Anticonvulsant medications and thyroid hormone are widely recognized to increase risk. Other important but often overlooked medications include selective serotonin reuptake inhibitors, proton pump inhibitors, aromatase inhibitors, and thiazolidinedione drugs for diabetes.
Whom to treat
BMD is best determined by DEXA measurement at the hip and spine. Peripheral DEXA measurement (finger, forearm, or heel) has been validated for use in women but not in men and is acceptable if central testing is not available.
A T-score ≤-2.5 (2.5 standard deviations below normal BMD for a healthy young adult) establishes osteoporosis in need of treatment, and a score of >-1.0 is considered normal.
T-scores between -1.0 and -2.5 indicate “low bone mass,” or osteopenia, and entail more complex treatment decisions that take into account age and the same risk factors used to select patients for screening.
The NOF guideline endorses the use of the WHO’s Web-based Fracture Risk Assessment Tool (FRAX), which uses BMD and office-assessment information (e.g., family and personal health history) to compute fracture risk. Treatment should be considered for those with a 10-year probability of hip fracture ≥3% or of any major osteoporosis-related fracture ≥20%.
But the FRAX algorithm is not yet incorporated into most DEXA equipment and may be unwieldy and time-consuming for PCPs to use. As a result, in-practice treatment decisions are often still based on clinical judgment.
Along with major risk factors, things like medical history should be weighed, along with BMD, Dr. Cosman says. “The closer your T-score is to -2.5, the fewer risk factors you need.” Patient preferences may alter treatment decisions regardless of estimated fracture risk.
Although risk-factor reduction (i.e., adequate calcium, vitamin D, and exercise) and fall prevention require attention, pharmacotherapy is the mainstay of osteoporosis prevention and treatment in patients with low bone mass judged to be at high risk.
The bisphosphonates alendronate (Fosamax), risedronate (Actonel), ibandronate (Boniva), and zoledronic acid (Reclast) are approved for prevention as well as treatment. Side effects, chiefly GI problems, are similar for all agents in this class.
Estrogen/hormone therapy is approved for osteoporosis prevention in women, but concerns about increased risk of cardiovascular disease, deep venous thrombosis (DVT), and breast cancer have limited its use. The FDA recommends that non-estrogen treatments be considered first.
The estrogen agonist/antagonist raloxifene (Evista) is approved for both prevention and treatment in postmenopausal women. It is not cardiotoxic and reduces breast-cancer risk but carries a risk of DVT comparable to that of hormone therapy
The parathyroid hormone teriparatide (Forteo) is approved for a maximum of two years’ use when the risk of fracture is judged to be high and when osteoporosis is associated with extended glucocorticoid therapy.
Calcitonin (Miacalcin, Fortical) is approved for treatment but is rarely used because of its relatively weak effect, according to Dr. Cosman.
Medication choice should take age, fracture risk, and other considerations into account, she says. A 52-year-old woman one year removed from her last menstrual period who has severe hot flushes, for example, might be prescribed hormone therapy for a few years, then raloxifene, and later a bisphosphonate. A patient with a very low T-score (-3.5) or history of vertebral fracture might be prescribed teriparatide for two years followed by bisphosphonate therapy.
PCPs can manage osteoporosis and low bone mass for the most part, but in more complex cases involving fracture or when the choice of drugs is unclear, referral is probably indicated, concludes Dr. Cosman.