Effect of potassium citrate on bone density, microarchitecture, and fracture risk in healthy older adults without osteoporosis: a randomized controlled trial.
CONTEXT
The acid load imposed by a modern diet may play an important role in the pathophysiology of osteoporosis.


OBJECTIVE
Our objective was to evaluate the skeletal efficacy and safety and the effect on fracture prediction of K-citrate to neutralize diet-induced acid loads.


DESIGN AND SETTING
We conducted a randomized, double-blind, placebo-controlled trial at a teaching hospital.


SUBJECTS
Subjects included 201 elderly (>65 yr old) healthy men and women (t-score of -0.6 at lumbar spine).


INTERVENTION
Intervention was 60 mEq of K-citrate daily or placebo by mouth. All subjects received calcium and vitamin D.


OUTCOME MEASURES
The primary outcome was change in areal bone mineral density (aBMD) at the lumbar spine by dual-energy x-ray absorptiometry after 24 months. Secondary endpoints included changes in volumetric density and microarchitectural parameters by high-resolution peripheral quantitative computed tomography in both radii and both tibiae and fracture risk assessment by FRAX (Switzerland).


RESULTS
K-citrate increased aBMD at lumbar spine from baseline by 1.7 ± 1.5% [95% confidence interval (CI) = 1.0-2.3, P < 0.001] net of placebo after 24 months. High-resolution peripheral quantitative computed tomography-measured trabecular densities increased at nondominant tibia (1.3 ± 1.3%, CI = 0.7-1.9, P < 0.001) and nondominant radius (2.0 ± 2.0%, CI = 1.4-2.7, P < 0.001). At nondominant radius, trabecular bone volume/tissue volume increased by 0.9 ± 0.8%, (CI = 0.1-1.7), trabecular thickness by 1.5 ± 1.6% (CI = 0.7-2.3), and trabecular number by 1.9 ± 1.8% (CI = 0.7-3.1, for all, P < 0.05). K-citrate diminished fracture prediction score by FRAX significantly in both sexes.


CONCLUSIONS
Among a group of healthy elderly persons without osteoporosis, treatment with K-citrate for 24 months resulted in a significant increase in aBMD and volumetric BMD at several sites tested, while also improving bone microarchitecture. Based on the effect on fracture prediction, an effect on future fractures by K-citrate is possible.