Effect of anti-rheumatic treatment on selenium levels in inflammatory arthritis.

OBJECTIVES

The reason for increased cardiovascular risk in inflammatory arthritis (IA) is unclear. Interestingly, selenium-deficiency is suspected to contribute to the development of cardiovascular disease (CVD) in the general population. Although the reference range of serum selenium (s-selenium) is 50-120 μg/L, there are indications that levels up to 85 μg/L might not be sufficient for optimal cardioprotection. Our aim was to examine s-selenium levels in rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS), to evaluate the effect of anti-rheumatic treatment on s-selenium levels, and to assess relationships between s-selenium levels and clinical and laboratory parameters including markers of disease activity and CVD risk.

METHODS

We examined 64 patients with RA, 40 with PsA and 26 with AS starting with methotrexate (MTX) monotherapy or anti-tumor necrosis factor therapy (anti-TNF) with or without methotrexate (anti-TNF ± MTX) due to active disease. S-selenium, inflammatory biomarkers, endothelial function (EF) and other variables were examined at baseline and after 6 weeks and 6 months of treatment.

RESULTS

In the total IA group, s-selenium increased within 6 weeks of anti-rheumatic treatment, and thereafter the levels remained stable until the end of the 6 months follow-up period. There were no significant differences in s-selenium changes between the three diagnostic groups and between the two treatment regimens. Changes in s-selenium were negatively related to changes in C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), but there were no significant relationships to any other of the examined risk parameters for CVD including EF.

CONCLUSION

IA patients had s-selenium within the reference range, but below the level that might be necessary for optimal CVD protection. Anti-rheumatic treatment had a relatively rapid and sustained effect on s-selenium levels. The increase in s-selenium was related to reduction in inflammatory activity. In theory, anti-rheumatic drugs might improve s-selenium levels through inhibition of pro-inflammatory processes or through other mechanisms. Although we have not revealed any significant relationships between s-selenium and CVD risk parameters, the role of suboptimal s-selenium levels in pathogenesis of premature CVD in IA cannot be ruled out.