Fifteen years of GH replacement improves body composition and cardiovascular risk factors

Abstract

Objective

Few studies have determined the effects of more than 5–10 years of GH replacement in adults on body composition and cardiovascular risk factors.

Design/patients

In this prospective, single-center, open-label study, the effects of 15 years of GH replacement on body composition and cardiovascular risk factors were determined in 156 hypopituitary adults (93 men) with adult-onset GH deficiency (GHD). Mean age was 50.5 (range 22–74) years at study start. Body composition was measured using dual-energy X-ray absorptiometry.

Results

The mean initial GH dose of 0.55 ( s.e.m. 0.03) mg/day was gradually lowered to 0.40 (0.01) mg/day after 15 years. The mean serum IGF1 SDS increased from −1.53 (0.10) at baseline to 0.74 (0.13) at study end ( P<0.001 vs baseline). Lean soft tissue (LST) increased to 3% above the baseline level at study end ( P<0.001). After a 9% decrease during the first year of treatment ( P<0.001 vs baseline), body fat (BF) started to increase and had returned to the baseline level after 15 years. Serum levels of total cholesterol and LDL-cholesterol decreased and serum HDL-cholesterol level increased. Fasting plasma glucose increased from 4.4 (0.1) at baseline to 4.8 (0.1) mmol/l at study end ( P<0.001). However, blood HbA1c decreased from 5.0 (0.1) to 4.6 (0.1) % ( P<0.001).

Conclusions

Fifteen-year GH replacement in GHD adults induced a transient decrease in BF and sustained improvements of LST and serum lipid profile. Fasting plasma glucose increased whereas blood HbA1c was reduced.