The parametric G-formula for time-to-event data: towards intuition with a worked example

Details

• Alternative Title:
  Epidemiology
• Personal Author:
  Keil, Alexander P. ; Edwards, Jessie K. ; Richardson, David R. ; Naimi, Ashley I. ; Cole, Stephen R.
• Description:
  Background
  
  The parametric g-formula can be used to estimate the effect of a policy, intervention, or treatment. Unlike standard regression approaches, the parametric g-formula can be used to adjust for time-varying confounders that are affected by prior exposures. To date, there are few published examples in which the method has been applied.
  
  Methods
  
  We provide a simple introduction to the parametric g-formula and illustrate its application in analysis of a small cohort study of bone marrow transplant patients in which the effect of treatment on mortality is subject to time-varying confounding.
  
  Results
  
  Standard regression adjustment yields a biased estimate of the effect of treatment on mortality relative to the estimate obtained by the g-formula.
  
  Conclusions
  
  The g-formula allows estimation of a relevant parameter for public health officials: the change in the hazard of mortality under a hypothetical intervention, such as reduction of exposure to a harmful agent or introduction of a beneficial new treatment. We present a simple approach to implement the parametric g-formula that is sufficiently general to allow easy adaptation to many settings of public health relevance.
  
  
• Subjects:
  Adult Algorithms Article Bone Marrow Transplantation Cause Of Death Confounding Factors (Epidemiology) Epidemiologic Methods Female Graft Vs Host Disease Humans Male Monte Carlo Method Multicenter Studies As Topic Probability

  More +
• Source:
  Epidemiology. 25(6):889-897.
• Pubmed ID:
  25140837
• Pubmed Central ID:
  PMC4310506
• Document Type:
  Journal Article
• Funding:
  R01 AI100654/AI/NIAID NIH HHS/United States ; R01 CA117841/CA/NCI NIH HHS/United States ; R01-AI100654/AI/NIAID NIH HHS/United States ; R01-CA117841/CA/NCI NIH HHS/United States ; T32 ES007018/ES/NIEHS NIH HHS/United States ; T42-OH008673-08/OH/NIOSH CDC HHS/United States
• Volume:
  25
• Issue:
  6
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:617f30526c90c8dad1c6c7508cc0cc6e1f5f763a98c965c4ea3cc9f8d77af6ca
• Download URL:
  https://stacks.cdc.gov/view/cdc/30268/cdc_30268_DS1.pdf
• File Type:
  [PDF - 708.24 KB ]