A second bone mineral density (BMD) screening four years after a baseline measurement provided little additional value when assessing risk for hip or other major osteoporotic fracture among older men and women untreated for osteoporosis, and resulted in little change in risk classification used in clinical management, findings that question the common clinical practice of repeating a BMD test every 2 years, according to a study in the September 25 issue of JAMA.
Bone mineral density testing is important in the management of osteoporosis. Guidelines for initiating pharmacologic treatment for osteoporosis are based on BMD in conjunction with risk classification scores. “Despite the utility of BMD, the value of repeating a BMD screening test is unclear,” according to background information in the article. Currently, Medicare reimburses for BMD screening every 2 years regardless of baseline BMD and without a restriction on the number of repeat tests. Twenty-two percent of screened Medicare beneficiaries receive a repeat BMD test within 3 years, on average 2.2 years apart. “Given the priority of reducing health care costs while improving quality of care, it is important to determine whether repeat BMD screening is useful.”
Sarah D. Berry, M.D., M.P.H., of the Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, and colleagues conducted a study to determine whether changes in BMD after 4 years provide additional information on fracture risk beyond baseline BMD. The population-based cohort study involved 310 men and 492 women from the Framingham Osteoporosis Study with 2 measures of femoral neck BMD taken four years apart between 1987-1999. The primary measured outcome was risk of hip or other major osteoporotic fracture through 2009 or 12 years following the second BMD measure. Average age was 75 years.
After a median (midpoint) follow-up of 9.6 years, the average BMD change was -0.6 percent per year. During follow-up, 113 participants (14.1 percent) experienced 1 or more major osteoporotic fractures (88 hip, 24 spine, 5 shoulder, and 33 forearm fractures). The net change in the percentage of participants with a hip fracture correctly reclassified with a second BMD measure was 3.9 percent; the net change in the percentage of participants without hip fracture correctly reclassified by a second BMD measure was -2.2 percent. The researchers found that the net change in the percentage of participants with a major osteoporotic fracture correctly reclassified with a second BMD measure was 9.7 percent; the net change in percentage of participants without major osteoporotic fracture correctly reclassified by a second BMD measure was -4.6 percent.
The authors conclude that for older patients not undergoing treatment for osteoporosis, “… BMD change provided little additional information beyond baseline BMD for the clinical management of osteoporosis.” The second BMD measure reclassified a small proportion of individuals, and it is unclear whether this reclassification justifies the current U.S. practice of performing serial BMD tests at 2.2-year intervals. “Further study is needed to determine an appropriate rescreening interval and to identify individuals who might benefit from more frequent rescreening intervals.”