Is Anti–Citrullinated Protein Antibody–Positive Rheumatoid Arthritis Still a More Severe Disease Than Anti–Citrullinated Protein Antibody–Negative Rheumatoid Arthritis? A Longitudinal Cohort Study in Rheumatoid Arthritis Patients Diagnosed From 2000 Onward

Objective Because of its association with joint destruction, anti–citrullinated protein antibody (ACPA)–positive rheumatoid arthritis (RA) is considered to be more severe than ACPA‐negative RA. Clinically relevant joint destruction is now infrequent thanks to adequate disease suppression. According to patients, important outcomes are pain, fatigue, and independence. We evaluated whether ACPA‐positive RA patients diagnosed during or after 2000 have more severe self‐reported limitations and impairments, including restrictions at work, than ACPA‐negative RA patients. Methods A total of 492 ACPA‐positive and 450 ACPA‐negative RA patients who fulfilled the 2010 criteria and were included in the Leiden Early Arthritis Clinic cohort during or after 2000 were compared for self‐reported pain, fatigue, disease activity, general well‐being (measured by numerical rating scales), physical function (measured by the Health Assessment Questionnaire), and work restrictions, including absenteeism at baseline and during the 4‐year followup. Linear mixed models were used. Results At disease presentation, ACPA‐negative patients had more severe pain, fatigue, self‐reported disease activity scores, and functional disability (P < 0.05), although absolute differences were small. During followup, ACPA‐negative patients remained somewhat more fatigued (P = 0.002), whereas other patient‐reported impairments and limitations were similar. Thirty‐eight percent of ACPA‐negative and 48% of ACPA‐positive patients reported absenteeism (P = 0.30), with median 4 days missed in both groups in the last 3 months. Also, restrictions at work among employed patients and restrictions with household work were not statistically different at baseline and during followup. Conclusion In current rheumatology practice, ACPA‐positive RA is not more severe than ACPA‐negative RA in terms of patients’ relevant outcomes, including physical functioning and restrictions at work. This implies that efforts to further improve the disease course should be proportional to both disease subsets.