Treatment of acromegaly has substantial effects on body composition. A long-term follow-up study.

BACKGROUND Acromegaly is associated with changes in body composition. Long-term changes following acromegaly treatment and the impact of different treatments have been less investigated. METHODS We performed a retrospective study in 201 patients with acromegaly. Body composition was assessed by dual-energy X-ray absorptiometry (DXA). To investigate specific effects of treatment vs ageing, changes in body composition were compared in a group of patients evaluated both at the time of active and controlled disease (A>C; n=31) and in another group of patients evaluated two times while the disease was controlled (C>C; n=32). RESULTS In the whole cohort, IGF-I correlated with fat (r=-0.369;p C and C>C groups were comparable for age, sex, BMI and follow-up duration (p=n.s.). Reduction in IGF-I levels was associated with an increase in fat mass and a decrease in lean mass in the A>C group, which was four and eight times more pronounced compared to the C>C group (fat mass: +39±34 vs +10±15%, p<0.001; lean mass: -8±8 vs -0.2±6%, p<0.001, respectively). Changes in fat mass were negatively associated with IGF-I (r=-0.450; p=0.011) and independent of the individual therapy. The daily dose of pegvisomant correlated with fat mass (r=0.421;p=0.002) and insulin sensitivity index (r=-0.466;p<0.001). CONCLUSIONS Treatment of acromegaly strongly impacts body composition until biochemical disease remission, characterized by an increase in fat mass and a decrease in lean mass. These changes are closely associated with the normalization of IGF-I. Thereafter, body composition changes are similar to what is observed with ageing.