Features of erythrocyte membranes beta-adrenoreactivity in patients with resistant hypertension and type 2 diabetes mellitus

Introduction. Patients with resistant hypertension (RHTN) and type 2 diabetes mellitus (T2DM) are characterized by sympathetic hyperactivity. A promising method for the assessment is a measurement of erythrocyte membrane beta-adrenergic reactivity (β-ARM). However, little is known about β-ARM in patients with RHTN and T2DM.Purpose. To investigate the properties of β-ARM of erythrocytes in patients with RHTN and T2DM in relation to clinical, laboratory, and instrumental data.Material and Methods. The cross-sectional study comprised 38 patients with RHTN combined with T2DM with mean age of 62.1 ± 7 years (25 women (65.8%)), 24-hour systolic/diastolic blood pressure (24-BP) (SBP/DBP) of 160.3 ± 14.2/90.8 ± 10.5 mm Hg, and glycated hemoglobin (HbA1c) of 7.2 ± 1.4%. The comparison group comprised 24 patients with RHTN without T2DM, which did not significantly differ in sex and age. General clinical examinations, measurements 24-BP and office blood pressure, β-ARM, HbA1c, 24-hour urine, echocardiography, and 24-hour electrocardiography with the assessment of heart rate variability (HRV) with low-frequency (LF) and high-frequency (HF) components were performed in all patients.Research Results. In both groups, β-ARM was significantly higher than the normal value corresponding to 20 conventional units (CU): 45.9 ± 21.9 and 41.3 ± 18.9 for patients with RHTN+T2DM and RHTN without T2DM, respectively, p = 0.39. The incidence of increase in β-ARM was comparable: 82% in RHTN with T2DM patients and 88% in RHTN without T2DM patients, χ2 = 0.38, p = 0.537. The β-ARM values correlated with duration of hypertension (R = 0.31), SBP-24 variability (R = 0.36), LF (R = 0.60), and HF (R = -0.53)) values according to HRV, 24-hour urine volume (R = -0.32), left ventricular parameters (ejection fraction (R = 0.42), ventricular efficiency (R = -0.36), arterioventricular coupling (R = -0.40)), duration of T2DM (R = -0.45), and HbA1c level (R = -0.55).Conclusions. RHTN patients were characterized by a high frequency of β-ARM increase, whether or not T2DM was present, although a long and severe course of T2DM was associated with lower values of this indicator. According to the data from instrumental studies, β-ARM in patients with RHTN and T2DM was quantitatively related to the markers of sympathetic activity, which correlated with the duration of hypertension and parameters of renal and left ventricular functional status.