To study low blood hemoglobin concentrations as a predictor of radiographic damage progression in patients with rheumatoid arthritis (RA).
Post hoc analyses were performed in patients from the PREMIER trial with early RA undergoing 2 years of adalimumab (ADA), methotrexate (MTX), or ADA + MTX combination therapy. Low disease activity was defined as a score <3.2 on the 28-joint Disease Activity Score using the C-reactive protein level (DAS28-CRP), and clinical response by the American College of Rheumatology criteria for 20% improvement at week 24. Baseline or mean hemoglobin concentrations over time, or anemia as defined using sex-specific World Health Organization criteria, were analyzed in mixed-effects models for longitudinal data in men and women as predictors of progressive joint damage, as measured by the modified total Sharp/van der Heijde score (ΔSHS). Data were adjusted for treatment and other patient characteristics, including the DAS28-CRP.
Baseline hemoglobin was inversely associated with ΔSHS in adjusted analyses (P < 0.05 for both sexes). Baseline anemia predicted greater ΔSHS in MTX-treated patients over 104 weeks, and in ADA- and combination-treated patients over 26 weeks. Lower hemoglobin concentrations over time, as well as time with anemia, were associated with greater damage progression (P < 0.001). The effect of low hemoglobin concentrations on joint damage progression remained significant, even in patients achieving low disease activity.
Low hemoglobin is a DAS28-CRP-independent predictor of radiographic joint damage progression in MTX-treated patients with early RA. This effect decreases over time in ADA- and combination-treated patients, and in clinical responders irrespective of treatment modality.