Increase of body mass index in a tight controlled methotrexate-based strategy with prednisone in early rheumatoid arthritis: side effect of the prednisone or better control of disease activity?

OBJECTIVE: To clarify whether increase of body weight in patients with early rheumatoid arthritis (RA) upon administration of prednisone is a side effect of prednisone or a result of better control of disease activity, we examined the association of prednisone and disease activity with a subsequent change in body mass index (BMI).

METHODS: In the Computer Assisted Management in Early Rheumatoid Arthritis Trial-II, patients ages >/=18 years with early RA (disease duration <1 year and no prior use of disease-modifying antirheumatic drugs) had been randomized to a methotrexate (MTX)-based tight control strategy with either 10 mg of prednisone (MTX + prednisone) or placebo (MTX + placebo). The MTX + prednisone group had lower disease activity, but gained more weight than the MTX + placebo group (mean +/- SD 2.9 +/- 4.2 kg versus 1.3 +/- 5.3 kg; P = 0.03). Data from patients with monthly measurements of disease activity (Disease Activity Score in 28 joints [DAS28]) and BMI were analyzed with a longitudinal regression (mixed model) analysis with BMI as the dependent variable and treatment strategy and DAS28 as the independent variables, correcting for baseline BMI and possible confounders (sex, age, and rheumatoid factor status).

RESULTS: There was no independent association of glucocorticoid therapy with a change in BMI, but a lower DAS28 was associated with an increased BMI 6 months later. The association of the DAS28 with BMI was most strongly present in postmenopausal women. Clinical cutoff points showed a clear association between DAS28 level and the change in BMI 6 months later.

CONCLUSION: Weight gain during treatment with prednisone seems attributable to a reduction of disease activity and is probably, at least partly, regained weight.