Elucidation of predictors of disease progression in patients with relapsing polychondritis at the onset: potential impact on patient monitoring

BACKGROUND: In patients with relapsing polychondritis (RP), organ involvement developed in those with progressive and/or long disease courses. For their management, elucidation of a subgroup suggesting disease progression is awaited. METHODS: We previously conducted a physician’s questionnaire-based retrospective study to elucidate major clinical features of Japanese patients with RP. We here evaluated organ involvement at disease onset and at the last follow-up. We then counted cumulative numbers of involved organs at the last follow-up in 229 RP patients and compared them with involved organ numbers at disease onset, as possible indicators of disease progression. We assigned their prognosis at the last follow-up into “patient prognostic stages” from no medication (stage 1) to death (stage 5). We utilized nonparametric tests for group comparisons. RESULTS: Involved organ numbers per-patient were 1.13 ± 0.03 at disease onset and 3.25 ± 0.10 at the last follow-up (disease duration was 4.69 ± 0.33 years), and increased along with the patient prognostic stages. At disease onset, 135 and 48 patients had auricular involvement (59% of 229 patients, defined as auricular-onset subgroup; AO) and respiratory involvement (21%, respiratory-onset subgroup; RO), respectively. 46 patients presented with other conditions (20%, miscellaneous-onset subgroup; MO) including CNS, ocular, and inner ear involvement, among others. RO patients showed worse (poorer) prognostic stages than AO patients. MO patients developed respiratory and/or auricular involvement thereafter and then showed significantly higher mortality rate (15%; 7/46) than AO patients (5.9%; 8/135). In RP patients who did not develop respiratory involvement until the last follow-up (throughout the disease course; 117 patients), mortality rate was 19% in 26 MO patients and 3.3% in 91 AO patients. Accordingly, RO patients and MO patients associated with relatively poor prognosis compared with AO patients. CONCLUSIONS: Allocation of patients to RO and MO subgroups was suggested to associate with poorer prognosis of RP than AO subgroups, especially AO subgroups without respiratory involvement throughout. All RP patients deserve careful monitoring but special attention should be paid to MO patients because of their diverse and accelerated disease progression.