Incorporating hypochloremia provides additive prognostic information in hospitalized patients with heart failure

Abstract

Abstract Background Although hypochloremia has been suggested as a strong marker of mortality in hospitalized patients with heart failure (HF), it has not been clarified whether incorporating hypochloremia into pre-existing prognostic model improves the model performance to predict long-term mortality in patients with chronic heart failure. Purpose The aim of this study is to develop a novel risk model which adds hypochloremia as a component into the pre-existing risk model and identify whether the model performance has improved its performance or not. Methods We calculated the pre-existing modified Get-With-the-Guideline®risk score(GWTG-RS) which is composed of GWTG risk score + anemia + NYHA + log-BNP, and also developed a new risk score adding hypochloremia into the modified GWTG-RS in patients enrolled in REALITY-AHF or NARA-HF. Hypochloremia was defined as < 97 mmol/L. The validation and comparison of the model performance were performed in two large scale heart failure cohorts. All models were tested for one-year mortality. Results We tested the prognostic value of hypochloremia measured at the time of discharge in 2,496 hospitalized patients with HF registered to REALITY-AHF or NARA-HF. Patients with hypochloremia were strongly associated with one-year mortality compared to those without (Log-rank: p<0.001), and this association was retained even after adjustment for GWTG-RS variables, anemia, NYHA and log-BNP (HR 1.64; p<0.001). Next, we tested whether adding hypochloremia to the prediction model comprised of the modified GWTG-RS improves its performance, and it yields numerically larger area under the curve (0.740 vs. 0.749; p = 0.059) and significant improvement in net-reclassification (0.159; p = 0.010). Conclusions Presence or absence of hypochloremia at discharge provides incremental prognostic information on top of pre-existing risk prediction model in hospitalized patients with HF.Kaplan-Meier curves for 1-year survival