Studies conducted in developed countries have found measurements of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) to be important in evaluating heart failure (HF) prognosis, however this has not yet been studied in sub-Saharan Africa. The aim of this study was to determine clinical correlates and short-term prognostic value of plasma NT-proBNP levels among HF patients.
This was a hospital-based prospective cohort study conducted at Jakaya Kikwete Cardiac Institute, Tanzania from June to December 2020. Patients were consecutively enrolled when they fulfilled the inclusion criteria. Clinical details and NT-proBNP levels were measured at baseline and at 30-day follow-up. Pearson's chi square test was used to associate New York Heart Association (NYHA) functional class and NT-proBNP levels, while Spearman’s correlation coefficient was used to correlate between left ventricular ejection fraction (LVEF) and NT-proBNP levels. Receiver Operating Characteristic (ROC) curves were drawn to determine the best prognostic cut off points of NT-proBNP levels for the different clinical outcomes. A P-value of <0.05 was considered statically significant.
155 HF patients were enrolled. Their mean±SD age was 48±16 years, 52.3% were male and their mean ±SD LVEF was 37.3±10.7%. At baseline, the median (IQR) NT-proBNP levels was 7654pg/ml (2289, 16000), and the levels dropped to 3383pg/ml (731, 9785) after 1 month. Baseline plasma levels of NT-proBNP increased as the NYHA functional class worsened, (P = 0.018), and with decreasing LVEF (r = -0.65, p<0.05). The ROC curve identified an overall cut-off point for poor prognosis at 18000pg/ml with 54.4% sensitivity and 93.7% specificity (area under the curve (AUC): 0.8). The NT-proBNP cut-off point for mortality was 24500 pg/ml with 100% sensitivity and specificity of 92.54% (AUC: 0.958). The ROC analysis also identified levels of NT-proBNP of ≥7899pg/ml to predict re-hospitalization, with 76% sensitivity and 60% specificity (AUC: 0.68), while levels ≥18762.1 pg/ml predicted long hospital stay with a sensitivity of 100% and specificity of 85.62% (AUC: 0.939).
These results demonstrate that NT-proBNP is a powerful measure to predict readmission, mortality and long hospital stay in HF patients and can facilitate discussions with patient prognosis, decisions regarding interventions, and continuity of care.