Hormone Therapy for the Prevention of Chronic Conditions in Postmenopausal Persons—Reply.

An important aspect of risk-of-bias assessment is that risk of bias can vary by outcome. This explains why we rated outcomes from some ancillary studies of the WHI as low risk of bias, as Anderson notes. Comment & Response B In Reply b Regarding our systematic review on hormone therapy for the primary prevention of chronic conditions in postmenopausal persons,[1] Dr Anderson and Dr Chlebowski and Mr Aragaki express concern about our assessment of the methodological quality of the WHI, which we rated as fair quality or moderate risk of bias.[[2]] Bias, in general terms, is a systematic error in study design, conduct, or analysis that can overestimate or underestimate the true intervention effect.[4] However, quantifying bias and assessing the extent of the impact of bias on study results are usually impossible. [Extracted from the article]