Factors associated with increase of Hb levels after biologic therapies.

Association between the increase of Hb levels and characteristics of the patients were assessed by Spearman's rank test. Clinical response to biologic therapies was assessed by the reduction of CDAI, CRP, or mHAQ from baseline to week 12, (ΔCDAI  =  CDAI at baseline – CDAI at week 12, ΔCRP  =  CRP at baseline – CRP at week 12, and ΔmHAQ  =  mHAQ at baseline – mHAQ at week 12, respectively). ρ represents Spearman's rank correlation coefficient; RA, rheumatoid arthritis; BMI, body mass index; eGFR, estimated glomerular filtration index; Hb; hemoglobin, RBC; red blood cell count; MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin; LHD%, low hemoglobin density, CDAI, clinical disease activity index; CRP, C-reactive protein; mHAQ, modified health assessment questionnaire-disability index; NSAIDs, non-steroidal anti-inflammatory drugs.