Journal of Human (1999) 13, 801–802  1999 Stockton Press. All rights reserved 0950-9240/99 $15.00 http://www.stockton-press.co.uk/jhh COMMENTARY White coat hypertension: how should it be diagnosed?

E O’Brien Unit, Beaumont Hospital, Dublin 9, Ireland

Keywords: white coat hypertension; ABPM

White coat hypertension is a relatively new concept some may be at risk, albeit it considerably less so in clinical medicine, though the phenomenon has than patients with sustained hypertension. been recognized in various guises for many years.1 So far so good. Both observations are largely in The nomenclature has been questioned recently, agreement with a growing literature on these aspects and isolated clinic or office hypertension has been of white coat hypertension,5–7 but now reason proposed as a more fitting term.2 Reasonable though deserts the authors in their hour of need. Having this may be, the reality is that ‘white coat hyperten- made their case they go on to make two recommen- sion’ has, as the saying goes, ‘caught on’, both with dations with far-reaching implications: first, that the medical profession, and, more importantly, it subjects with white coat hypertension should have has become part of everyday parlance with our echocardiography, and, second, that they should patients in the hair salons, the pubs, and restaurants have their clinic blood pressure measured by the tra- where a fashionable diagnosis possessing a catchy ditional technique every 6 months. Both proposals diagnostic label capable of invoking sympathetic are seriously flawed, yet there are discernible, if conversation with the promise of enduring atten- unacceptable, influences at work. tion, but without unduly threatening its harbinger, Let us look firstly at the recommendation to per- is indispensable to after-dinner chatter. Let us agree form echocardiography in patients with white coat therefore to set this bogie aside, and accept the term, hypertension. In practice, this could mean per- white coat hypertension, whilst acknowledging its forming echocardiography in about 25% of all clinical imprecision. patients referred to a clinic expressing an interest in The importance of the condition rests on a curious hypertension. This recommendation might be haemodynamic phenomenon, which has quite pro- reasonable if echocardiography was an inexpensive found clinical relevance: patients—let us call them investigation with good reproducibility, but the people, because they may not be ill—who appear to reality is that it is more expensive than ABPM, is have hypertension when their blood pressure is dependent on observer acuity, is inaccessible to the measured by the traditional Riva-Rocci/Korotkoff majority of family physicians, and is unsatisfactory method, have normal blood pressures when ambu- in some 20% of subjects.8 latory techniques are used to record their blood Manning and her colleagues then go on to commit pressures away from the medical environment.3 a clinical oxymoron. Having shown with their data Manning and her colleagues make two obser- that the only way to diagnose white coat hyperten- vations on the condition in this issue of the Journal sion is by utilising ABPM, they then recommend 4 of Human Hypertension. First, white coat hyperten- that patients with white coat hypertension should sion (even allowing for differences of definition and be followed every 6 months by the practice nurse! referral bias) is common, but, of course not normal What will this achieve except to return the ‘patient’ (or we would all exhibit the phenomenon), being to the clutches of the original diagnostic genie, who present in about a quarter of their referral popu- if of similar mind or persona to the first, will, at best, lation. Second, white coat hypertension may not be ask for another ABPM, or if the gods are unkind, the altogether benign, as some 9% of their subjects had ‘subject’ now turned ‘patient’ will in all likelihood echocardiographic evidence of increased left ven- be subjected to life-long drug therapy? tricular hypertrophy. It would seem, therefore, that Yet the lack of logic in this approach is, as I have though most patients with white coat hypertension said, understandable. The authors anticipating the are not in need of antihypertensive medication, inevitable protest that will accompany the inescap- able conclusion deriving from their data (and that of others), that if we wish to diagnose white coat hypertension, ABPM is the best way of doing so, Correspondence: Eoin O’Brien have compromised, and in so doing have failed to White coat hypertension E O’Brien 802 face reality. Why then this fear to confront the evi- References dence with logical reasoning? The Luddites will 1 Ayman D, Goldshine AD. Blood pressure determi- shout from the turrets that the evidence is not to nation by patients with . Am J hand proving that ABPM is superior to conventional Med Sci 1940; 200: 465–474. measurement in predicting outcome (a nonsense as 2 Mancia G, Zanchetti A. White-coat hypertension: mis- the recent Syst-Eur data shows9), but diagnosing nomers, misconceptions and misunderstandings. What people with white coat hypertension is a clinical should we do next? J Hypertens 1998; 14: 1049–1052. rather than an epidemiological issue, and it should 3 Pickering TG et al. How common is white coat hyper- be seen as such and nothing more. We use ABPM to tension? JAMA 1988; 259: 225–228. 4 Manning G, Rushton L, Millar-Craig MW. Clinical find those people with elevated conventional blood implications of white coat hypertension: an ambulat- pressure, in whom blood pressure elevation is sus- ory blood pressure monitoring study. 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