TREATMENT OF POSTMENOPAUSAL OSTEOPOROSIS WITH A COMBINATION OF GROWTH-HORMONE AND PAMIDRONATE - A PLACEBO-CONTROLLED TRIAL

OBJECTIVE It is known that growth hormone can induce accelerated bone turnover in GH deficient people as well as healthy elderly people. In this study we examined the effect of recombinant human GH (rhGH) on bo ne mineral mass and bone turnover in the presence of the bone resorpti on inhibiting agent, pamidronate. Effects on body composition were als o studied. METHODS Twenty-one post-menopausal osteoporotic women were treated with the bisphosphonate pamidronate during 12 months. During t he initial 6 months rhGH (0.0675 IU/kg, 3 times/week) was administered in a placebo controlled fashion (10 vs 11 patients). MEASUREMENTS Bon e mineral content (BMC) of the lumbar spine and femoral neck was measu red with dual-energy X-ray absorptiometry and BMC of the distal and pr oximal forearm with single-photon absorptiometry. Body composition was measured with bioelectrical impedance and total body dual-energy X-ra y absorptiometry. Serum IGF-l and biochemical indices of bone turnover were also measured. RESULTS The group treated with rhGH showed a two to three-fold increase in serum IGF-l levels. No effects on bone miner al mass were observed in the group treated with rhGH, either after the initial 6 months of treatment with rhGH or after the total period of 12 months. in women treated with pamidronate, however, a consistent in crease of about 5% at the lumbar spine and somewhat less in the distal forearm was reached from 6 months onwards. In neither group was any c hange observed in BMC at the femoral neck or forearm. Compared to base line, the biochemical measurements of bone turnover showed a decrease of about 50% in the pamidronate treated group, but this effect was blu nted in the group additionally treated with rhGH. The body composition measurements showed clear effects of rhGH administration: a decrease in fat mass of about 5% and an increase in lean body mass of about 3%. However, these effects disappeared after the treatment with rhGH was stopped and both fat mass and lean body mass returned to initial value s. CONCLUSIONS The present study suggests that treatment with rhGH blu nted both the pamidronate induced accumulation of bone mineral mass an d the reduction of biochemical markers of bone turnover. Furthermore, the positive effect of rhGH on body composition disappears completely after cessation of treatment with rhGH.