Statistical power considerations in genotype-based recall randomized controlled trials
Naeimeh Atabaki-Pasdar1, Mattias Ohlsson2, Dmitry Shungin1
1Department of Clinical Sciences, Genetic and Molecular Epidemiology Unit, Lund University, Malmö, SE-205 02, Sweden.
Abstract:
Randomized controlled trials (RCT) are often underpowered for validating gene-treatment interactions. Using published data from the Diabetes Prevention Program (DPP), we examined power in conventional and genotype-based recall (GBR) trials. We calculated sample size and statistical power for gene-metformin interactions (vs. placebo) using incidence rates, gene-drug interaction effect estimates and allele frequencies reported in the DPP for the rs8065082 SLC47A1 variant, a metformin transported encoding locus. We then calculated statistical power for interactions between genetic risk scores (GRS), metformin treatment and intensive lifestyle intervention (ILI) given a range of sampling frames, clinical trial sample sizes, interaction effect estimates, and allele frequencies; outcomes were type 2 diabetes incidence (time-to-event) and change in small LDL particles (continuous outcome). Thereafter, we compared two recruitment frameworks: GBR (participants recruited from the extremes of a GRS distribution) and conventional sampling (participants recruited without explicit emphasis on genetic characteristics). We further examined the influence of outcome measurement error on statistical power. Under most simulated scenarios, GBR trials have substantially higher power to observe gene-drug and gene-lifestyle interactions than same-sized conventional RCTs. GBR trials are becoming popular for validation of gene-treatment interactions; our analyses illustrate the strengths and weaknesses of this design.
Insights
Genotype-based recall (GBR) trials offer greater statistical power for detecting gene-treatment interactions compared to conventional randomized controlled trials (RCTs). This study highlights GBR
Area of Science:
- Pharmacogenomics
- Clinical Trial Design
- Biostatistics
Background:
- Randomized controlled trials (RCTs) frequently lack the statistical power to validate gene-treatment interactions.
- The Diabetes Prevention Program (DPP) provides valuable data for examining trial power.
- Gene-treatment interactions are crucial for personalized medicine and drug efficacy.
Purpose of the Study:
- To compare the statistical power of genotype-based recall (GBR) and conventional randomized controlled trials (RCTs) for validating gene-treatment interactions.
- To assess the impact of different sampling frames and outcome measurement errors on trial power.
- To evaluate the strengths and weaknesses of GBR designs in gene-treatment interaction studies.
Main Methods:
- Utilized published data from the Diabetes Prevention Program (DPP).
- Calculated sample size and statistical power for gene-metformin interactions using specific genetic variants (rs8065082 SLC47A1).
- Simulated power for interactions involving genetic risk scores (GRS), metformin, and intensive lifestyle intervention (ILI) under various scenarios, including GBR and conventional sampling.
Main Results:
- Genotype-based recall (GBR) trials demonstrated substantially higher statistical power than conventional RCTs of equivalent size for detecting gene-drug and gene-lifestyle interactions.
- The study quantified power for both time-to-event (type 2 diabetes incidence) and continuous (small LDL particle change) outcomes.
- GBR designs showed significant advantages across most simulated scenarios.
Conclusions:
- Genotype-based recall (GBR) designs offer a more powerful approach for validating gene-treatment interactions compared to traditional RCTs.
- GBR trials are a valuable tool for personalized medicine research, but their specific strengths and limitations require careful consideration.
- The findings underscore the potential of GBR for enhancing the efficiency of genetic research in clinical trials.
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