White coat hypertension and masked hypertension among omani patients attending a tertiary hospital for ambulatory blood pressure monitoring.

OBJECTIVES Our study aimed to estimate the rate of white coat hypertension (WCH) and effect, and masked hypertension in patients attending a tertiary care hospital for 24 hour ambulatory blood pressure monitoring (24-h ABPM). METHODS A total of 231 adult patients were referred to the Department of Clinical Physiology at Sultan Qaboos University Hospital, Muscat, for ABPM, between January 2010 and June 2012. The following data were gathered and analyzed: demographic data, clinic blood pressure (BP) measurements, and 24-h BP profile from ABPM. Thirty-two patients were excluded and the final analysis included 199 patients. RESULTS There were 105 (52.8%) women and 94 (47.2%) men studied. The mean age of patients was 46±15 years and most patients were overweight with a mean BMI of 29.6±5kg/m(2). Around half of patients (53.8%) were on one or more antihypertensive medications. WCH was found in 10.6% and white coat effect was found in 16% of patients. The majority of patients (57%) with WCH were aged 40 years or above. Masked hypertension was present in 6% of patients and masked uncontrolled hypertension in 8.5% of patients. CONCLUSIONS Our study showed that WCH and effect, and masked hypertension are common in hypertensive patients. Identifying these patients will have an impact on their management. However, the results of the study should be interpreted within the context of its limitations. Prospective randomized community and hospital-based studies should be conducted to estimate the true prevalence in the general population as well as in hypertensive patients.