1 April 2007

Preventing osteoporotic fractures: high risk patients most likely to benefit

As treatment for osteoporosis becomes more widely available on the PBS, doctors should pay attention to their patients’ absolute risk of fracture, according to the latest edition of NPS RADAR, which carries a timely review of alendronate (Fosamax).

The higher the absolute risk of fracture, the greater the benefit from treatment. Alendronate has been shown to reduce the risk of fracture in those at high risk because of old age and low bone mineral density (BMD) — but without an existing fracture — as well as those with a previous fragility fracture. People with low risk are less likely to benefit and hence treatment is not subsidised.

Previously, PBS treatment for osteoporosis was only available to people with osteoporosis who had already sustained a fracture. From 1 April, treatment will be subsidised for people without fracture who are aged 70 years or older who have BMD T-scores of –3.0 or less.

Fractures may still occur with the use of alendronate. In the Fracture Intervention Trial, women without existing vertebral fractures who took alendronate reduced their risk of some types of fracture, such as hip fracture, but they remained at risk of clinically diagnosed vertebral and wrist fractures.

NPS RADAR also recommends that doctors consider other risk factors for fracture, some of which are independent of BMD and may not be modified by alendronate.

“Prescribers and patients should think about how they can modify risk factors for fractures, for example preventing falls, lowering alcohol intake, stopping smoking and ensuring adequate calcium and vitamin D intake.” Professor Terry Diamond said.

Professor Diamond is one of a panel of independent professionals who gave expert input to the review. He is Associate Professor of Clinical Medicine at the University of New South Wales.

The optimal treatment duration for alendronate has not been agreed. There is some data to suggest it can be stopped after five years in people who respond well to treatment.

NPS RADAR encourages doctors to educate patients about adverse effects of bisphosphonate treatment to reduce the risk of effects such as nausea, vomiting and diarrhoea and serious oesophageal adverse effects.

The importance of maintaining good oral hygiene while on the medication is highlighted because of the rare but serious adverse effect of osteonecrosis of the jaw.

National Prescribing Service Limited (NPS) is an independent, non-profit organisation for Quality Use of Medicines. We provide accurate, balanced, evidence-based information and services to help people choose if, when and how to use medicines to improve their health and well-being. We are member-based and work in partnership with health professionals, government, pharmaceutical industry and consumers. NPS is funded by the Australian Government Department of Health and Ageing.

NPS RADAR provides independent information about new medicines and changes to PBS listings important to GPs, pharmacists and other health professionals involved in primary care management of patients.