Objectives To investigate changes in bone mineral density (BMD) in patients with early rheumatoid arthritis (RA) over a 10-year period.
Methods Consecutive patients with early RA (symptom duration <12 months) were followed according to a structured programme and examined with dual-energy X-ray absorptiometry (DXA) at inclusion and after 2, 5 and 10 years. Mean Z-scores over the study period were estimated using mixed linear effect models. Changes in Z-scores between follow-up visits were analysed using paired T-tests.
Results At inclusion, 220 patients were examined with DXA. At the femoral neck, the mean Z-score over 10 years was −0.33 (95 % CI −0.57 to −0.08) in men and −0.07 (−0.22 to 0.08) in women. Men had significantly lower BMD at the femoral neck than expected by age at inclusion (intercept Z-score value −0.35; 95 % CI −0.61 to −0.09), whereas there was no such difference in women. At the lumbar spine, the mean Z-score over the study period for men was −0.05 (−0.29 to 0.19) and for women 0.06 (−0.10 to 0.21). In paired comparisons of BMD at different follow-up visits, femoral neck Z-scores for men decreased significantly from inclusion to the 5-year follow-up. After 5 years, no further reduction was seen.
Conclusions In this observational study of a limited sample, men with early RA had reduced femoral neck BMD at diagnosis, with a further significant but marginal decline during the first 5 years. Lumbar spine BMD Z-scores were not reduced in men or women with early RA. Data on 10-year follow-up were limited.
- rheumatoid arthritis (RA)
- bone mineral density
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Contributors LT participated in the study design and the data collection, performed the statistical analyses and wrote the first draft of the manuscript. MW managed the major part of the organisation of data for statistical analysis and participated in the analysis and interpretation of data. JÅN participated in the study design, the development of the patient questionnaires and the statistical analysis and in the analysis and interpretation of data. MK and KEÅ participated in the study design and in the analysis and interpretation of data. LJ participated in the study design, the design of the patient questionnaires and in the analysis and interpretation of data. CT conceived of the study, supervised the data management and the statistical analysis and helped draft the manuscript. All the authors helped in the revision of the manuscript and read and approved the final version.
Funding This work was supported by the Swedish Research Council (2015-02228), the Swedish Rheumatism Association (R-481821), Lund University (ALFSKANE-446501) and Region Skåne (REGSKANE-453511).
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. The datasets generated and/or analysed during the current study are not publicly available due to European Union legislation (the General Data Protection Regulation), but a limited and fully anonymised dataset containing the individual patient data that support the main analyses is available from the corresponding author on reasonable request.
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