Summary
We performed a 2-year extension of our previous 2-year randomized controlled trial of the effects of hydrochlorothiazide on
bone mineral density. The improvements in bone density seen in the first 2 years were sustained throughout the extension study.
Thiazides provide a further option in the prevention of postmenopausal bone loss.
Introduction
Thiazide diuretics reduce urinary calcium excretion and therefore might prevent osteoporosis. Previously we reported a 2-year
randomized controlled trial of hydrochlorothiazide treatment in 185 postmenopausal women that showed positive benefits of
hydrochlorothiazide on bone density. Here, we report the results of a 2-year extension to that study.
Methods
Of 185 healthy postmenopausal women, 122 agreed to continue in a double-blinded 2-year extension taking 50 mg hydrochlorothiazide
or placebo daily. Measurements of bone density occurred every 6 months and of calcium metabolism at 2 and 4 years.
Results
The improvements in bone density seen in the first 2 years of the trial were sustained throughout the extension. There were
significant between-groups differences in the change in bone density over 4 years at the total body (0.9%, P < 0.001), legs (1.0%, P = 0.002), mid-forearm (1.1%, P = 0.03), and ultradistal forearm (1.4%, P = 0.04). At the lumbar spine (0.9%, P = 0.76) and femoral neck (0.4%, P = 0.53) the between-groups differences did not reach statistical significance.
Conclusions
Hydrochlorothiazide produces small positive benefits on cortical bone density that are sustained for at least the first 4 years
of treatment. They provide a further option in the prevention of postmenopausal bone loss, especially for women with hypertension
or a history of kidney stones.
Keywords Bone density - Diuretic - Osteoporosis - Thiazide
This study was funded by the Health Research Council (HRC) of New Zealand.