Prevalence of White Coat Effect in Patients with Pseudo-resistant Hypertension

Introduction: The prevalence of white coat effect (WCE) in patients with pseudo-resistant hypertension is not established locally. WCE may result in unwarranted intensification of therapy, leading to increased health costs, drug adverse effects, and decreased adherence to prescribed treatment. Therefore, the primary objective is to determine the prevalence of WCE and their clinical characteristics among patients with pseudo-resistant hypertension in Malaysia. Methodology: Patients suspected of pseudo-resistant hypertension on at least 3 anti-hypertensive drugs were recruited. Office blood pressure (BP) were repeated before being reassessed with a 24-hour ambulatory blood pressure monitoring (ABPM). Patients with an elevated office BP of >20/10 mmHg in contradictory to 24-hour BP of <130/80 mmHg were formally diagnosed as controlled hypertension with white coat effect. Results: Of the 430 patients screened, 413 with valid ABPM were analysed. Of which, 224 had controlled hypertension. Of which, 133 (59.4%) had WCE. Their mean age was 54.38  8.1, predominantly female (70.7%), Malay (39.8%) with underlying type 2 diabetes mellitus (75.9%), dyslipidaemia (88.7%), chronic kidney disease (20.3%) and Body Mass Index (BMI) of 30.8  5.6. Echocardiogram showed 34.8% with concentric left ventricular hypertrophy (LVH). Baseline office BP was 146.7  14.3/ 78.1  10.8 mmHg. In contrast, 24-hour BP was 115.0  7.5/ 69.7  5.7 mmHg, and the majority were non-dippers (62.4%). 97.7% were compliant to medication while taking 3.9  0.8 number of anti-hypertensive medications. Discussion/conclusion: WCE is prevalent in patients with pseudo-resistant hypertension (32.2%), similar to studies published on other populations. Therefore, identifying WCE in pseudo-resistant hypertension is important to prevent over-treatment. Hence, 24-hour ABPM is recommended to ascertain WCE and guide further management.