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Table 5 Hazard ratio estimates from the Rotterdam tumor bank dataset

From: On hazard ratio estimators by proportional hazards models in matched-pair cohort studies

Model Analysis set Target HR HR estimate 95% CI
Stratified Cox modela Matched cohort Conditionale 1.47 1.18 1.83
Unstratified Cox modelb Matched cohort Marginale 1.33 1.13 1.57
IPW Cox modelc Original cohort Marginalf 1.32 1.07 1.62
Multivariable Cox modeld Original cohort Conditionalf 1.48 1.27 1.71
IPW multivariable Cox modelc,d Original cohort Conditionalf 1.58 1.28 1.96
Unadjusted Cox model Original cohort Biased 0.84 0.75 0.95
  1. CI confidence interval, IPW inverse-probability weighted, HR hazard ratio
  2. aStratified on matched pairs
  3. bUsing a robust variance estimator aggregating residuals within pairs
  4. cUsing a robust variance estimator aggregating residuals within an individual woman
  5. dAdjusted for age at surgery, menopausal status, tumor size, tumor grade, progesterone receptors, oestrogen receptors, and exp(–0.12 * the number of positive lymph nodes). Age and the transformed number of nodes were included by linear and quadratic terms
  6. eTarget population is the matched part of unexposed population (treated with chemotherapy)
  7. fTarget population is total (unexposed and exposed) population