Heart failure mortality according to acute variations in N-terminal pro B-type natriuretic peptide and cystatin C levels

AIM: Changes in N-terminal pro B-type natriuretic peptide (NT-proBNP) levels and cystatin C (CysC) are predictors of adverse outcomes in acute heart failure. This study assess whether NT-proBNP variations might provide independent information in addition to that obtained from CysC levels. METHODS: NT-proBNP levels were assessed in patients admitted due to acute heart failure using an observational study. Patients were classified as follows: group 1, those with a decrease in NT-proBNP levels of at least 30% from admission to 4 weeks after discharge; group 2, those with no significant changes in levels; and group 3, those who showed an increase in NT-proBNP of 30%. A multivariable Cox regression model and c-statistics were used. The primary end-point was all-cause mortality at 1-year follow-up. RESULTS: A total of 195 patients completed the follow-up. The mortality rate reached 20.5% (40 patients); 14 out of the 32 in group 3. The cumulative incidence of death, according to the change in NT-proBNP and Kaplan-Meier analysis, showed a significant increase in group 3 (log-rank P = 0.004). In the multivariable analysis, NT-proBNP variation for group 3 (hazard ratio 4.27; P <0.001) and for group 2 (hazard ratio 2.19; P = 0.043) in comparison with group 1 were independently associated with all-cause mortality, as well as anemia, hyponatremia, and admission CysC levels. Patients in group 3, and those with levels of serum CysC above the median, were also associated with slight increase in mortality. CONCLUSION: An increase of at least 30% in NT-proBNP levels after hospitalization is related to all-cause mortality in patients with acute heart failure and provides supplementary prognostic information in patients with high levels of CysC. A decrease in NT-proBNP of at least 30% is a desirable target to achieve.