Heart failure and anemia: Effects on prognostic variables

Abstract

Background: Anemia is frequent in heart failure (HF), and it is associated with higher mortality. The predictive power of established HF prognostic parameters in anemic HF patients is unknown.

Methods: Clinical, laboratory, echocardiographic and cardiopulmonary-exercise-test (CPET) data were analyzed in 3913 HF patients grouped according to hemoglobin (Hb) values. 248 (6%), 857 (22%), 2160 (55%) and 648 (17%) patients had very low (<11g/dL), low (11-12 for females, 11-13 for males), normal (12-15 for females, 13-15 for males) and high (>15) Hb, respectively.

Results: Median follow-up was 1363days (606-1883). CPETs were always performed safely. Hb was related to prognosis (Hazard ratio (HR)=0.864). No prognostic difference was observed between normal and high Hb groups. Peak oxygen consumption (VO₂), ventilatory efficiency (VE/VCO₂ slope), plasma sodium concentration, ejection fraction (LVEF), kidney function and Hb were independently related to prognosis in the entire population. Considering Hb groups separately, peakVO₂ (very low Hb HR=0.549, low Hb HR=0.613, normal Hb HR=0.618, high Hb HR=0.542) and LVEF (very low Hb HR=0.49, low Hb HR=0.692, normal Hb HR=0.697, high Hb HR=0.694) maintained their prognostic roles. High VE/VCO₂ slope was associated with poor prognosis only in patients with low and normal Hb.

Conclusions: Anemic HF patients have a worse prognosis, but CPET can be safely performed. PeakVO₂ and LVEF, but not VE/VCO₂ slope, maintain their prognostic power also in HF patients with Hb<11g/dL, suggesting CPET use and a multiparametric approach in HF patients with low Hb. However, the prognostic effect of an anemia-oriented follow-up is unknown.

Keywords: Anemia; Heart failure; Prognosis.