Laboratory characteristics of a cohort of patients with early rheumatoid arthritis.

Introduction/objective: To characterize a population of patients with early rheumatoid arthritis (RA) according to laboratory aspects, comparing it with other similar cohorts.

Methods: Data presented are part of a prospective incident cohort study that evaluated 65 patients with early RA, followed for 36 months from the diagnosis at Early Rheumatoid Arthritis Clinic of Hospital Universitário de Brasília (HUB). We recorded demographics, clinical, and laboratory data relevant to the cohort initial assessment, including red blood cells, evidence of inflammatory activity, and presence of autoantibodies (rheumatoid factor (RF)), cyclic citrullinated peptide antibodies (anti-CCP), and antivimentin citrullinated (anti-Sa).

Results: There was a preponderance of female (86%) with mean age of 45.6 years. Twelve patients (18.46%) had laboratory diagnosis of anemia (hemoglobin < 12 g / dL). Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were above the reference value for 51 (78.46%) and 46 (70.76%) patients, respectively. Thirty-two patients (49.23%) were positive for at least one of the RF isotypes, and 28 patients (43.07%) were positive for IgA RF, 19 (29.23%) for IgG, and 32 ( 49.23%) for IgM RF, respectively; 34 patients (52.30%) were positive for at least one of the techniques used in investigation of anti-CCP (CCP2, or CCP3, or CCP3.1), while 9 (13,85%) were positive for anti-Sa.

Conclusions: The laboratory characteristics of patients enrolled in this Brazilian cohort are similar in many respects to those of North-American, European, and Latin-American cohorts previously published.