Association between glycated hemoglobin and ambulatory blood pressure or heart rate in hypertensive patients.

OBJECTIVES To determine the association between glycosylated hemoglobin (HbA1c) and ambulatory blood pressure or heart rate in hypertensive patients. METHODS A total of 585 patients, who performed ambulatory blood pressure monitoring (ABPM) from September 2018 to April 2019 in Xiangya Hospital, Central South University, were enrolled and assigned into 2 groups (470 in a hypertensive group and 115 in a normal group). HbA1c levels were compared. According to the HbA1c level, the hypertensive group was divided into 2 subgroups: A high HbA1c group (HbA1c≥6.1%, n=142) and a normal HbA1c group (HbA1c<6.1%, n=328). Whole basic data and ABPM parameter were compared among the groups. Pearson/Spearman correlation analysis was applied to study the association between HbA1c and BPV. Multivariate logistic regression was used to explore the influential factors for HbA1c (≥6.1%) and continuous increase of HbA1c in different hypertensive populations, respectively. RESULTS The hypertensive group had higher HbA1c level than the normal group [(6.1±1.3)% vs (5.1±1.7)%, P<0.05]. In hypertensive patients, nocturnal systolic blood pressure [(131.1±19.2) mmHg vs (122.5±19.2) mmHg], nocturnal systolic blood pressure load [62.5% (15.5%-100%) vs 28.6% (0-75%)], and daytime heart rate [(74.3±11.6) min-1 vs (71.2±11.4) min-1] of the high HbA1c group were higher than those in the normal HbA1c group (all P<0.05). Pearson/Spearman correlation analysis showed that HbA1c was positively correlated with systolic blood pressure and blood pressure load (both P<0.05). Logistic regression analysis showed that nocturnal systolic pressure load was the risk factor for the increase of HbA1c level (OR=1.025, 95% CI 1.003 to 1.048, P<0.05). Multiple linear regression showed that nocturnal systolic pressure load was still positively correlated with HbA1c in total, tertiary, and hypertensive patients without treatment (β=0.155, β=0.171, β=0.384, respectively, all P<0.05). CONCLUSIONS In hypertensive patients, HbA1c is positively correlated with ambulate blood pressure, blood pressure load, and heart rate, and it has no correlation with blood pressure variability, heart rate variability, or morning blood pressure.