Hormone therapy stabilized bone loss over a 2-year period in rheumatoid arthritis patients, as measured on digital x-ray radiogrammetry, according to a study published in Annals of the Rheumatic Diseases.
The study is important not only for finding that hormone therapy (HT) was effective, but because it depended on readings that detected losses of as little as 0.36%.
In contrast, plain radiographs, "the standard method for detection and quantification of joint destruction in RA," cannot detect bone loss of less than 30%, wrote Dr. Helena Forsblad-d’Elia and Dr. Hans Carlsten (Ann. Rheum. Dis. 2010 Nov. 3 [doi: 10.1136/ard.2010.137133]).
Dr. Forsblad-d’Elia and Dr. Carlsten, both of the center for bone and arthritis research at the University of Gothenburg (Sweden), looked at 88 postmenopausal women with radiographic joint destruction due to rheumatoid arthritis. Findings from earlier research by Dr. Forsblad-d’Elia has shown that RA is strongly associated with generalized osteoporosis (Ann. Rheum. Dis. 2003;62:617–23).
Patients were randomized to one of two groups. The first received HRT, which consisted of estradiol and norethisterone acetate, plus a daily dose of 500 mg calcium and 400 IU vitamin D. Controls received only the calcium and vitamin D.
Patients had digital x-ray radiogrammetry–bone mineral density (DXR-BMD) readings at baseline and at 2 years. A total of 13 women had ineligible DXR-BMD readings at baseline because of prostheses, osteosynthetic materials, the position of the hands or insufficient x-ray, wrote the authors. Another 25 patients did not complete the second DXR-BMD 2 years later.
That left a total of 50 women (23 HRT patients, 27 controls) to be included in the study analysis. The mean age of both groups was roughly 58 years, and both groups had a mean disease duration of greater than 10 years.
According to the researchers, at baseline, HT patients and controls had an identical mean DXR-BMD reading of 0.45 g/cm2; HRT patients had a standard deviation of 0.096, vs. 0.081 in the control group.
Two years later, HT patients’ mean reading was identical except for a tiny increase in the standard deviation, to 0.097, whereas control patients’ mean DXR-BMD was 0.44, with a standard deviation of 0.084.
The minute difference was insignificant for the HT group (–0.0015 ± 0.0078), but significant for controls, both in terms of change from baseline and difference from the HT group (–0.18 ± 0.038, P less than .05 for both comparisons).
Put another way, the decrease among HT patients from baseline was 0.36%, while the decrease from baseline for controls was 3.74% – more than 10 times greater.
"DXR-BMD has been proposed to be an outcome measure in monitoring treatments in early RA, and can predict future radiographic joint damage," concluded the authors. "So far, there is limited knowledge of DXR-BMD used as an outcome measure in randomized controlled trials in long-term RA."
Based on the current data, however, "we suggest that DXR-BMD could serve as an outcome measure in [randomized controlled trials] in long-standing RA," they wrote.
"Further studies on disease-modifying drugs are needed to assess its usability."
Dr. Forsblad-d’Elia and Dr. Carlsten said that this study was supported by several grants from rheumatology and other foundations; they added that they had no competing interests to disclose.