Outcome of positive antinuclear antibodies in individuals without connective tissue disease

Abstract

Objective: To determine if individuals with high titer antinuclear antibodies (ANA) but without clinical evidence of connective tissue disease (CTD) subsequently develop CTD or experience a change in ANA positivity.

Methods: We included patients from an initial study database as well as those reviewed in an outpatient rheumatology clinic at the University of Alberta Hospital over the past 8 years. A telephone survey targeting signs and symptoms of CTD was conducted. Serum samples from consenting patients were then assayed for ANA, antibodies to extractable nuclear antigens (ENA), and anti-dsDNA by the Rheumatic Disease Unit at the University of Alberta Hospital.

Results: Sixty-two patients completed the telephone survey and 53 completed both the telephone survey and repeat serological blood investigations. Mean length of followup was 5.4 years, with an age range from 19 to 87 years. Forty-eight of 53 patients (91%) remained ANA positive on repeat testing, and 5 patients were also ENA positive. Three patients had been diagnosed with CTD since the previous study. The most common clinical features on telephone survey included joint pain (34 patients) followed by Raynaud's phenomenon (11 patients).

Conclusion: Patients tended to remain ANA positive on repeat testing. Three out of 53 patients had developed CTD, reflecting the more sensitive but less specific nature of ANA testing. Another common condition associated with ANA positivity was hypothyroidism. Continued longterm followup with larger cohorts is needed.