NEW YORK (Reuters Health)—More than 40% of patients with early inflammatory back pain suggestive of axial spondyloarthritis (SpA) show bone loss over the course of two years, according to French researchers.
SpA is known to be associated with bone loss at the spine and the hip and an increased risk of vertebral fractures. To investigate further, Dr. Karine Briot of Cochin Hospital in Paris and colleagues studied data on 265 patients with inflammatory back pain and symptoms of SpA who were taking part in a prospective study.
All of the patients, whose mean age was about 34 years, had bone mineral density (BMD) measured at baseline and at two years.
At baseline, 14.7% had low BMD (defined as a Z-score of -2 or less), the researchers report in Rheumatology, online Sept. 11. However, at two years, 42.3% showed significant bone less.
Overall, 70.6% of patients used NSAIDs at baseline. Such use was associated with significantly less hip bone loss (odds ratio, 0.38). In fact, in those who did not receive anti-TNF therapy, the odds of hip bone loss associated with baseline use of NSAIDs were reduced by 91% (OR, 0.09).
A two-year body mass index (BMI) increase also was tied to a protective effect against bone loss (OR, 0.55). However, a two-year increase in fat mass was associated with hip bone loss (OR, 1.18).
In anti-TNF users, BMD significantly increased at the lumbar spine and did not change at the hip site from baseline. In fact, say the researchers, “Even a short duration of anti-TNF therapy has a positive effect on lumbar spine and hip bone density.”
Despite the limitations of observational studies, Dr. Briot told Reuters Health by email that “Anti-TNF therapy is protective against bone loss and baseline use of NSAIDs has a positive effect on hip bone loss illustrating that the use of drugs effective against inflammation could prevent bone loss.”