White coat hypertension (WCHT) and white coat effect (WCE) are often thought to be of the same entity. They are in fact different conditions which carry distinctive definitions and prognostic significance. WCHT is diagnosed when office blood pressure (OBP) is ≥140/90 mmHg on at least 3 occasions, while the average daytime or 24-hour blood pressure is <135/85 mmHg. It is common with 15% prevalence in the general population and may account for over 30% of individuals in whom hypertension is diagnosed. Although individuals with WCHT were reported to have a better cardiovascular (CV) prognosis when compared to those with sustained hypertension and masked hypertension; they were also shown to have a greater prevalence of target organ damage (TOD) and metabolic abnormalities than that of normotensive subjects. In contrast, WCE is defined as the transient elevation of OBP induced by the alerting response to a doctor or a nurse. WCE can occur in both normotensive and hypertensive persons; and is not substantially influenced by reassurance and familiarisation. There is conflicting evidence with regards to prognostic significance of WCE, where most data indicated that it does not predict future TOD, CV morbidity or mortality; with some studies showed otherwise. This case scenario aims to solve the diagnostic perplexity with regards to WCHT and WCE, followed by an evidence-based commentary of how to best manage such conditions.
Hypertension is the leading cause of mortality worldwide. It is highly prevalent throughout the world. Even in regions liike South-East Asia (SEA) which has been perceived to be less prone to cardiovascular diseases, the prevalence of hypertension has been reported to be around 35% (1). Awareness and control of hypertension in SEA is also low, both being less than 50% each (2).Control of hypertension is an interplay between patients, doctors and system factors. One of the reasons for poor control of hypertension is resistant hypertension. Resistant hypertension is defined as blood presure that remains above goal despite being on three concurrent anti-hypertensive medications preferbaly one of which is a diuretic (3).True resistant hypertension should be differiented from secondary hypertension and pseudo-resistant hypertension. Resistant hypertension is almost always multi-factorial in aetiology. The exact prevalence of resistant hypertenion even in developed countries is not known It has been estimated that it is as high as 20-30% in clinical trial patients (4)Not many studies about resistant hypertension have been done in SEA but one done in an outpatient clinic in Thailand found it to be 7.82% Another study also done in a primary care clinc in Malaysia on 1217 patients with hypertension found the prevalence of resistant hypertension to be 8.8%. (6) Here it was found that the presence of chronic kidney disease was more likely to be associated with resistant hypertension (odds ratio [OR] 2.89, 95% confidence interval [CI] 1.56-5.35). Other factors like increasing age, female gender, presence of diabetes, obesity and left ventricular hypertrophyage which have been found to be predictors of resistant hypertension in other studies in the west were not seen in this study. There are various reasons for these findingsBut whatever the factors are that are associated with uncontrolled hypertension, the task is to sort out true resistant hypertension from pseudo-resistant hypertension and secondary casues of hypertension which may be treatable. A concerted effort is needed to reduce the BP in resistant hypertension. Failure to do so would mean a substantal increase in CV risk for the patient.