The study produced several notable findings. First, the spine and hip BMD was lower at baseline in patients with erosive disease than in those without. Second, there were no significant changes in BMD at the hip or spine over the year follow-up in patients taking infliximab. Third, the soluble RANKL decreased during the follow-up period, whereas OPG remained stable, resulting in a reduced RANKL/OPG ratio. Fourth, patients with a good response to infliximab according to EULAR criteria had a statistically significant improvement in hip BMD compared with those with less than a good response. The same trend was observed with spine and hand BMD, but these were not statistically significant.
Important limitations of the study include the lack of detailed information about glucocorticoid use (just reporting whether or not they were used, not obtaining cumulative dosage data), the substantial dropout because of inadequate response to infliximab, and the lack of a group without infliximab exposure. The authors suggest that infliximab arrested generalized bone loss but this is really impossible to say based on their study design.
The relationship between generalized bone disease and RA is receiving increased attention. It may be possible that treatments for RA, such as TNFa antagonists, not only improve disease activity but also improve BMD. It is also possible that they improve BMD through a positive effect on weight-bearing activity. At this point, I will continue to aggressively screen and treat patients with RA for osteoporosis. Several treatments have been shown to prevent secondary fractures, including bisphosphonates. Calcium and vitamin D should be strongly considered for most patients with RA. A bisphosphonate may be considered in patients with a known minimal trauma fracture, osteoporosis by BMD testing, or chronic glucocorticoid use with osteopenia.
