A COMPARATIVE STUDY OF AMBULATORY BLOOD PRESSURE LEVELS, TRAJECTORIES AND SHORT-TERM BLOOD PRESSURE VARIABILITY IN DIABETIC AND NON-DIABETIC PATIENTS WITH CKD STAGE 2, 3A, 3B AND 4

Abstract

Objective: Diabetic kidney disease is the leading cause of end-stage renal disease worldwide. Whether diabetes mellitus (DM) is an additional factor leading to elevated blood pressure (BP) levels and BP variability (BPV) in patients with chronic kidney disease (CKD) is unknown. This study aimed to compare ambulatory BP levels, BP trends and BPV in diabetic and non-diabetic patients with CKD. Design and method: This study included 48 diabetic and 48 non-diabetic adult patients (>18 years) with CKD (eGFR: < 90 and >15 mL/min/1.73m2), matched in a 1:1 ratio for age, sex and eGFR within each CKD stage (2, 3a, 3b and 4). All patients underwent 24-hour ambulatory BP measurement with the Mobil-O-Graph device. To evaluate the effect of diabetes and time on the trajectories of 24-hour BP levels, we performed two-way mixed ANOVA analysis for repeated measurements using hourly means. BPV was calculated using standard deviation (SD), weighted SD (wSD), coefficient of variation (CV) and average real variability (ARV) of BP during the 24-hour, day- and night-time periods. Results: In total, patients with DM had significantly higher 24-hour systolic BP (SBP) (132.13 ± 10.71 vs 124.16 ± 11.45 mmHg, p = 0.001) and similar 24-hour diastolic BP (DBP) (75.00 ± 8.43 vs 74.62 ± 6.86 mmHg, p = 0.809) compared to patients without DM. A similar trend was evident across all CKD stages. The effect of DM on BP trajectories during the recording period was significant for SBP [F = 18.766, p < 0.001, partial h2 = 0.261] and marginally significant for DBP [F = 3.782, p = 0.057, partial h2 = 0.067]. 24hour SBP SD, wSD and ARV (10.94 ± 2.75 vs 9.46 ± 2.10, p = 0.004), as well as 24hour DBP SD, wSD, CV and ARV (8.23 ± 2.10 vs 7.10 ± 1.32, p = 0.002) were significantly higher in diabetic compared to non-diabetic CKD patients. Conclusions: Ambulatory SBP levels are higher and SBP-profile is different in patients with diabetic compared to those with non-diabetic CKD. Systolic and diastolic BPV are also higher in diabetic subjects. These findings may signify a higher cardiovascular risk of diabetic CKD patients.