NEW ORLEANS — Bone health experts offered their share of helpful clinical insights at the annual meeting of the International Society for Clinical Densitometry.
Here are some of the highlights:
Low Bone Density in the Young
Low bone density is not uncommon in young adults but—at least in the short-term—does not carry with it the same relative risk of fracture as in older individuals unless secondary causes of metabolic bone disease are identified, said Andrew J. Laster, M.D., who is a rheumatologist practicing in North Carolina.
Secondary causes of low BMD include endocrinopathies (hypercalciuria, hypogonadism, hyperparathyroidism, and Cushing's syndrome), some GI disorders (gastrectomy, inflammatory bowel disease, celiac disease, intestinal bypass surgery, primary biliary cirrhosis, and pancreatic insufficiency), genetic disorders (Ehlers-Danlos syndrome, Marfan syndrome, and homocystinuria), and eating disorders (anorexia nervosa, bulimia nervosa, and female athlete triad).
Ask patients about long-term glucocorticoids, suppressive doses of thyroid hormone, phenytoin, phenobarbital, GnRH agonists, aromatase inhibitors, cyclosporine, aluminum-containing antacids, long-term heparin, and vitamin A supplementation.
The diagnosis of osteoporosis can be made in premenopausal women if they have low BMD as well as secondary causes of the disorder.
Assessing Fracture Risk Factors
Before experts declare the benefits of addressing a particular risk factor in an individual patient, they should stop and ask some key questions, according to John Kanis, M.D., who is the director of the World Health Organization's Collaborating Centre for Metabolic Bone Diseases in Sheffield, England.
Is the risk factor internationally validated? “We need to know that something works as well in Japan as it does in the United States,” Dr. Kanis commented.
Is it feasible for a primary care physician to assess the risk factor? Low calcium intake is a risk factor for hip fracture, but measuring calcium intake is difficult to do.
Is the risk factor intuitive? “Dementia is a very strong risk factor for hip fracture, but it's going to be rather difficult to persuade a primary care physician that if he has a patient with dementia, the first thing he should be thinking about is osteoporosis.
A family history is much more intuitive in medical care,” Dr. Kanis commented at the meeting.
When to Do Vertebral Assessments
Paul Miller, M.D., who is the director of the Colorado Center for Bone Research in Lakewood, recommended that physicians perform a vertebral assessment in patients with any of the following characteristics:
▸ Loss of 1.5 inches or more in height.
▸ Back pain in patients coming to your office for osteoporosis assessment.
▸ Known vertebral deformities or hip fractures.
▸ Chronic glucocorticoid therapy.
▸ Age older than 60 years.
There are a number of potential advantages to using bone turnover markers, according to Douglas C. Bauer, M.D., of the University of California, San Francisco.
These measurements provide a more dynamic assessment of skeletal metabolism than BMD. More importantly, bone turnover markers rapidly reflect changes as a result of therapy, providing a better means of assessing treatment efficacy. The availability of automated assays for a number of the markers allows clinicians to inexpensively assess bone health.
The most significant disadvantage to using clinical markers is that there is typically very high day-to-day variability in the results. Clinical markers can vary by the time of collection. “Right now it's suggested that they be collected in the morning, before 9 o'clock,” said Dr. Bauer.
In addition, just how much variability there is between laboratories performing these assays has yet to be studied. There are no standardized cut points available for bone turnover markers.
For a patient who has been on an antiresorptive therapy and who will be taking teriparatide, there is no need for a break between the two therapies, said John Bilezikian, M.D., professor of medicine and pharmacology at Columbia University, New York.
“I don't see any reason for a drug holiday, even in the case of depressed bone turnover, because eventually the effects of parathyroid hormone will overcome [depressed bone turnover] … in short order,” he said.
For patients who will be starting therapy for low BMD, Dr. Bilezikian recommends monotherapy with either an antiresorptive or with parathyroid hormone.
In addition, “Most of us would agree that after teriparatide, we should follow up with an antiresorptive,” Dr. Bilezikian said at the meeting.