“When we think about bisphosphonates, we have to think about whether they are good players or bad players,”, of Harvard Medical School, Boston, said in a virtual presentation at the annual Perspectives in Rheumatic Diseases held by Global Academy for Medical Education.
Although bisphosphonates are a first-line treatment for many patients to reduce fracture risk, rheumatology patients have distinct concerns about these medications, said Dr. Bolster, who is director of the Rheumatology Fellowship Training Program at Massachusetts General Hospital, Boston, and medical lead for the Fracture Liaison Service there.
She shared her insights on four questions most often asked by patients in her practice:
How long do I need to take this medication?
When discussing bisphosphonates with a patient for the first time, “I typically start with the benefits, and include the risks,” she said. “Then I outline my plans for treatment, which would include treatment duration.”
Setting expectations with the patient about planned duration of therapy, reviewing risks and benefits, and preparing to be flexible if changes are needed can help relieve patients’ concerns, she said.
For example, in a hypothetical case of a 69-year-old woman with a 17% chance of a major osteoporotic fracture and 3.8% chance of hip fracture in the next 10 years based on FRAX scores, Dr. Bolster said she would treat with alendronate or zoledronic acid.
Duration must be a clinical decision individualized to the patient, she noted. Research studies support that some patients benefit from a longer duration of therapy. In the Fracture Intervention Trial (FIT) Long-Term Extension, which included 1,099 women, the risk of clinical vertebral fractures significantly declined with 10 years of alendronate treatment, compared with 5 years of treatment, she said.
In the HORIZON trial of 1,233 postmenopausal women, the risk of new morphometric vertebral fractures was significantly lower in those treated with IV zoledronic acid for 6 years versus those treated for 3 years. These studies support that patients at particularly high risk for vertebral fractures may benefit from a longer duration of bisphosphonate therapy, she said.
What should I know about infusion side effects?
Infusion side effects remain a concern, and the acute phase reaction of zoledronic acid occurs in about 30% of patients, but most of these are mild and not recurring, Dr. Bolster said. “I tell patients that 90% report mild to moderate infusion side effects, and that it usually occurs only with the first infusion,” she noted.
To potentially prevent an acute-phase reaction, Dr. Bolster has advised patients to take acetaminophen prior to infusion. “I would tend to recommend acetaminophen over NSAIDs to avoid gastric and renal toxicities,” she said.
“Determining the risks of atypical femoral fractures are challenging” but are another potential side effect that worries patients, she said. An atypical femoral fracture (AFF) is a femur fracture in the proximal third of the shaft, she said.
AFF may occur in patients with osteoporosis even in the absence of bisphosphonate use, Dr. Bolster noted. However, AFF “may occur at increased frequency in those patients with osteoporosis and prolonged bisphosphonate use,” she said. AFF is rare overall, and known risk factors include Asian race (in North America), as well as femoral bowing and glucocorticoid use, she said.
A 2019 meta-analysis favored fracture prevention benefits over potential risk associated with bisphosphonate use. Predicting the risk of AFF remains difficult given several factors, including the low incidence of AFF, the unavailability of radiographs in all studies, not accounting for potential confounding by indication in some studies, and lack of adjustment for low bone mineral density or fracture risk, she added.
Osteonecrosis of the jaw has been linked to bisphosphonate use, and some patients ask about it, Dr. Bolster said. Current data show an incidence of 1 in 10,000 to 1 in 100,000 in patients with osteoporosis, while the incidence in the general population is 1 in 100,000, she noted. The highest risk is associated with use of IV bisphosphonates, although it does occur in patients on oral bisphosphonates and denosumab (Prolia), she added. Given the relatively low risk, the American Dental Association states that there is “no need to discontinue bisphosphonates prior to procedures.” Based on current evidence, bisphosphonate treatment outweighs the low risk of medication-related osteonecrosis of the jaw in patients in need of osteoporosis treatment because of the high risk of fragility fractures in the osteoporosis population, she emphasized.
When will I need another dual x-ray absorptiometry scan?
Osteoporosis develops in fewer than 10% of older postmenopausal women using a 15-year screening interval for those with normal bone mineral density or mild osteopenia at an initial scan, with T-scores of –1.49 or higher, she noted. Therefore, the need for repeat dual x-ray absorptiometry (DXA) scans should be individualized, so some patients with normal bone density or osteopenia and few comorbidities and risk factors for osteoporosis may not need frequent DXA scans, she added.
Although little evidence exists to specifically demonstrate the value of monitoring bone mineral density during a 5-year drug treatment period, as is noted by the American College of Physicians 2017 clinical practice guideline published in, Dr. Bolster said that a DXA scan showing loss of bone mineral density during treatment could indicate incorrect drug use or noncompliance, or a secondary cause for bone loss that may otherwise go unnoticed. For IV zoledronic acid in particular, a DXA scan at 3-4 years can determine whether a drug holiday is warranted, or for patients with severe osteoporosis, whether another 3 years of treatment is necessary. She suggested considering a DXA scan at 2-3 years with alendronate and at 3-4 years with IV zoledronic acid.
Will I need a new medication if I fracture while on treatment?
For patients who ask whether to change medications following a new fracture, Dr. Bolster said it is important to evaluate the patient’s compliance with the treatment regimen and also consider the presence of secondary causes of bone loss. Consideration can be given to keeping the patient on the same regimen because osteoporosis treatment regimens have demonstrated a 50%-70% fracture-risk reduction so they do not prevent all fractures, she said. “It is therefore reasonable, after confirming compliance and ruling out secondary causes of bone loss, to keep a patient on the same regimen following a fracture. For patients using denosumab, there is an increased risk of rapid bone loss and sustaining multiple vertebral fracture with missed doses or discontinuation,” she said.
It is important to evaluate patients who fracture while on therapy for secondary causes of bone loss, assess compliance, and consider strategies such as modifying the route of administration, seeking a different mechanism of action, or continuing on the same regimen, Dr. Bolster noted.
Dr. Bolster disclosed participation in clinical trials for Corbus, Cumberland, and Genentech, as well as research grants from the Rheumatology Research Foundation. She also disclosed serving on advisory boards for Gilead Sciences and Clinical Learning Designs, serving on the American College of Rheumatology’s Committee on Marketing and Communications, and holding investments in Johnson & Johnson.
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