Mean Corpuscular Haemoglobin Concentration and Outcomes in Heart Failure with Preserved Ejection Fraction

Aims This study aims to evaluate the prognostic value of mean corpuscular haemoglobin concentration (MCHC) on clinical outcomes in patients with heart failure with preserved ejection fraction (HFpEF). Methods and results We analysed HFpEF participants from the Americas in the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial with available baseline data (n = 1747). Patients were grouped into hypochromia or non-hypochromia group according to a MCHC cut-off level of 330 g/L. Cox proportional hazard model was used to explore the prognostic value of hypochromia on the long-term clinical outcomes (the primary endpoint [composite of cardiovascular mortality, HF hospitalization and aborted cardiac arrest], any-cause and HF hospitalization, all-cause and cardiovascular mortality). Patients were further stratified according to baseline estimated glomerular filtration rate (eGFR) to explore the impact of renal dysfunction on the prognostic value of hypochromia. Baseline hypochromia was prevalent (n = 662, 37.9%) and strongly associated with worse clinical outcomes. In patients with worse renal function (eGFR < 60 mL/min per 1.73 m2), hypochromia was independently associated with primary endpoint (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.23–1.98; P < 0.001), any-cause hospitalization (HR, 1.43; 95% CI, 1.20–1.71, P < 0.001) and HF hospitalization (HR, 1.40; 95% CI, 1.07–1.84; P = 0.015), whereas no significant association between hypochromia and these outcomes was found in patients with better renal function. Conclusions Among HFpEF patients, hypochromia (i.e. MCHC ≤ 330 g/L) is independently associated with adverse clinical outcomes, especially when in the presence of co-morbidity renal dysfunction.