Hydroxychloroquine for recurrent pericarditis: A multicentre observational study

AIM: To assess the effect of hydroxychloroquine (HCQ) in recurrent pericarditis (RP). METHODS: International longitudinal observational study including 80 patients with idiopathic or post-cardiac injury RP, treated with HCQ for at least 6 months (April 2014-August 2025); 3 other patients stopped HCQ within 6 months for side-effects. Recurrences, hospitalizations, side effects and therapies were evaluated before and after HCQ. Patient and physician-reported effectiveness were recorded. RESULTS: Females were 57/80 (71 %); median age 51.5 years [IQR 43.8-62.8]. C-reactive protein (CRP) was >10mg/L in 52 (65 %) patients. The median follow-up after starting HCQ was 27.3 [11.7-47.8] months, and the daily dose was 400 mg in 52 patients (65 %) and 200 mg in 28 (35 %). Among the 62 patients treated with HCQ for at least 12 months, recurrences decreased in the 12 months following treatment (median 1 [0-2]) compared with the 12 months preceding it (median 2 [1-3])(p < 0.001), as well as hospitalizations (5 vs 32) (p < 0.001). HCQ was effective either in CRP positive or CRP negative subjects. Fifty-four patients (67.5 %) were on steroids when HCQ was started, but only 21 (26.3 %) continued them at the last follow-up (p < 0.001); the median daily dose of prednisone was reduced from 10.0 mg [7.5-17.5] to 5.0 [2.5-5.0] (p < 0.001). Regarding patients' opinions about HCQ effectiveness, 64 pts (80 %) judged it useful, 16 (20 %) neutral (8 stopped HCQ for lack of effectiveness); the physicians' opinions were similar (concordance rate 74 (93.7 %), k 0.777; p < 0.001). CONCLUSIONS: HCQ reduced recurrences, hospitalizations, and corticosteroid dose in RP, with no relevant side effects.