Objective: Only two medications, estrogen and injectable salmon calcitonin, are currently approved by the FDA for the treatment of osteoporosis. Oral etidronate has been investigated but not approved for osteoporosis therapy. We compared the three available anti-resorptive medications in untreated osteoporotic women.
Design: A nonrandomized, open label trial. After baseline biochemistry and bone mineral density (BMD) determinations, subjects self-selected therapy based on descriptions of the three drugs which were similar for all patients. Bone densitometry of the lumbar spine, femoral neck and distal and proximal forearm sites was repeated every 6 months.
Results: Twenty-one patients chose estrogen, 20 chose etidronate and 11 chose calcitonin. Fear of breast cancer was the most common reason given for not choosing estrogen therapy. Mean age was slightly lower and spine and hip bone densities slightly higher in the estrogen group compared with both the etidronate and calcitonin groups. In the lumbar spine, all three agents resulted in similar small increments (mean increments 1.2-4.4% at 2 years). In the estrogen group, there was no change in femoral neck density while there were significant losses in both calcitonin and etidronate groups (3.1-4.9%). In the forearm, there was either no change (distal site) or an increment (proximal site) in the estrogen group, while both etidronate and calcitonin groups demonstrated a mean loss at both sites over the 2-year observation period.
Conclusions: These preliminary results suggest that all three agents appear equally effective at maintaining or increasing BMD of the lumbar spine, while estrogen appeared more effective at maintaining or increasing BMD of the appendicular skeleton. This study underscores the need for an alternative to estrogen therapy which is equally effective and can be given orally for those in whom estrogen is either contraindicated or undesirable.