In Reply: Dr Blackwell objects to the results of the WHI randomized trials of estrogen with and without progestin, which showed an increase in urinary incontinence with treatment, because of methodological issues. He suggests that an important limitation of the study is a lack of data on gynecologic conditions (endometriosis, fibroids, and interstitial cystitis). We disagree. First, these conditions are uncommon in postmenopausal women. Second, in a randomized controlled trial as large as the WHI, study groups are generally comparable with respect to all variables (measured and unmeasured). As shown in the baseline characteristics table of our article,1 chronic conditions were evenly distributed between treatment and control groups. This design enhances our ability to make inferences about the effect of the intervention on the outcome and is why the randomized trial remains the criterion standard for providing evidence on the effects of an intervention.
Estrogen, Progestin, and Urinary Incontinence—Reply. JAMA. 2005;294(21):2696-2698. doi:10.1001/jama.294.21.2697