Prognostic factors for the development of rheumatoid arthritis and other connective tissue diseases in patients with palindromic rheumatism

Objective. Palindromic rheumatism is characterized by attacks of acute arth ritis of short duration. In the long term, a substantial proportion of pati ents will develop rheumatoid arthritis (RA) or other connective tissue dise ases, but the determinants of subsequent chronic disease have not been adeq uately established. We identify clinical prognostic factors for the develop ment of RA and other connective tissue diseases in patients with palindromi c rheumatism in a retrospective cohort study. Methods. The medical records of 4900 patients with arthritis referred from 1986 to 1996 to 3 rheumatologists at an academic center were reviewed. One hundred sixty patients were diagnosed as having palindromic rheumatism. Aft er review 127 complied with diagnostic criteria for palindromic rheumatism, Disease duration was estimated as time of first attack until the last cons ultation, or the development of RA or other connective tissue disease. Surv ival analysis including Cox regression was used to identify clinical variab les associated with the risk of developing RA or other connective tissue di sease, adjusting for varying disease duration. Results. Sixty-five percent of the patients were female. Age at onset was 4 0 +/- 12 years. Mean disease duration was 6 +/- 6 years, and mean followup by the rheumatologists was 40 +/- 45 months. Joints more frequently affecte d were wrist, knee, and metacarpophalangeal. Forty-three patients (34%) sub sequently developed a connective tissue disease including 36 (28%) RA, 3 (2 %) systemic lupus erythematosus, and 4 (3%) other connective tissue disease s. In the final Cox regression model the hazard ratio for development of a connective tissue disease in the presence of a positive rheumatoid factor ( RF) was 2.9 (p = 0.002), for proximal interphalangeal (PIP) joint involveme nt 2.4 (p = 0.02), for wrist involvement 2.5 (p = 0.05), for female sex 2.2 (p = 0.05), and for age at onset 1.03 (per year) (p = 0,001). Female patie nts with positive RF and involvement of the hands had an 8-fold risk of dev eloping disease, compared with patients with one or fewer of these features . Conclusion. Positive RF and early involvement of the wrist and PIP joints p redict the subsequent development of RA or other connective tissue disease in patients with palindromic rheumatism, and identify a group of patients a t increased risk.