Usefulness of Incorporating Hypochloremia into the Get With The Guidelines–Heart Failure Risk Model in Patients With Acute Heart Failure

Although hypochloremia is strongly associated with adverse prognosis in acute heart failure (AHF), it is unknown whether incorporating hypochloremia into the preexisting risk model improves the model performance. We calculated the Get With The Guidelines-Heart Failure (GWTG-HF) risk score in 1,428 patients with AHF (derivation cohort) and developed 2 risk scores incorporating brain natriuretic peptide (BNP) into the GWTG-HF risk score (GWTG-BNP risk score) and incorporating both BNP and hypochloremia (GWTG-BNP-Cl risk score). Hypochloremia was defined as <98 mmol/L. The external validation and comparison of model performance were performed in an independent group of 1,256 patients with AHF (validation cohort). All models were tested for in-hospital mortality. Hypochloremia was observed in 9.4% and 12.2% of the derivation and validation cohorts, respectively. Hypochloremia was an independent predictor of in-hospital mortality in the derivation cohort (odds ratio 2.02; p = 0.028). In the validation cohort, the GWTG-HF, GWTG-BNP, and GWTG-BNP-Cl risk scores demonstrated good discrimination (area under the curve: 0.742, 0.749, and 0.763, respectively). However, the GWTG-BNP-Cl risk score was more reliable than the GWTG-HF and GWTG-BNP risk scores in risk reclassification (net reclassification improvement: 0.491 and 0.408, respectively; p <0.01 for both). Moreover, this score demonstrated a good calibration of the GWTG-BNP-Cl model (Hosmer-Lemeshow test: p = 0.479). In conclusion, incorporating hypochloremia into the preexisting risk model improves the model performance.