Background We have often found that markers of inflammation such as elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) do not match in the routine clinical management of rheumatoid arthritis (RA). Different cutoff values for DAS28 CRP and ESR have been recommended.
Objectives To determine factors that affect the interpretations and clinical significance of ESR and CRP values in RA.
Methods The prospective cohort TOMORROW (TOtal Management Of Risk factors in Rheumatoid arthritis patients to lOWer morbidity and mortality; clinical trial registration number, UMIN000003876) study was started in 2010. The study includes 208 patients with RA (112 and 96 treated with biological agents and conventionally, respectively) and 205 age- and sex-matched healthy volunteers (total participants, n=413). Levels of ESR, CRP, hemoglobin (Hb), RF and MMP-3 were measured and RA activity was evaluated using DAS28-ESR and DAS28-CRP.
Results Although CRP was not elevated in any of the volunteers, 43.9% had a high ESR, particularly among those with anemia. Among the patients with RA, ESR and CRP disagreed in 41.3% (elevated ESR/normal CRP in 96.5%). The Hb value was significantly lower (12.5 mg/dL) in the group with elevated ESR/normal CRP values than in that with normal ESR/normal CRP (13.6 mg/dL). No differences in anemia, disease duration, CRP, RF, MMP-3, DAS28-ESR and mHAQ were observed between groups of RA patients with normal Hb or anemia, but ESR was significantly higher in that with anemia.
Conclusions Anemia affects ESR more than CRP. This might indicate that more active disease causes anemia. When inflammation or disease activity is evaluated in patients with RA, the presence of anemia should be considered. When patients are anemic, CRP seems to be more appropriate for evaluating inflammation.
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Disclosure of Interest T. Okano: None Declared, T. Koike Grant/Research support from: Takeda Pharmaceutical, Mitsubishi Tanabe Pharma Corporation, Chugai Pharmaceutical, Eisai, Abbott Japan, Teijin Pharma, Banyu Pharmaceutical and Ono Pharmaceutical, M. Tada: None Declared, Y. Sugioka: None Declared, K. Mamoto: None Declared, S. Wakitani: None Declared, H. Nakamura Grant/Research support from: Chugai Pharmaceutical, Astellas Pharma Inc.,Janssen Pharmaceutica, GlaxoSmithKline, Pfizer Inc. and Daiichi Sankyo, INC., Speakers Bureau: Ono Pharmaceutical