Estimating the Effect of a Treatment When There Is Nonadherence in a Trial

Details

• Personal Author:
  Dukes O ; Richardson DB ; Tchetgen Tchetgen EJ
• Description:
  Randomized trials offer a powerful strategy for estimating the effect of a treatment on an outcome. However, interpretation of trial results can be complicated when study subjects do not take the treatment to which they were assigned; this is referred to as nonadherence. Prior authors have described instrumental variable approaches to analyze trial data with nonadherence; under their approaches, the initial assignment to treatment is used as an instrument. However, their approaches require the assumption that initial assignment to treatment has no direct effect on the outcome except via the actual treatment received (i.e., the exclusion restriction), which may be implausible. We propose an approach to identification of a causal effect of treatment in a trial with 1-sided nonadherence without assuming exclusion restriction. The proposed approach leverages the study subjects initially assigned to control status as an unexposed reference population; we then employ a bespoke instrumental variable analysis, where the key assumption is "partial exchangeability" of the association between a covariate and an outcome in the treatment and control arms. We provide a formal description of the conditions for identification of causal effects, illustrate the method using simulations, and provide an empirical application. [Description provided by NIOSH]
• Subjects:
  Epidemiology Occupational Health Safety
• Keywords:
  Analytical Processes Author Keywords: Instrumental Variables Intervention Nonadherence Noncompliance Randomized Trials Statistical Quality Control Treatment
• ISSN:
  0002-9262
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; North Carolina ; OSHA Region 3 ; OSHA Region 4 ; OSHA Region 9 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  192
• Issue:
  10
• NIOSHTIC Number:
  nn:20069011
• Citation:
  Am J Epidemiol 2023 Oct; 192(10):1772-1780
• Contact Point Address:
  Dr. David Richardson, Department of Environmental and Occupational Health, Susan & Henry Samueli College of Health Sciences, University of California, Irvine, 653 E. Peltason Drive, Irvine, CA 92697
• Email:
  david.richardson@uci.edu
• Federal Fiscal Year:
  2024
• Performing Organization:
  University of North Carolina-Chapel Hill
• Peer Reviewed:
  True
• Start Date:
  20190801
• Source Full Name:
  American Journal of Epidemiology
• End Date:
  20220731
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:15fcc93ebe283af3e7b02797d1af11921532b0758040f945100499841ce2f23f2d955445f2faef369237e8f0d165f022be8cfb3c4f3f825bc7e3f29dbaa0b119
• Download URL:
  https://stacks.cdc.gov/view/cdc/207567/cdc_207567_DS1.pdf
• File Type:
  [PDF - 360.38 KB ]