Risk Prediction in Transition: MAGGIC Score Performance at Discharge and Incremental Utility of Natriuretic Peptides.

Abstract

BACKGROUND\nRisk stratification for hospitalized heart failure (HF) patients remains a critical need. The Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) score is a robust model derived from ambulatory HF patients. Its validity at the time of discharge and the incremental value of natriuretic-peptides (NP) in this setting is unclear.\n\n\nMETHODS\nThis was a single center study examining a total of 4138 HF patients from 2 groups; hospital discharge patients from administrative data (n\u202f=\u202f2503, 60.5%) and a prospective registry of ambulatory HF patients (n\u202f=\u202f1635, 39.5%). The ambulatory registry patients underwent NTproBNP measurement at enrollment, and in the hospitalize discharge cohort clinical BNP levels were abstracted. The primary endpoint was all-cause mortality within 1 year. MAGGIC score performance was compared between cohorts utilizing Cox regression and calibration plots. The incremental value of NPs was assessed using calculated area under the curve and net reclassification improvement (NRI).\n\n\nRESULTS\nThe hospitalized and ambulatory cohorts differed with respect to primary outcome (777 and 100 deaths respectively), sex (52.1% v 41.7% female) and race (35% v 49.5% African American). The MAGGIC-score showed poor discrimination of mortality risk in the hospital discharge (C-statistic 0.668, HR 1.1 per point, 95% CI 0.652, 0.684) but fair discrimination in the ambulatory cohorts (C-statistic 0.784, HR 1.16 per point, 95% CI 0.74, 0.83), respectively, a difference that was statistically significant (p\u202f=\u202f0.001 for C-statistic, 0.002 for HR). Calibration assessment indicated that the slope and intercept (of MAGGIC-predicted to observed mortality) did not statistically differ from ideal in either cohort and did not differ between the cohorts (all p>0.1). NP levels did not significantly improve prediction in the hospitalized cohort (p\u202f=\u202f0.127) but did in the ambulatory cohort (C-statistic 0.784 (95% CI 0.74, 0.83) vs. 0.82 (95% CI 0.78, 0.85); p\u202f=\u202f0.018) with a favorable NRI of 0.354 (95% CI 0.202-0.469; p=0.002).\n\n\nCONCLUSION\nThe MAGGIC score showed poor discrimination when used in HF patients at hospital discharge, which was inferior to its performance in ambulatory HF patients. Discrimination within the hospital discharge group was not improved by including hospital NP levels.