Clinical significance of low titer anti-nuclear antibodies in early rheumatoid arthritis: implications on the presentation and long-term course of the disease

The objective of this study was to evaluate the clinical significance of anti-nuclear antibodies (ANA) detected in the early stages of rheumatoid arthritis (RA), by a retrospective comparison of the clinical, laboratory, and therapeutic characteristics of patients with or without ANA. The files of 99 longstanding seropositive RA patients were reviewed. Data relating to demographics, medical history, family history, physical findings, extra-articular complications, laboratory tests, drugs [dosage, duration, efficacy, combinations, adverse effects (AEs)], intra-articular injections, and surgery were recorded. Patients with or without ANA at presentation of their disease were compared using chi-square and t-tests. Fifty-two ANA positive (group 1) and 47 ANA negative (group 2) patients were enrolled in the study. All were comparable in terms of their mean age, age at diagnosis, follow-up duration (∼10.5 years), and male:female (M:F) ratio. On admission, pain complaints were more pronounced in group 1 (P = 0.004 in the feet), but the physical findings did not differ. Deformities and nodules developed in similar numbers. Extra-articular complications were evenly distributed; vasculitis, however, was significantly more prevalent in ANA positive (10/52) than in ANA negative (2/47) patients. Thyroid disease was more common in group 2 (10/47 vs 3/52). Laboratory tests (presentation and maximal values) were similar, with the exception of higher anti-DNA (but within normal ranges) and γ-globulin% in group 1. Group 1 used more drugs prior to diagnosis. Corticosteroids and disease-modifying anti-rheumatic drugs (DMARDs) were evenly used. Combination therapy, joint injections, and surgery were more prevalent in group 2. AEs to various DMARDs were more common in group 1. Although similar in many aspects, RA patients with ANA tend to present with more pain complaints, a higher risk of vasculitis and AEs relating to use of DMARDs, while those without ANA needed more aggressive therapeutic modalities.