Defining Clinical Subgroups in Relapsing Polychondritis: A Prospective Observational Cohort Study.

BACKGROUND/PURPOSE: Relapsing polychondritis (RP) is a systemic disease. Failure to recognize RP can lead to diagnostic delay and further complications including death. The study objective was to identify clinical patterns in a prospective cohort of patients with RP. METHODS: Patient subgroups were identified using latent class analysis by eight clinical variables: saddle nose deformity, subglottic stenosis (SGS), tracheomalacia (TM), bronchomalacia (BM), ear chondritis, tenosynovitis/synovitis, inflammatory eye disease, and audiovestibular disease. Model selection was based on Akaike Information Criterion. RESULTS: Seventy-three patients were included. Three subgroups were identified: Type 1 RP (14%); Type 2 RP (29%); and Type 3 RP (57%). Type 1 RP was characterized by ear chondritis (100%), TM (100%), saddle nose deformity (90%), and SGS (80%). These patients had the shortest time to diagnosis (median = 1 year), highest disease activity, and greatest frequency of ICU admissions and tracheostomy. Type 2 RP was characterized by TM (100%) and BM (52%), but without saddle nose deformity or SGS. These patients had the longest delay to diagnosis (median = 10 years) and highest percentage of work disability. Type 3 RP was characterized by tenosynovitis/synovitis (60%) and ear chondritis (55%). There were no significant differences in sex, ethnicity, and treatment strategies between the three subgroups. CONCLUSIONS: Three subgroups of patients with RP were identified that differ in time to diagnosis, clinical and radiological characteristics, and disease-related complications. Recognizing a broader spectrum of clinical patterns in RP, beyond just cartilaginous involvement of the ear and upper airway, may facilitate more timely diagnosis.