Low dose hydrochlorothiazide preserves bone mineral density, according to the
findings of a study in the Annals of Internal Medicine (2000;133:516).
Dr Andrea LaCroix (centre for health studies, Seattle, United States) and colleagues
undertook a trial involving 320 patients aged between 60 and 79 years, who had
a baseline bone mineral density at the hip that was within two standard deviations
of the normal value for their age.
The subjects were randomly assigned into three groups and received either placebo
or hydrochlorothiazide 12.5mg or 25mg daily. The authors found a dose-response
relationship between the percentage change in bone mineral density at the hip
and hydrochlorothiazide treatment. After 36 months of follow-up, bone mineral
density at the hip of the treated group was greater by 0.79 per cent in the
12.5mg group and 0.92 per cent in the 25mg group than that of patients in the
placebo group. The figures at 36 months for the spine were not significantly
different for any of the groups, although a difference between the placebo and
treated groups was found at 6 months.
The authors say that the treatment effects seemed to be stronger in women but
note that there were fewer (115) men in the trial. The magnitude of the benefit
seen with hydrochlorothiazide treatment was modest but, if cumulative over 10
to 20 years, the effects “could possibly explain the one-third reduction
in risk for hip fracture seen in many epidemiologic studies”, they say.