Prevalence of White Coat Hypertension in Patients with Chronic Kidney Disease

Background: Achieving target blood pressure is important in retarding the progression of chronic kidney disease (CKD). Optimizing patient's hypertension solely based on clinic blood pressure could be harmful as it may be masked by white coat hypertension. Objectives: This study aimed at determining the prevalence of white coat hypertension (WCHT) in patients with CKD and correlating this with their target organ damage evidenced by left ventricular hypertrophy (LVH) and carotid intima media thickness (CIMT). Methods: A cross sectional study of 99 patients with CKD (stage 3 to 5 with eGFR Epi of < 60 mL/min/1.732) at a CKD clinic was conducted. Demographic data, routine blood investigations, and number of antihypertensive medication were recorded. Mean clinic blood pressure of the last 2 visits were taken followed by 24-hour ambulatory blood pressure monitoring (24-hour ABPM), electrocardiography, and carotid ultrasound measurement. Results: Ninety-nine patients (42 males and 57 females) with median age of 62 (55 to 69) years old and predominantly Malays ethnicity were recruited. The prevalence of WCHT was 34.3% (34 patients), and 65.7% (65 patients) had sustained hypertension (SHT). Median eGFRs were comparable in both groups (P = 0.479). Despite comparable mean clinic blood pressure (P = 0.85), the WCHT group had significantly lower mean average systolic, daytime, and night time blood pressure when compared with the SHT group (120.82 ± 8.24 vs. 153.20 ± 18.70), (124.50 ± 9.51 vs 155 ± 18.86) , (111.97 ± 20.07 vs 146.22 ± 21.17 ) and diastolic (66.36 ± 85.79 vs. 82.35 ± 12.17), (68.71 ± 10.94 vs 84.11.8) , (62.68 ± 7.78 vs. 79.28 ± 12.17) respectively (P < 0.05). The trend towards significance of LVH in the WCHT compared with the SHT group (52% vs.38% (P = 0.066)) and the SHT group had a significantly higher median CIMT 0.80 mm (0.70 - 0.90) as opposed to the 0.60 mm median of the WCHT group (0.60 to 0.70) (P < 0.05). Two-thirds of SHT were non dippers. Conclusions: White coat hypertension is prevalent in CKD. Patients with SHT had significant carotid intima thickening; LVH was detected more commonly in the WCHT group.