Weight gain on androgen deprivation therapy: which patients are at highest risk?

OBJECTIVE To identify factors associated with weight gain at 1 year from initiation of androgen deprivation therapy (ADT). METHODS A retrospective review assessed weight change among 118 men with nonmetastatic prostate cancer treated with ADT for at least 6 months. Outcome associations were tested using 2-tailed t tests and linear regression. RESULTS Men in our cohort had significant weight gain (+1.32 kg, P=.0005) in the 1 year after ADT initiation. Three risk factors for weight gain on ADT were identified as follows: age<65 years (2.72 kg gained, P=.001), body mass index (BMI)<30 (1.98 kg gained, P=.00002), and nondiabetic status (1.56 kg gained, P=.0003). Multivariable regression found both age<65 years (beta=4.01, P=.02) and BMI<30 (beta=3.57, P=.03) to be independently predictive of weight gain, whereas nondiabetic status was nonsignificantly predictive of weight gain (beta=2.14, P=.29). Weight change was further stratified by the total number of risk factors present (risk score): scores of 0, 1, 2, and 3 risk factors corresponded to weight changes of -1.10, +0.41, +1.34, and +3.79 kg, respectively (P-trend=.0005). CONCLUSION Age<65 years and BMI<30 were both independently associated with weight gain 1 year after starting ADT. Increasing weight gain was also strongly associated with increasing number of baseline risk factors present. Despite traditional concerns about ADT in unhealthy men, these data suggest younger, healthier patients may be at higher risk for gaining weight on ADT and should be counseled accordingly.