Newswise — WASHINGTON – According to research presented this week at the American College of Rheumatology Annual Meeting in Washington, D.C., the risk of atypical fractures from taking bisphosphonates in people with osteoporosis is low.
Osteoporosis is a silent disease of the bones that makes them weak and prone to fracture. By the mid-thirties, most people begin to gradually lose bone strength as the balance between losing bone (resorption) and adding new bone (formation) shifts, so that more bone is lost than can be replaced. As a result, bones become thinner and structurally weaker. Bisphosphonates are a type of medication commonly used to treat osteoporosis and prevent osteoporotic fractures.
Previous reports have raised concerns that long-term treatment of osteoporotic patients with bisphosphonates might cause unusual types of fractures in the hips and thighs called ‘atypical fractures.’ These studies have found a wide range of estimates of increased risk of atypical fractures, and many of these reports may have overestimated the risk. These reports have generated significant concern among patients and health care providers, which has slowed the use of this otherwise effective treatment.
Researchers from the Dartmouth-Hitchcock Medical Center, Lebanon, N.H, recently systematically reviewed and summarized studies reporting rates of atypical femoral fractures in people receiving bisphosphonates for osteoporosis. The study was conducted to obtain better fracture risk estimates, so that clinicians and patients could weigh these risks against the benefits and make informed decisions about using bisphosponates.
“Deciding to start a medication for this disease requires weighing the risks and benefits of therapy. To help decision-making, we summarized available studies to describe the absolute risk of atypical fractures,” says John N. Mecchella, DO, MPH candidate at The Dartmouth Institute for Health Policy & Clinical Practice, instructor of medicine and physician at the Dartmouth-Hitchcock Medical Center, Lebanon, N.H.
The research team led by Dr. Mecchella reviewed medical publications from 1948 to 2012 that reported atypical femoral fractures among people with osteoporosis who were taking bisphosphonates. Two hundred and fifty-seven studies were identified, of which 12 met inclusion criteria. Studies that evaluated bisphosphonate usage in patients with cancer were excluded. Among all the included studies, several hundreds of thousands of bisphosphonate-treated patients were followed over a period ranging from less than one to 10 years of bisphosphonate usage. In this group, only 1,440 atypical fractures were identified by disease classification codes – with 160 of those fractures being confirmed by X-ray.
Study results revealed that the atypical fracture risk in bisphosphonate-treated osteoporosis patients is low. For every 10,000 patients, each treated for a year, only two to 30 developed atypical fractures. If just studies that used X-ray confirmation of fractures were looked at the number was even lower at 10 or fewer patients for every 10,000 patients treated for a year.
“While atypical fractures associated with bisphosphonates can occur, their incidence is low, and fear of this rare side effect should not outweigh the known significant benefits of bisphosphonates, which have been proven to reduce fractures from weak bones,” says Dr. Mecchella.
Patients should talk to their rheumatologists to determine their best course of treatment.
The American College of Rheumatology is an international professional medical society that represents more than 9,000 rheumatologists and rheumatology health professionals around the world. Its mission is to advance rheumatology. The ACR/ARHP Annual Meeting is the premier meeting in rheumatology. For more information about the meeting, visit www.acrannualmeeting.org or join the conversation on Twitter by using the official hashtag: #ACR2012.
Learn more about living well with rheumatic disease as well as rheumatologists and the role they play in health care. Also, discover the ACR’s Simple Tasks campaign, which highlights the severity of rheumatic diseases and the importance of early and appropriate referral to a rheumatologist.
Editor’s Notes: John N. Mecchella, DO, MPH will present this research during the ACR Annual Meeting at the Walter E. Washington Convention Center at 9:00-11:00 AM on Tuesday, November 13 in the Poster Hall (Hall B).
Presentation Number: 1974
Incidence of Atypical Femur Fractures Associated with Bisphosphonate Use for Osteoporosis: A Systematic Review of the Literature
John N. Mecchella (Dartmouth Hitchcock Medical Center, Lebanon, N.H.) John A. Batsis (Dartmouth Hitchcock Medical Center, Lebanon, N.H.) Robin J. Larson (The Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, N.H)Gautham Suresh (Dartmouth Hitchcock Medical Center, Lebanon, N.H.)
Background/Purpose: Reports of a link between bisphosphonate use in patients with osteoporosis and atypical femoral fractures--those occurring in subtrochanteric or diaphyseal locations--have generated significant concern among patients and providers. Attempts to estimate the degree of increased risk have varied widely with OR’s ranging from 1 to 46. In addition, clinicians and patients may be overestimating the absolute risk of atypical fracture when considering these highly effective drugs. To obtain better estimates of these rates and assist clinicians in determining the risk versus benefits, we systematically identified and summarized studies reporting rates of atypical femoral fractures in subjects receiving bisphosphonates for osteoporosis. Methods: With assistance of a reference librarian, we searched MEDLINE (1948-2012), and the Cochrane Library (2012) for studies that reported incidence of atypical femoral fractures among subjects exposed to bisphosphonates for osteoporosis. We also reviewed reference lists and consulted with experts. We excluded studies evaluating bisphosphonates in malignancy. We used no language restrictions. Two reviewers independently extracted data. Disagreements were resolved through consensus. Fracture rates were summarized according to study characteristics.
Results: Of 257 initial studies identified, 12 met all inclusion criteria and included three randomized controlled trials, six retrospective cohorts, and three population-based case-control studies. Among a total of 205,466 subjects followed over a range of less than 1 to 10 years of bisphosphonate exposure, there were 1440 subtrochanteric or diaphyseal fractures identified by ICD-9 or 10 coding, of which 160 were also confirmed radiographically. The incidence of atypical femoral fractures per 1000 patient-years of treatment with a bisphosphonate for osteoporosis ranged from 0.02 to 1 in studies that required radiographic verification of atypical nature, 0.23 to 3.4 in observational studies or randomized controlled trials, and 1.55 to 3.4 in studies of secondary prevention. Conclusion: Currently available evidence suggests the incidence of atypical femoral fractures among patients receiving bisphosphonates for osteoporosis is low. In addition, even at the highest reported estimate of 3.4 per 1000 patient-years, the rate is considerably lower than estimates for recurrent osteoporotic fractures, which occur at approximately 100 per 1,000 patients per year. Discussions regarding bisphosphonate therapy should put both benefits and harms in appropriate context so that decisions are driven by evidence, not fear.
Disclosure: John N. Mecchella, None. John A. Batsis, None. Robin J. Larson, None. Gautham Suresh, None