Cluster-randomized trials Covariate-constrained randomization Family caregiving Half-normal distribution Pragmatic trials Re-Randomization
Cluster-randomized trials (CRTs) are increasingly common in pragmatic trials of interventions for older adults, where staff of existing clinics or service agencies deliver interventions. The Adult Day Service (ADS) Plus intervention is delivered by trained staff at adult day service facilities to assist older adults with cognitive impairments and their family caregivers. Because sizable imbalances on important site characteristics might emerge from a simple randomization, we implemented a 3-stage constrained randomization approach to limit imbalance between intervention and usual care control conditions on 5 site characteristics: capacity; % of minority clients; % of clients with dementia; urban, rural or suburban location; and private or public ownership. In stage 1, the Balance Match Weighted (BMW) re-randomization procedure was used to assign 30 sites to ADS Plus or control arms based on the best randomization out of 20 total randomizations for minimizing site imbalance. In stage 2, propensity scores from the BMW logistic regression analysis for reserve sites were used to determine substitutions for randomized sites that opted out of the CRT prior to implementation. In stage 3, a minimization approach was used to add 20 more sites to the trial. A standardized metric based on the half-normal distribution of the absolute value of mean differences was used to assess site imbalance. After stage 3, the remaining imbalance for the 49 enrolled sites was reduced by 75% from what would have been expected from a simple randomization. Optimized randomization procedures with similar imbalance metrics should be used more routinely in pragmatic CRTs.
Application of randomization techniques for balancing site covariates in the adult day service plus pragmatic cluster-randomized trial
Creators
David L. Roth - Center on Aging and Health, Division of Geriatric Medicine and Gerontology, 2024 East Monument Street, Johns Hopkins University, Baltimore, MD, 21205, USA.
Jin Huang - Center on Aging and Health, Division of Geriatric Medicine and Gerontology, 2024 East Monument Street, Johns Hopkins University, Baltimore, MD, 21205, USA.
Laura N. Gitlin - Drexel University
Joseph E. Gaugler - University of Minnesota
Publication Details
Contemporary clinical trials communications, v 19, 100628
Publisher
Elsevier
Resource Type
Journal article
Language
English
Academic Unit
College of Nursing and Health Professions
Web of Science ID
WOS:000594377800009
Scopus ID
2-s2.0-85090047053
Other Identifier
991019169476104721
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