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Using conditional power of network meta-analysis (NMA) to inform the design of future clinical trials
Adriani Nikolakopoulou1, Dimitris Mavridis, Georgia Salanti
1Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, University Campus, Ioannina, 45110, Greece.
Abstract:
Clinical trials are typically designed with an aim to reach sufficient power to test a hypothesis about relative effectiveness of two or more interventions. Their role in informing evidence-based decision-making demands, however, that they are considered in the context of the existing evidence. Consequently, their planning can be informed by characteristics of relevant systematic reviews and meta-analyses. In the presence of multiple competing interventions the evidence base has the form of a network of trials, which provides information not only about the required sample size but also about the interventions that should be compared in a future trial. In this paper we present a methodology to evaluate the impact of new studies, their information size, the comparisons involved, and the anticipated heterogeneity on the conditional power (CP) of the updated network meta-analysis. The methods presented are an extension of the idea of CP initially suggested for a pairwise meta-analysis and we show how to estimate the required sample size using various combinations of direct and indirect evidence in future trials. We apply the methods to two previously published networks and we show that CP for a treatment comparison is dependent on the magnitude of heterogeneity and the ratio of direct to indirect information in existing and future trials for that comparison. Our methodology can help investigators calculate the required sample size under different assumptions about heterogeneity and make decisions about the number and design of future studies (set of treatments compared).
Insights
This study introduces a new method to calculate conditional power (CP) for network meta-analyses, optimizing clinical trial sample sizes and designs. It helps researchers determine the necessary information size and comparisons for future studies.
Area of Science:
- Biostatistics
- Clinical Epidemiology
- Health Research Methodology
Background:
- Clinical trials aim to test intervention effectiveness but require context from existing evidence.
- Network meta-analyses (NMA) integrate data from multiple trials with competing interventions.
- Planning future trials can be enhanced by understanding the existing evidence network.
Purpose of the Study:
- To present a methodology for evaluating the impact of new studies on the conditional power (CP) of updated network meta-analyses.
- To extend the concept of CP from pairwise meta-analysis to network meta-analysis.
- To provide a framework for estimating required sample sizes for future trials within a network.
Main Methods:
- Developed a methodology to assess how new studies, their information size, comparisons, and heterogeneity affect CP in NMA.
- Extended conditional power calculations from pairwise meta-analysis to network settings.
- Estimated required sample sizes using direct and indirect evidence for future trials.
Main Results:
- Conditional power for treatment comparisons in NMA is influenced by heterogeneity and the balance of direct/indirect evidence.
- The methodology was applied to two published networks, demonstrating its practical utility.
- New studies' characteristics significantly impact the CP of the updated network meta-analysis.
Conclusions:
- The proposed methodology aids investigators in calculating sample sizes under varying heterogeneity assumptions.
- It supports informed decision-making regarding the number and design of future studies in complex evidence networks.
- This approach enhances the efficiency and relevance of clinical trial planning within the context of existing evidence.
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