Oral bisphosphonates, a commonly prescribed osteoporosis drug, is associated with a slightly-elevated risk of developing the rare but serious condition of osteonecrosis of the jaw; nonetheless the risk remains extremely low. The study authors state that these findings, published online in the Journal of Dental Research, should be carefully considered against the large benefit of these drugs to prevent and treat osteoporosis.
The study was funded by the National Institutes of Health and conducted by researchers from the Kaiser Permanente Center for Health Research and HealthPartners Research Foundation. The paper's lead author, Jeffrey Fellows, PhD, said, "Previous studies suggested that about one percent of oral bisphosphonate users may develop osteonecrosis of the jaw, but our study found a much lower rate, less than 0.1%. The risk is still real and patients should take necessary precautions, but they shouldn't be alarmed." Most cases of osteonecrosis of the jaw have been reported in cancer patients taking intravenous bisphosphonates; the risk associated with oral bisphosphonates is less clear. The new paper examined electronic medical records of 572,606 patients from 1995 to 2006. Researchers found 23 cases of osteonecrosis of the jaw, most among patients who were not taking oral bisphosphonates, but had other risk factors including cancer, head and neck radiation therapy, and osteoporosis. Nearly 4% of the patients, or 21,164 people, were prescribed oral bisphosphonates, but only 6 of those patients (about 1: 3,500) developed osteonecrosis of the jaw. Patients taking oral bisphosphonates were 9 times more likely than those who didn't to develop the condition. "Invasive dental procedures may also increase the risk of osteonecrosis of the jaw, so patients who need those procedures may want to get them before starting on oral bisphosphonates," said Dr. Daniel Pihlstrom, a co-author on the study and associate director for Evidence Based Care and Oral Health Research at Permanente Dental Associates. "Patients who are already taking these drugs don't need to stop in order to get dental care, but if they need an invasive dental procedure they should inform their dentist or oral surgeon that they are taking the drugs."
The authors caution that their confidence in the association between oral bisphosphonates and osteonecrosis of the jaw is limited because they found so few cases. The small number of cases also limited their ability to control for other risk factors.
(Source: Kaiser Permanente Center for Health Research, January 14, 2011)