OSTEOPOROSIS

When to begin treatment

The new NOF guidelines advise the practitioner to:

• check for secondary causes of osteoporosis
• recommend BMD testing for women 65 years and older, for younger postmenopausal women when the risk-factor profile raises concern, and when there is a history of fracture
• initiate treatment in women who have had hip or vertebral fracture
• initiate treatment in women who have a DXA-based T-score ≤-2.5 at the femoral neck, total hip, or spine
• initiate treatment in postmenopausal women who have low bone mass (T-score >-2.5 but <-1.0) and a 10-year risk of hip fracture ≥3% or a 10-year probability of any major osteoporosis-related fracture >20%, based on the US-adopted WHO absolute fracture risk model
• measure BMD in DXA centers that use accepted quality assurance measures appropriate for monitoring bone loss every 2 years. For patients on pharmacotherapy, DXA BMD testing is typically performed 2 years after initiating therapy and at 2-year intervals thereafter.

New determinants of treatment

These guidelines replace earlier ones in which all postmenopausal women who had a T-score <-2.0 and those who had a T-score <-1.5 “with risk factors” were candidates for therapy.

Treatment shifts to older population

The new guidelines will probably shift some treatment from younger patients who have a modestly reduced BMD to an older population more likely to have a higher risk of fracture.

For example, consider the following patient—a 52-year-old Caucasian woman who:

• is 5 ft 4 in tall and weighs 130 lb
• has no family or personal history of fracture
• doesn’t smoke or use alcohol excessively
• doesn’t use glucocorticoids
• has no rheumatoid arthritis
• has a femoral-neck T-score of -2.1.

She has a 10-year risk of hip fracture of 1.5% and an 8.5% risk of any major osteoporotic fracture. Therefore, she is no longer a candidate for pharmacotherapy. (Under the previous guidelines, she was.)

Conversely, a 77-year-old woman who has the same height, weight, and history and a T-score of the femoral neck of -1.4, has a 10-year risk of hip fracture of 2.7% and a 23% risk of any major osteoporotic fracture. She is now a candidate for pharmacotherapy. (Under the previous guidelines, she was not a candidate.)

How to counsel the patient

The updated guidelines also include a range of recommendations on what information to include in patient counseling:

• the risk of osteoporosis and related fracture
• the need to get adequate calcium (1,200 mg/day) and vitamin D (800 to 1,000 IU/day)
• the importance of regular weight-bearing and muscle-strengthening exercise to reduce the risk of fall and fracture
• the need to avoid smoking and excess alcohol intake.

Oral bisphosphonates and atrial fibrillation—is there a link?

Heckbert SR, Li G, Cummings SR, Smith NL, Psaty BM. Use of alendronate and risk of incident atrial fibrillation in women. Arch Intern Med. 2008;168:826–831.

Black DM, Delmas PD, Eastell R, et al, for the HORIZON Pivotal Fracture Trial. Once-yearly zoledronic acid for treatment of postmenopausal osteoporosis. N Engl J Med. 2007;356:1809–1822.

Sørensen HT, Christensen S, Mehnert F, et al. Use of bisphosphonates among women and risk of atrial fibrillation and flutter: population-based case-control study. BMJ. 2008;336:813–816.

Postmenopausal women who have osteoporosis and are treated with once-yearly IV zoledronic acid have a higher risk of serious atrial fibrillation than nonusers do, according to a recent publication from the Health Outcomes and Reduced Incidence with Zoledronic Acid Once Yearly (HORIZON) trial. This finding was unexpected and had not been recognized previously. But does it indicate elevated risk with oral bisphosphonate use?

In the Fracture Intervention Trial (FIT) of alendronate for patients who have osteoporosis, the risk of serious atrial fibrillation was higher in alendronate recipients (1.5%, n=47) than in nonusers (1.0%, n=31).¹ However, this difference did not quite reach statistical significance (p=.07).

One case-control study points to 3% risk

The findings in regard to annual infusion of zoledronic acid prompted further evaluation of oral bisphosphonates. Heckbert and colleagues conducted a population-based case-control study at Group Health, an integrated health-care delivery system in Washington state, and estimated that 3% of incident atrial fibrillation might be explained by alendronate use.

Over 3 years, they identified 719 women who had a confirmed history of atrial fibrillation and 966 controls who did not, selected at random from the Group Health enrollment but matched for age and presence or absence of treated hypertension. More atrial fibrillation case patients than controls had ever used alendronate (6.5% [n=47] vs 4.1% [n=40]; p=.03).

Compared with never users of any bisphosphonate, those who had used alendronate had a higher risk of incident atrial fibrillation (odds ratio, 1.86; 95% confidence interval [CI], 1.09–3.15) after adjustment for matching variables, a diagnosis of osteoporosis, and history of cardiovascular disease.