioritized outcomes and thresholds of clinical relevance. We extended delta to N-of-1 trials, with a focus on patient-level and population-level delta.Methods: We developed a delta estimator at the individual level as an extension of the stratum-specific delta, and at the population-level as an extension of the stratified delta. We performed a simulation study mimicking PROFIL, a series of 38 N-of-1 trials testing sildenafil in Raynaud's phenomenon, to assess the power for such an analysis with realistic data. We then reanalyzed PROFIL using GPC. This reanalysis was finally interpreted in the context of the main analysis of PROFIL which used Bayesian individual probabilities of efficacy.Results: Simulations under the null showed good size of the test for both individual and population levels. The test lacked power when being simulated from the true PROFIL data, even when increasing the number of repetitions up to 140 days per patient. PROFIL individual-level estimated delta were well correlated with the probabilities of efficacy from the Bayesian analysis while showing similarly wide confidence intervals. Population-level estimated delta was not significantly different from zero, consistently with the previous Bayesian analysis.Conclusion: GPC can be used to estimate individual delta which can then be aggregated in a meta-analytic way in N-of-1 trials. GPC ability to easily incorporate patient preferences allow for more personalized treatment evaluation, while needing much less computing time than Bayesian modeling.