Thursday, July 3, 2025

Journal Club: Huybrechts & Henandez-Diaz: "Calling It a Targeted Trail Doesn't Make it One." [Simulating RCTs]

 Here's an interesting article from JAMA Psychiatry:

Estimating Treatment Effects From Observational Data—Calling It a Target Trial Does Not Make It One     Krista F. Huybrechts, MS, PhD1,2; Sonia Hernández-Díaz, MD, DrPH2

Find it here.  It might come with an access version here.

  • See also NEJM, Hubbard 2024, on "target trial emulation." - here.  
  • And, Hernan, the target trial framework, causal inference from observational data, Ann Intern Med 2025 here. (My blog re Hernan here.)
  • There's also Wilson, Real World Data - Trials to Practice, Lancet 2024 here.  
  • And Wang, Emulating RCTs with Databases, JAMA 2023, here.  
    • Wang has already been cited 241 times.  

Find an AI summary below.

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"Calling It a Target Trial Doesn’t Make It One" — Huybrechts & Hernández-Díaz (JAMA Psychiatry, 2025)

This editorial underscores that simply labeling an observational study as a "target trial emulation" does not ensure its rigor.  [Ha!]

The authors explain how true target trial emulation requires careful alignment of key elements: eligibility, treatment assignment, and the start of follow-up ("time zero")—just as in a randomized controlled trial (RCT).

They warn of immortal time bias, a design flaw common in real-world data studies, where periods in which outcomes cannot occur are improperly handled, leading to inflated treatment benefits. For instance, including prevalent users of a drug (rather than new users) can bias results, as only survivors remain in the sample. [patients who tolerate the drug, for example]

Target trial emulation is a valuable framework, but only when fully applied: researchers must explicitly define the hypothetical trial’s protocol and transparently map each component using real-world data. 

Otherwise, the label becomes a veneer over flawed methods. The takeaway: design trumps terminology, and emulation demands rigorous planning—not just a rhetorical nod to RCTs.