Prognostic values of NTpro BNP/BNP ratio in comparison with NTpro BNP or BNP alone in elderly patients with chronic heart failure in a 2-year follow up

BackgroundPlasma BNP and NT-proBNP are often used as interchangeable parameters in heart failure care in clinical practice. In our previous study we have shown that inflammation was able to induce increased NT pro BNP in a hospital cohort with chronic heart failure in the elderly, indicating that NT-proBNP/BNP ratio should be evaluated concomitantly with inflammatory status to avoid overestimation of heart failure severity. The present study was aimed to evaluate the clinical significance of NT-proBNP/BNP ratio in comparison with NTpro BNP or BNP alone as a prognostic indicator in a 2-year follow up of elderly heart failure population.Materials and methodsOne hundred and eight-nine elderly heart failure patients (72 ± 11 years, male 52%, LVEF 46 ± 14%) were enrolled consecutively during 2006 and 2007 and followed up during 2 years. NTpro BNP and BNP were measured routinely.ResultsWe have found that NTpro BNP/BNP ratio provides no additional prognostic information during follow up as compared to NTpro BNP or BNP alone in an elderly population with chronic heart failure. By the use of ROC curves, for total mortality predictive accuracy during 2 years, the cut-off values are NTproBNP ≥ 800 pg/ml, BNP > 60 pg/ml and NTpro BNP/BNP ratio > 6.4 respectively. In terms of NTpro BNP, as long as its serum level is above 2000 pg/ml it indicates poor prognosis. However there is an overlap between serum concentration range 2000–8000 pg/ml and > 8000 pg/ml in terms of prognostic indicator. Similarly for BNP, as long as its serum level is above 100 pg/ml, it indicates poor prognosis. However there is an overlap between serum concentration range 100–800 pg/ml and > 800 pg/ml in terms of prognostic indicator. There was significant correlation between survival and NTpro BNP, BNP and Cystatin-C but not with NTpro BNP/BNP ratio. Such correlation exists irrespective of subgroups regardless of less than or older than 70 years old.ConclusionsOur results demonstrated that in elderly heart failure population NTpro BNP/BNP ratio may provide diagnostic help in the presence of acute infection but no additional prognostic information in the long run as compared with NTpro BNP or BNP alone. Furthermore, both NTpro BNP and BNP are useful prognostic biomarkers indeed but they need to be interpreted with caution when it is used as a single biomarker and in the meantime concomitant diseases exist because patients may die due to non-cardiac causes.