Validation of the Get With The Guideline-Heart Failure risk score in Japanese patients and the potential improvement of its discrimination ability by the inclusion of B-type natriuretic peptide level

Background Detailed characteristics of patients with acute heart failure (AHF) in Japan have not been elucidated. Furthermore, international application of risk models obtained in the United States has not been validated. Methods We evaluated the Get With The Guidelines-Heart Failure (GWTG-HF) risk score performance in AHF patients enrolled in the West Tokyo Heart Failure registry, a large, ongoing, prospective, multicenter cohort registry. Variables required for the GWTG-HF risk score were race, age, systolic blood pressure, heart rate, blood urea nitrogen level, sodium concentration, and presence of chronic obstructive pulmonary disease. Score discrimination and calibration were evaluated by the c statistic, Hosmer-Lemeshow statistic, and visual plotting. We conducted additional analyses to determine whether other variables improved the performance of the score. The primary outcome was in-hospital mortality. Results In total, 1,876 patients were admitted for AHF between April 2006 and August 2014. The patients were predominantly men (60.6%), with a mean age of 73.3 ± 13.6 years. Sixty-eight (3.6%) patients died during hospitalization. The GWTG-HF risk score showed acceptable discrimination; the c statistic for in-hospital mortality in this cohort was 0.763 (95% CI, 0.700-0.826). The calibration plot showed good conformance between the predicted and observed in-hospital mortality. Notably, addition of B-type natriuretic peptide level to the conventional GWTG-HF score significantly improved the discrimination (c statistic, 0.818; 95% CI, 0.771-0.865). Conclusions The GWTG-HF risk score can be applied in Japanese AHF patients with good discrimination and calibration. Furthermore, addition of B-type natriuretic peptide level improves discrimination and could be considered in future risk models.