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Table 1 5 different methods of analysis to estimate the association between treatment and outcome

From: Instrumental variable analysis to estimate treatment effects: a simulation study showing potential benefits of conditioning on hospital

 

Analysis strategy

Formula

a

Univariable regression analysis

logit(P[Yā€‰+ā€‰1])ā€‰=ā€‰Ī²0ā€‰+ā€‰Tā€‰āˆ—ā€‰Ī²T

b

Regression analysis with covariate adjustment

logit(P[Yā€‰+ā€‰1])ā€‰=ā€‰Cā€‰āˆ—ā€‰Ī²Cā€‰+ā€‰Tā€‰āˆ—ā€‰Ī²T

c

Propensity score adjustment

PSā€‰=ā€‰Cā€‰āˆ—ā€‰Ī²C

logit(P[Yā€‰+ā€‰1])ā€‰=ā€‰PSā€‰āˆ—ā€‰Ī²PSā€‰+ā€‰Tā€‰āˆ—ā€‰Ī²T

d

IV analysis

logit(P[Yā€‰+ā€‰1])ā€‰=ā€‰Zā€‰āˆ—ā€‰Ī²Z

e

IV analysis with correction for hospital

logit(P[Yā€‰+ā€‰1])ā€‰=ā€‰Zā€‰āˆ—ā€‰Ī²Zā€‰+ā€‰Hā€‰āˆ—ā€‰Ī²H

f

IV analysis with correction for hospital and all measured and unmeasured confounders

logit(P[Yā€‰+ā€‰1])ā€‰=ā€‰Zā€‰āˆ—ā€‰Ī²Zā€‰+ā€‰Hā€‰āˆ—ā€‰Ī²Hā€‰+ā€‰Cā€‰āˆ—ā€‰Ī²Cā€‰+ā€‰Uā€‰āˆ—ā€‰Ī²U

  1. Z: treatment preference as instrument: proportion of treated patients within each hospital
  2. H: hospital
  3. C: patient characteristics
  4. PS: propensity score
  5. T: treatment
  6. Ī²0: intercept