The effect of conjugated estrogens/bazedoxifene therapy on body weight of postmenopausal women: pooled analysis of five randomized, placebo-controlled trials

Objective:This post hoc analysis compared body weight, body mass index (BMI), and BMI category changes in postmenopausal women treated with conjugated estrogens/bazedoxifene (CE/BZA) versus placebo in the Selective Estrogens, Menopause, and Response to Therapy (SMART) trials.Methods:Data were pooled from five randomized, double-blind, placebo- and active-controlled studies in postmenopausal women aged 40 to 75 years with a uterus given CE 0.45mg/BZA 20mg (n=1,607), CE 0.625mg/BZA 20mg (n=1,598), or placebo (n=1,256) for at least 12 weeks and up to 2 years. Changes from baseline in body weight, BMI (kg/m(2)), and World Health Organization BMI category (underweight <18.5; normal 18.5 to <25; overweight 25 to <30; obese 30) during treatment were evaluated.Results:Mean body weight increased less than 0.9kg and mean BMI increased less than 0.4kg/m(2) in all treatment groups at all time points. There were no statistically significant between-group differences, except for significantly greater increases in weight (P=0.015) and BMI (P=0.014) with placebo versus CE 0.625mg/BZA 20mg at month 12. Approximately, 10% of women in the CE/BZA groups and 11% in the placebo group had increases in body weight greater than 7% of baseline. The majority of BMI changes were within 7%, and there were no statistically significant between-group differences in BMI category distributions during treatment.Conclusions:Significant increases in body weight or BMI were not observed in postmenopausal women receiving CE 0.45mg/BZA 20mg or CE 0.625mg/BZA 20mg for up to 2 years in the Selective Estrogens, Menopause, and Response to Therapy trials.