Clinical features and prognosis of idiopathic inflammatory myopathy complicated by heart failure with preserved ejection fraction

OBJECTIVES: Idiopathic inflammatory myopathy (IIM) is increasingly recognized as a systemic disorder with frequent subclinical myocardial involvement. However, its coexistence with heart failure with preserved ejection fraction (HFpEF) remains poorly understood. This study aimed to comprehensively characterize the clinical, serological and radiological features of IIM patients with HFpEF and assess the prognostic utility of the HFA-PEFF score in this setting. METHODS: In this cohort study, 134 patients with IIM were stratified into low-, intermediate- and high-risk categories according to their HFA-PEFF score. Clinical characteristics and long-term outcomes were compared across groups. RESULTS: Of the 134 patients, 22 (16.4%) were classified as high risk (HFA-PEFF ≥5). This group was significantly older and exhibited lower free triiodothyronine levels, higher CRP and cardiac troponin T levels (all P < 0.05), and a greater prevalence of interstitial lung disease with advanced pulmonary fibrosis. Late gadolinium enhancement on cardiac MRI was observed in 78.5% of high-risk patients. The high-risk group also had significantly higher positivity rates for ANA, anti-SSA, anti-Jo-1, and anti-Ro52 antibodies (P < 0.05), implicating a possible link between autoimmunity and myocardial remodelling. Kaplan-Meier analysis revealed a markedly reduced 5-year survival in the high-risk group (47.1%) compared with the low- and intermediate-risk groups (88.7% and 84.5%, respectively; P < 0.001). In multivariable Cox regression, an HFA-PEFF score ≥5 remained an independent predictor of all-cause mortality (HR 3.124, P < 0.05). CONCLUSION: Our findings underscore the prognostic relevance of specific autoantibodies and cardiac fibrosis in IIM. Incorporating HFA-PEFF-based risk stratification into clinical practice may enable earlier interventions and personalized monitoring for high-risk patients.