RESUMO
OBJECTIVE: To compare the effect of operation and observation on bone mineral mass in patients with mild asymptomatic hyperparathyroidism (HPT). DESIGN: A randomised 17-year follow-up study. SETTING: University hospital, Sweden. SUBJECTS: 48 women who had been diagnosed as having asymptomatic HPT during a health screening survey in Stockholm, Sweden during 1971-73. INTERVENTIONS: 26 patients were operated on and 22 were observed. 46 normocalcaemic women served as a reference population. 17 years later, operated on (n = 12), not operated on (n = 8) and control subjects (n = 16) were followed up. MAIN OUTCOME MEASURES: Bone mineral content (BMC) of distal non-dominant forearm, and serum concentrations of calcium and creatinine. RESULTS: On entering the study in 1971-73, the BMC of the distal forearm was 14% lower in the patients with HPT than in age, body mass, and postmenopausal age-matched controls (mean (SD) 1.01 (0.23) compared with 1.18 (0.30) g/cm; p < 0.05). During the first 3 years after operation bone mass increased significantly in the group operated on (n = 26) to 106% of the initial values (95% confidence interval (CI) 100% to 111%), remained unchanged (mean 101%; (97% to 106%)) in the unoperated group (n = 22), and decreased significantly to 94% (92% to 97%) of the initial values in the reference group (n = 46). At follow up 17 years later BMC of distal radius in the operated group (n = 12) and patients treated conservatively (n = 8) showed similar values; that were not significantly lower than those of the controls (difference: -12 (18)%). CONCLUSIONS: Our results suggest that patients with mild asymptomatic HPT have already experienced their major bone loss when diagnosed. Parathyroidectomy had an initial positive effect on bone mineralisation, but we could find no long-term advantage in operative treatments. During the 17 year follow-up period HPT patients who were not operated on showed an improvement in bone mass compared with healthy control subjects.