Background Atrial functional mitral regurgitation (AFMR) frequently affects older patients with heart failure (HF), causing venous congestion and reduced forward cardiac output. This hemodynamic compromise may accelerate chronic kidney disease (CKD) and impair oxygen delivery, thereby exacerbating anemia. Cardio-renal anemia syndrome (CRAS) is a prognostic factor in HF, and specific hemodynamic disturbances in AFMR may amplify its consequences. In this study, we aimed to evaluate the impact of CRAS on cardiovascular outcomes in patients with AFMR.

Methods The Real-World Observational Study for Investigating the Prevalence and Therapeutic Options for Atrial Functional Mitral Regurgitation (REVEAL-AFMR) registry is a multicenter, retrospective, observational cohort that enrolled patients with moderate-to-severe AFMR in 2019. Patients were stratified into the CRAS and non-CRAS groups based on the simultaneous presence of HF, CKD, and anemia. The primary outcome was a composite of all-cause mortality and hospitalization for HF.

Results Among the 986 patients analyzed, 258 had CRAS. Over a median follow-up period of 1,040 days, 327 composite events occurred. Kaplan–Meier analysis demonstrated a higher incidence of composite cardiovascular outcomes in patients with CRAS than in those without CRAS, consistent across all severities of AFMR. In multivariate Cox proportional hazards regression analysis, CRAS was independently associated with cardiovascular events, along with older age, lower body mass index, and lower systolic blood pressure.

Conclusion CRAS is common in patients with AFMR and may be independently associated with an increased risk of future cardiovascular events. Assessment of CRAS may be helpful for risk stratification and management in this population.

The authors have declared no competing interest.

UMIN000046146

This study was partially supported by the Uehara Memorial Foundation and the Japanese Society for the Promotion of Science KAKENHI (grant number 22K20895).

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Institutional Review Board of Juntendo University and each participating institution, including Kobe City Medical Center General Hospital (approval number: kzh250408)

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The data that support the findings of this study are available from the corresponding author upon reasonable request.