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A general method for calculating power for GEE analysis of complete and incomplete stepped wedge cluster randomized trials.

Publication ,  Journal Article
Zhang, Y; Preisser, JS; Turner, EL; Rathouz, PJ; Toles, M; Li, F
Published in: Stat Methods Med Res
January 2023

Stepped wedge designs have uni-directional crossovers at randomly assigned time points (steps) where clusters switch from control to intervention condition. Incomplete stepped wedge designs are increasingly used in cluster randomized trials of health care interventions and have periods without data collection due to logistical, resource and patient-centered considerations. The development of sample size formulae for stepped wedge trials has primarily focused on complete designs and continuous responses. Addressing this gap, a general, fast, non-simulation based power procedure is proposed for generalized estimating equations analysis of complete and incomplete stepped wedge designs and its predicted power is compared to simulated power for binary and continuous responses. An extensive set of simulations for six and twelve clusters is based upon the Connect-Home trial with an incomplete stepped wedge design. Results show that empirical test size is well controlled using a t-test with bias-corrected sandwich variance estimator for as few as six clusters. Analytical power agrees well with a simulated power in scenarios with twelve clusters. For six clusters, analytical power is similar to simulated power with estimation using the correctly specified model-based variance estimator. To explore the impact of study design choice on power, the proposed fast GEE power method is applied to the Connect-Home trial design, four alternative incomplete stepped wedge designs and one complete design.

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Published In

Stat Methods Med Res

DOI

EISSN

1477-0334

Publication Date

January 2023

Volume

32

Issue

1

Start / End Page

71 / 87

Location

England

Related Subject Headings

  • Statistics & Probability
  • Sample Size
  • Research Design
  • Randomized Controlled Trials as Topic
  • Humans
  • Cluster Analysis
  • Bias
  • 4905 Statistics
  • 4202 Epidemiology
  • 1117 Public Health and Health Services
 

Citation

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Zhang, Y., Preisser, J. S., Turner, E. L., Rathouz, P. J., Toles, M., & Li, F. (2023). A general method for calculating power for GEE analysis of complete and incomplete stepped wedge cluster randomized trials. Stat Methods Med Res, 32(1), 71–87. https://doi.org/10.1177/09622802221129861
Zhang, Ying, John S. Preisser, Elizabeth L. Turner, Paul J. Rathouz, Mark Toles, and Fan Li. “A general method for calculating power for GEE analysis of complete and incomplete stepped wedge cluster randomized trials.Stat Methods Med Res 32, no. 1 (January 2023): 71–87. https://doi.org/10.1177/09622802221129861.
Zhang Y, Preisser JS, Turner EL, Rathouz PJ, Toles M, Li F. A general method for calculating power for GEE analysis of complete and incomplete stepped wedge cluster randomized trials. Stat Methods Med Res. 2023 Jan;32(1):71–87.
Zhang, Ying, et al. “A general method for calculating power for GEE analysis of complete and incomplete stepped wedge cluster randomized trials.Stat Methods Med Res, vol. 32, no. 1, Jan. 2023, pp. 71–87. Pubmed, doi:10.1177/09622802221129861.
Zhang Y, Preisser JS, Turner EL, Rathouz PJ, Toles M, Li F. A general method for calculating power for GEE analysis of complete and incomplete stepped wedge cluster randomized trials. Stat Methods Med Res. 2023 Jan;32(1):71–87.
Journal cover image

Published In

Stat Methods Med Res

DOI

EISSN

1477-0334

Publication Date

January 2023

Volume

32

Issue

1

Start / End Page

71 / 87

Location

England

Related Subject Headings

  • Statistics & Probability
  • Sample Size
  • Research Design
  • Randomized Controlled Trials as Topic
  • Humans
  • Cluster Analysis
  • Bias
  • 4905 Statistics
  • 4202 Epidemiology
  • 1117 Public Health and Health Services