What we know about bone drug risks and benefits

Tuesday, 29 November 2011 12:24

There are definite benefits to osteoporosis drugs. People who take osteoporosis drugs, regularly and correctly, reduce their risk of having a fracture by about one-third. This is particularly true in patients who are at high risk for having a fracture or who have very low bone density. For people at low risk, fracture protection is not well proven.

There are rare harms that can occur with long-term use of osteoporosis drugs. Estimates are that for each year of use about 1 of every 1,000 patients who take osteoporosis drugs has a harmful side effect. The risk of harm appears to increase the longer a patient stays on the drug, particularly after 4 to 5 years. We will focus on two harmful effects that have received a lot of news coverage recently.

Atypical fracture: One of the harmful effects is a tendency for patients to suffer a fracture, right in the middle of the long thighbone --- with hardly any injury. Many patients who have had these fractures report a deep, aching pain in the middle of the thigh several weeks to months before that bone breaks. The ache is not joint pain and not related to exertion or physical activity.

Osteonecrosis of the jaw: The other harmful effect is a condition where the bones that support the teeth break down and don't heal--- the medical term is osteonecrosis of the jaw (ONJ). ONJ usually occurs after dental procedures like implants or extractions and has been linked to high dosage bisphosphonates used in patients with cancer. ONJ tends to happen in patients who have poor dental health.

Both these harmful conditions are rare — about 1 in 1,000 osteoporosis drug users each year. This is a 0.001% chance and would be similar to reaching into a bag of 999 red balls and pulling out the one blue ball. For people at high risk of fracture, the chance of benefiting from the treatment is many times greater than the harm. Treatment will reduce the risk of a fracture.