BACKGROUND: With the aging of the population, the number of patients with chronic heart failure (CHF) and comorbidities is increasing in Japan. Among the comorbidities, cardiorenal anemia syndrome (CRAS) is particularly important, but the age-specific prevalence and prognosis of CRAS remain unclear. METHODS AND RESULTS: The KUNIUMI registry chronic cohort is a prospective observational study of CHF (Stages B-D) in Awaji Island. In this study, we analyzed 1,646 patients registered in the KUNIUMI registry and categorized them into 4 groups: Group 1 included patients without cardiac failure (Stage B)
Group 2 consisted of patients with cardiac failure but without renal failure or anemia
Group 3 comprised patients with both cardiac failure and renal failure but without anemia
and Group 4 (CRAS) included patients with cardiac failure, renal failure, and anemia. The primary endpoint was composite of all-cause-death and heart failure hospitalization. The proportion of patients with CRAS increased with age. Furthermore, Group 4 showed a significantly worse prognosis than other groups (log-rank P<
0.01). On Cox proportional hazard regression analysis, compared with patients without cardiac failure, renal failure, or anemia, the age- and sex-adjusted hazard ratio for the primary endpoint in those with CRAS was 8.94 (95% confidence interval: 5.36-14.92). CONCLUSIONS: The prevalence of CRAS in CHF increases with age, and the prognosis associated with CRAS is generally worse compared with other comorbidities.