People taking bisphosphonates to treat osteoporosis, the bone disease that leads to increased risk of fracture, are not only surviving well, they are gaining an extra five years of life, said Australian researchers in a study published online this week.

The researchers used data covering April 1989 to May 2007 from a cohort taking part in the long running Dubbo Osteoporosis Epidemiology Study.

The study included 1,223 and women and 819 men aged 60 and over who were living in Dubbo, a semi-urban city of some 32,000 souls in New South Wales.

A sub-group of 121 participants took bisphophonates for an average of 3 years, while other sub-groups were on other treatments like vitamin D (with and without calcium) and hormone therapy.

First author and associate professor Jacqueline Center, and senior and professor John Eisman, from the Garvan Institute of Medical Research in Sydney, found the longer life associated with bisphosphonate treatment was marked and clear.

With other colleagues, they wrote a paper on their findings in the Journal of Clinical Endocrinology and Metabolism, which appeared online on 2 February.

Center told the press that:

“While the results seemed surprisingly good, they are borne out by the data – within the limitations of any study – and appear to apply to men as well as women.”

She said when they first looked at the results they thought there had been an error, or that something had been overlooked.

For example, an obvious factor could be that these participants are people who have gone out of their way to get medical attention and do something about their condition, so this trait could also predispose them to be healthier and live longer.

(Note this was not a randomized controlled trial where participants are randomly assigned to different treatment groups. It was a prospective cohort study, where the researchers simply followed a cohort of people who happened to be having different treatments for the same condition.)

But comparison of the results with similar health-aware participants taking Vitamin D and calcium or women on hormone therapy, “simply confirmed that our results were not skewed by that factor,” said Center.

Center went on to explain that in a group of women aged over 75, with osteoporotic fractures, one would expect about 50% of them to die over a period of 5 years.

But they found:

“Among women in that age group who took bisphosphonates, the death rate dropped to 10%,” said Center.

Also, among younger women with osteoporotic fractures, where one might expect about 20 to 25% deaths over five years, there were no deaths at all, she added, explaining their figures showed this was “consistent with about a 5 year survival advantage for people on bisphosphonates”.

Eisman said they were intrigued by their findings:

“We speculate that it may have something to do with the fact that bone acts as a repository for toxic heavy metals such as lead and cadmium.”

As people get older they lose bone, and this is accompanied by a release of the toxic materials back into the body, which has a negative effect on health.

“By preventing bone loss, bisphosphonates prevent some of this toxic metal release,” said Eisman.

“While we know that this is the case, we don’t yet have evidence that this produces the survival benefit,” he added.

About 2 million Australians have osteoporosis. Eisman said only about one third of women and one in ten men receives treatment for the disease, a situation he describes as “unaccepatable when you consider that people could be helped, and death could be delayed by several years”.

Studies by Garvan show that osteoporotic fractures increase a person’s risk of dying, even after relatively minor fractures if that person is elderly.

“Osteoporosis is a big societal burden and remains a poorly understood and severely undertreated disease in Australia,” said Eisman.

The researchers stressed in their press statement that like any drug, some people can have adverse reactions to bisphosphonates, which should only be used for their approved purpose.

Funds from National Health and Medical Research Council Australia, The Bupa Health Foundation, the Ernst Heine Foundation, and untied grants from Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Servier and Novartis, helped pay for the study.

“Osteoporosis Medication and Reduced Mortality Risk in Elderly Women and Men.”
Jacqueline R. Center, Dana Bliuc, Nguyen D. Nguyen, Tuan V. Nguyen, and John A. Eisman.
The Journal of Clinical Endocrinology & Metabolism, published 2 February 2011.
DOI:10.1210/jc.2010-2730

Additional source: Research Australia (2 Feb 2011 press release).

Written by: Catharine Paddock, PhD