The effect of recombinant human GH replacement therapy on lipoprotein(a) and other lipid parameters in adults with acquired GH deficiency: results of a double-blind and placebo-controlled trial

The effect of GH substitution on serum lipids and lipoproteins, and in particular lipoprotein(a) (Lp(a)), was investigated in 32 adults with postoperative (acquired) GH deficiency as part of a double-blind, placebo-controlled trial. Seventeen men and fifteen women, aged 18-59 years (mean 42 years) from two centres (Hannover and Gottingen) were randomly assigned to two groups. Group P (placebo) received placebo for the first 12 months and recombinant human GH (rhGH) for the following 12 months (open phase). Group V (verum) was treated with rhGH for two consecutive periods of 12 months each. The target dose of rhGH was 2 U/m(2) per day, given subcutaneously daily at bedtime. Serum concentrations of Lp(a), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides were determined at 0, 12 and 24 months. In group V, Lp(a) increased significantly in the first as well as in the second year of treatment (P=0.02, 12 months versus baseline; P=0.016, 24 months versus 12 months), In contrast, Lp(a) levels remained unchanged in group P during the first 12 months (P=0.826 versus baseline), but increased significantly (P=0.002) during the second year, when all patients were administered GH. The increase in Lp(a) after 12 months of rhGH replacement therapy in all 32 patients was significant for Lp(a) baseline concentrations both above and below 20 mg/dl and was independent of the apolipoprotein(a) isoforms. Total and LDL-C decreased significantly after 1 year and triglycerides after 2 years in group V. A significant reduction was also observed in the TC/HDL-C and the LDL-C/HDL-C ratios, Our study shows an unfavorable effect of rhGH replacement therapy on Lp(a) levels, which is, however, counteracted by a favorable effect of rhGH on TC, LDL-C and the TC/LDL-C and LDL-C/HDL-C ratios.