Bisphosphonates May Improve Bone Balance in Postmenopausal Women

SEATTLE — Treatment with bisphosphonates may improve bone balance and reduce bone turnover. In addition, bisphosphonates may have different biological effects on bone turnover and bone balance in postmenopausal women compared with healthy premenopausal women, researchers reported.

In their study, they investigated the potential bone balance improvements of bisphosphonates in 165 postmenopausal women and found that at 96 weeks of treatment, bisphosphonates reduced the mean levels of bone turnover to –2.1 standard deviation (SD) units below the mean of premenopausal women (P<.001).

“Basically what we did was to look at the different sort of treatments to see how they do in reducing bone turnover and affecting bone balance. The most interesting thing we found was actually that, in addition to reducing bone turnover, bisphosphonates do improve or make bone balance positive and that is something that has not been looked at before,” said lead study investigator Fatma Gossiel, PhD, who is a research scientist at the University of Sheffield in the United Kingdom.

Dr Gossiel, who presented the study findings at the American Society for Bone and Mineral Research (ASBMR) 2015 Annual Meeting, noted that this study may help better guide clinicians on optimal treatment regimens for preventing osteoporotic fractures in postmenopausal women.

In this study, there were differences between bisphosphonate therapies in terms of their bone strengthening capabilities.

Postmenopausal osteoporosis is characterized by increased bone turnover and a negative balance in terms of bone resorption and bone formation, Dr Gossiel explained.

She and her colleagues prospectively compared the effects of bisphosphonates on bone turnover rates and bone balance in postmenopausal women with osteoporosis using a T-score bone marker plot. They enrolled 165 postmenopausal women (mean age, 67 years).  All women had a hip and spine bone mineral density (BMD) T-score number of –2.5 or lower or a T-score of –1 or lower with a prior fracture. 

All the women were prescribed calcium and vitamin D supplements and then randomly assigned to receive ibandronate 150 mg a month (n=55), alendronate 70 mg a week (n=54), or risedronate 35 mg a week (n=56). The investigators collected fasting serum samples at baseline and weeks 1,2,4,12,13, 48, and 96.

The investigators also included a control group of 200 healthy premenopausal women who received no treatment.

The investigators measured serum procollagen type I N-terminal propeptide (PINP) and serum C-telopeptide of type I collagen (CTX) in order to carefully analyze the bone’s structural matrix. They calculated T-scores for PINP and CTX value for each postmenopausal woman using the mean and SD values from the premenopausal group.

The study revealed that bisphosphonates significantly reduced mean levels of turnover by week 96.

Dr Gossiel said the bone balance was positive for all agents in the early phase of treatment. However, the researchers found significant differences at week 96.  The mean levels of balance were positive in all treatments combined (P<.01), but the benefits seen in overall bone balance were greatest with alendronate (P<.01). 

While the study sample is small, there are significant clinical implications, according to Dr Gossiel.

“Any patients who have disorders that relate to high turnover state could very well use this method that is proposed here. This is particularly true for osteoporosis,” she said in an interview with Endocrinology Advisor.

Reference

1. Gossiel F. Abstract SU0347: The Effect of Bisphosphonate Treatment on Bone Turnover and Bone Balance in Postmenopausal Women with Osteoporosis. Presented at: American Society for Bone and Mineral Research (ASBMR) 2015 Annual Meeting; Oct. 9-12, 2015; Seattle.