Gonadal status is an important determinant of bone density in acromegaly.

Abstract

To measure bone mineral density (BMD) in patients with acromegaly and to look for clinical features which may explain previously reported discrepant results. Prospective case controlled observational study. 18 patients with acromegaly (seven women, 11 men; mean age 53.2 +/- 3.5 years). Eight patients had active disease and 10 had controlled acromegaly. Growth hormone and insulin-like growth factor-1 (IGF-1) concentrations were measured to assess disease activity. BMD was measured at four sites on the lumbar spine, three at the femoral neck and at Ward's triangle using a Hologic dexa scanner. Results were compared to a locally determined control population (n = 1800). In eight patients with active acromegaly, urinary free pyridinoline and deoxypyridinoline, and serum osteocalcin, propeptide of type 1 procollagen, vitamin D, 1000 h parathyroid hormone, bone specific alkaline phosphatase, calcium and phosphate concentrations were measured before and after 6 months treatment with octreotide. The mean BMD for all acromegalic patients was not significantly different from the control population except at the femoral neck where it was increased (P = 0.05). At all sites, the BMD of patients who had been hypogonadal (n = 12/18) was significantly lower (P < 0.05-0.01) than that of patients who had been eugonadal (n = 6/18). BMD for hypogonadal patients was lower than the control population at Ward's triangle (P = 0.03). Eugonadal acromegalic patients had BMD greater than non-acromegalic controls at all sites. Patients with controlled acromegaly had a higher BMD than non-acromegalic controls, but there were no differences in BMD between patients with active and controlled acromegaly. Serum IGF-1 concentrations decreased from 64.5 +/- 5.1 nmol/l to 37.5 +/- 6.9 nmol/l (P = 0.02) after 6 months treatment with octreotide, but there was no change in any of the biochemical markers of bone turnover. Eugonadal acromegalic patients have increased lumbar spine and femoral neck BMD compared to hypogonodal acromegalic patients and the general population, but it is reduced if patients have been hypogonadal.