Correlations between B type natriuretic peptide and blood pressure in patients with type 2 diabetes mellitus

Abstract

Brain natriuretic peptide (BNP) plays key roles in regulating blood pressure, fluid and electrolyte balance. The aim of our study was to assess correlations between serum BNP levels and blood pressure among patients with type 2 diabetes mellitus (T2DM). We conducted a cross-sectional study among patients with T2DM below the age of 65 years regardless of duration of diabetes and type of antidiabetic drugs. Detailed medical history, measurements of systolic (SBP), diastolic blood pressure (DBP) and serum BNP were recorded. Patients with BNP > 300 pg/mL were excluded. The included patients were divided into four groups according to BNP quartiles: Q1 < 9; Q2 between 9 and 11.9; Q3 between 11.9 and 32.2; Q4 ≥ 32.2 pg/mL. Analysis of group differences was performed using the non-parametric Kruskall-Wallis test for continuous variables. and chi 2 test for trend for categorical variables. The comparison of percentages on independent series was carried out by the Pearson's chi 2 test, and in the case of invalidity, the bilateral Fisher's exact test was used. We included 69 diabetics, mean age: 56.7 ± 6.9 years old, sex ratio (M/F): 1.5, average duration of diabetes of 10.6 ± 7.7 years and average HbA 1c : 9.2 ± 1.9%. The mean level of serum BNP was 27.8 ± 32 pg/mL. More than half (61%) of the patients were hypertensive. Serum BNP was significantly higher among hypertensive patients than non-hypertensive patients (35.6 ± 5.7 vs. 15.7 ± 17.6 μg/mL, P = 0.001). We did not observe statistically significant correlation between the BNP level on the one hand and the SBP and the DBP on the other hand. Fourth quartile patients were 6.9 times more likely to have high blood pressure (95% CI [1.4, 33.5]) than patients in the first three quartiles ( P = 0.008). Patients in the 2nd quartile had significantly higher SBP than patients of the other quartiles ( P = 0.049). The DBP was comparable between the four groups ( P = NS). The relationship between high blood pressure and BNP was not significant among diabetic patients of our study. But it appears that a BNP level ≥ 32.2 pg/mL was a significant predictor of high blood pressure.