Clinical characteristics of primary biliary cirrhosis - idiopathic inflammatory myopathy overlap syndrome: A single center study.

Purpose: Primary biliary cirrhosis-idiopathic inflammatory myopathy (PBC-IIM) overlap syndrome (OS) is a rare condition in which cardiac involvement is observed. We aimed to characterize the clinical features and associated factors of PBC-IIM OS patients with cardiac involvement.

Methods: Patients with PBC-IIM OS that visited our hospital from January 1983 to December 2021 were enrolled. Clinical presentations and laboratory and imaging data were recorded. The clinical data of patients with and without cardiac involvement were compared. According to the first instance of a disease flare, prognostic factors were also studied.

Results: Thirty-four patients with PBC-IIM OS were enrolled. A total of 58.8% of patients presented with muscle weakness at disease onset, which primarily involved skeletal muscle (85.3%). Slight liver dysfunction was discovered in this OS cohort. In patients with cardiac involvement, palpitation (63.6%) and dyspnea (36.4%) were the most common onset symptoms. Arrhythmia was a vital manifestation in OS patients, in which half of OS patients had nonsustained ventricular tachycardia (50.0%, 11/22). Compared with noncardiac involvement, myalgia (4.5%, P = 0.004) and fever (0.0%, P = 0.011) were reported relatively rarely at disease onset in the group with cardiac involvement. The prognosis analysis showed that positivity for anti-Ro52 (HR=0.00, P = 0.034) negatively correlated with relapse in OS patients.

Conclusion: PBC-IIM OS has unique features. Typical clinical manifestations and early worsening cardiac indicators can be used to identify cardiac involvement and predict prognosis. Anti-Ro52 may have prognostic value for PBC-IIM OS.