Effect of low glomerular filtration rate on evaluating the cardiac function by N-terminal pro-brain natriuretic peptide in patients with hypertension

Objective: To assess the diagnostic accuracy of NT-proBNP in hypertension patients by observing the effect of decreased GFR on N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration in patients with different cardiac function. Methods: Eighty-nine hypertension patients were divided into two groups based on the results of UCG. Forty-three patients had normal left ventricular function and 46 patients had dysfunction. GFR, NT-proBNP and other biochemical markers of cardiac and renal function were measured. The factors affecting the NT-proBNP concentration under normal left ventricular function were analyzed, and the diagnostic value of NT-proBNP affected by normal or decreased GFR (> 80 ml/min or ≤80 ml/min) under different left ventricular functions were further assessed. The two-sample t test, rank sum test and multiple regression analysis were used to analyze their statistical difference and relationship. Results: In patients with normal left ventricular function, GFR (β=-0.361, P<0.05) and left ventricular end-diastolic diameter (LVEDD, β=0.385, P<0.05) were significant factors to NT-proBNP level. They were both meaningful compared with LVEF (β=0.189, P>0.05) and septal thickness (β=0.003, P>0.05). The median concentration of NT-proBNP was 13.18 and 24.14 μg/L in patients with normal left ventricular function and dysfunction, respectively (Z=-3.19, P<0.01). While in patients with decreased GFR, 6 cases with normal left ventricular function and 19 cases with dysfunction had a median concentration of NT-proBNP of 38.45 and 44.20 μg/L, respectively (Z=-0.45, P>0.05). In patients with normal GFR, 37 cases with normal left ventricular function and 27 cases with dysfunction had a median concentration of NT-proBNP of 12.51 and 20.31 μg/L, which was lower than that of patients with decreased GFR (Z=-2.76, both P<0.05). The NT-proBNP concentration had no significant difference between patients of normal left ventricular function with decreased GFR and patients of dysfunction with normal GFR (38.45 and 20.31 μg/L, Z=-2.18, P>0.05). Conclusion: In hypertension patients, the effect of decreased GFR on assessing the diagnostic accuracy of NT-proBNP for left ventricular dysfunction should be considered. (authors)