White Coat Hypertension: Not So Benign After All?

Irene Chung and Gregory YH Lip University Department of Medicine, City Hospital, Birmingham B18 7QH, England, UK

Journal of Human Hypertension (2003) 17, 807–809. doi:10.1038/sj.jhh.1001651

Keywords: white coat hypertension, prognosis, management

White coat hypertension (WCH) describes the ‘definite (or established) hypertension’ was made phenomenon in which blood pressures are elevated with great certainty. in the presence of a health professional measuring Indeed, too much certainty can be a dangerous the blood pressureFtraditionally described (but not thing. While WCH may not be exactly the same as exclusively!) in relation to the hospital/clinic doc- overt essential hypertension (with target organ tor, who is usually wearing a white coat. Since the damage, etc), such patients are not quite ‘normal’. introduction of 24 h ambulatory blood pressure Nonetheless, a number of studies have suggested monitoring (ABPM),1 the meaning of WCH has been that WCH did not share the same metabolic risk redefined, and one possible definition of WCH is an factors (for example, fasting and postload insulin abnormal clinic blood pressure but ‘normal’ ABPM. levels; glucose/insulin rate, etc), endothelial dys- The latter has also been defined in many ways, but function, or target organ damage, as that seen in the recent Seventh Joint National Committee (JNC sustained hypertension.1,8–10 For example, one study 7)2 suggested that the upper limits of ‘normal’ ABPM found that the intima-media thickness of the carotid to be 135/85 mmHg while patients are awake and artery was significantly increased with sustained 120/75 mmHg while they are asleep. In contrast, the hypertension, but not in WCH.10 The study by 1999 World Health Organization/International So- Verdecchia et al1 also reported that the prevalence ciety of Hypertension (WHO/ISH) guidelines3 sug- of left ventricular hypertrophy was rare when gest that a 24 h average of home blood pressure of ambulatory systolic BP o120 mmHg, approximately 120/80 mmHg as corresponding to clinic blood 6% when ambulatory BP o130 mmHg, and up to pressure of 140/90 mmHg. 10% when ambulatory BP reaches 140 mmHg.1 WCH was probably first described by Riva-Rocci WCH was also though to carry a better prognosis more than 100 years ago. The prevalence of WCH is than sustained hypertension. For example, in the quite variable, depending of the selection of the study by Celis et al11 of 326 patients with a median patient groups. For example, in 1988, Pickering et follow-up of 5.3 years, all major 22 cardiovascular al4 first reported the prevalence of WCH to be 21% events occurred in the sustained hypertensive of all hypertensives, and they were more likely to be group; antihypertensive treatment in WCH did not female. Other studies have suggested a prevalence of appear to be beneficial.11 Similarly, a study of 958 between 12 and 54%,5 being more common in the older Japanese patients with a mean follow-up of 42 elderly.6 WCH may also account for up to 25% of months reported that the incidence of stroke in cases labelled as ‘resistant hypertension’.7 Clearly, WCH is similar to that of normotensives and one- WCH is a common phenomenon. fourth the risk in sustained hypertensives.12 The The importance of WCH has been increasingly longest follow-up study of 9.1 years was that of recognised. For too long has WCH been regarded as a Khattar et al,13 which reported cardiovascular out- Cinderella condition, being the result of stern comes in 479 patients with WCH compared to those doctors (or nurses) in pristine starched white coats, with sustained mild hypertensionFand found that who alarmed or stressed patients and raised their patients with WCH were younger (44 vs 52 years blood pressure readings, and the diagnosis of old) and had a significant lower incidence of cardiovascular events. In contrast, many studies have suggested Correspondence: Professor GYH Lip that WCH was associated with significant end- E-mail: [email protected] organ damage,14–19 with evidence of significant White coat hypertension I Chung and GYH Lip 808 LVH, greater intimal-medial thickness and Is it cost effective to monitor WCH? As we know, plaque index17 and more albuminuria than the cost of poor blood pressure control is astronom- normotensives.18 For example, Strandberg et al20 ical. As high blood pressure is the most important reviewed 21 years prospective data of 536 business- risk factor for cardiovascular disease, it is calculated men with cardiovascular risk factors at baseline that by achieving the target of 140 mmHg, there and found that men with white coat effect would be a reduction of 28–44% in stroke and 20– of 430 mmHg had significantly higher mortality 35% in ischaemic heart disease depending on the than the normotensive men. Surprisingly, this study age. This would prevent approximately 21 400 also showed that the ‘white coat’ group carried a stroke deaths and 41 400 ischaemic heart disease worse prognosis than the persistently hypertensive deaths each yearFthese translate to approximately group. 42 800 strokes and 82 800 ischaemic heart diseases In the current issue of the Journal of Human saved, making a total of 125 600 events saved per Hypertension, the paper by Gustavsen et al21 adds to year in the UK.22 These numbersFor the lack of the debate that WCH should be regarded as a effort to do anything about itFmake depressing cardiovascular risk factor. This study was a follow- reading, even to the most cynical of clinical up study on 420 patients with grade I–II hyperten- pharmacologists. sion newly diagnosed by their general practitioner and 146 normal controlsFwhere 18.1% of the 420 hypertensives had WCH. With a mean duration of References follow-up of 10.2 years (one of the longest in the literature), first events were recorded in 18.4% of 1 Verdecchia P et al. Ambulatory pulse pressure: a the WCH group (compared to 16.3% in the estab- potent predictor of total cardiovascular risk in hyper- lished hypertension group. The other main finding tension. Hypertension 1998; 32: 983–988. of this study was an increased cardiovascular risk in 2 Joint National Committee on prevention detection, WCH compared to normotensive controls. The evaluation, and treatment of high blood pressure. The strengths of this paper are the long follow-up and Seventh Report of the Joint National Committee on prevention, detection, evaluation, and treatment of the availability of control groups. Indeed, 100% high blood pressure. JAMA 2003: 289: 2560–2572. follow-up was achievable due to the unique Danish 3 1999 World Health OrganisationFInternational So- citizens’ personal ID number. As the authors ciety Guidelines for the Management of Hypertension. admitted, the cholesterol profiles and blood glucose Guidelines Subcommittee. J Hypertens 1999; 17: 151– of these subjects were not known, although a few 183. studies previously did not show any difference 4 Pickering TG et al. How common is white coat between WCH and normotensives regarding these hypertension? JAMA 1988; 259: 225–228. measures. 5 Aquirre-Ramos R et al. White-coat hypertension and A rational assessment of the data available risk factors in recently diagnosed hypertensive pa- suggests that WCH probably carries a better prog- tients. Gac Med Mex 2002; 138: 319–324. 6 Amado P et al. Arterial hypertension difficult nosis than sustained hypertension, although such to control in the elderly patient. The significance patients are not entirely benign. Indeed, WCH of the ‘white coat effect’. Rev Port Cardiol 1999; 18: should perhaps be treated as a ‘prehypertensive 897–906. state’ (with apologies to JNC7). Indeed, Verdecchia 7 Brown MA, Buddle ML, Martin A. Is resistant et al1 reported that in their follow-up study, 37% of hypertension really resistant? Am J Hypertens 2001; subjects with WCH spontaneously evolved into 14: 1263–1269. cases of ambulatory hypertension, with accompany- 8 Marchesi E et al. Metabolic risk factors in white coat ing increases in left ventricular mass. Among those hypertensives. J H Hyperten 1994; 8: 475–479. with baseline daytime ABPo130/80 mmHg, few 9 Pierdomenico SD et al. Endothelial function in (20%) developed established hypertension. The sustained and white coat hypertension. Am J Hyper- tens 2002; 15: 946–952. higher the baseline ambulatory BP, the more likely 10 Amar J et al. Intima media thickness of the carotid they are to develop established hypertension. artery in the white coat and ambulatory hypertension. To manage WHC, it is important to make the Arch Mal Coeur Vaiss 1997; 90: 1075–1078. correct diagnosis first by 24 h ABPM, and assess 11 Celis H et al. Cardiovascular risk in white-coat and evidence of end-organ damage. It is also important sustained hypertensive patients. Blood Pressure 2002; to assess for associated cardiovascular risk factors, 11: 325–327. in a similar manner as assessing any hypertensive 12 Kario K et al. Silent and clinically overt stroke in older patient. Evidence suggests that in the presence of Japanese subjects with white-coat and sustained end-organ damage (for example, LVH by echocardio- hypertension. JACC 2001; 38: 238–245. graphy, microalbuminuria, etc), antihypertensive 13 Khattar RS, Senior R, Lahiri A. Cardiovascular out- come in white-coat versus sustained mild hyperten- medication should be initiated. Other cardiovascu- sion. Circulation 1998; 98: 1892–1897. lar risk factors should also be corrected. If a 14 Hernaandez RR et al. Frequency of white coat diagnosis of WCH is made, blood pressure should hypertension in mild hypertension. Profile of cardio- still be regularly monitored, as over a third will later vascular risk and early organic involvement. Med Clin develop established hypertension. 1996; 106: 690–694.

Journal of Human Hypertension White coat hypertension I Chung and GYH Lip 809 15 Cerasola G et al. White-coat hypertension and cardi- 19 Glen SK et al. White-coat hypertension as a cause of ovascular risk. J Cardiovas Risk 1995; 6: 545–549. cardiovascular dysfunction. Lancet 1996; 348: 654–657. 16 Muscholl MW et al. Changes in left ventricular 20 Stranderg TE, Salomaa V. White coat effect, blood structure and function in patients with white coat pressure and mortality in men: prospective cohort hypertension: cross sectional survey. BMJ 1998; 317: study. Eur Heart J 2000; 21: 1714–1718. 565–570. 21 Gustavsen PH et al. White coat hypertension is a 17 Muldoon MF et al. White-coat hypertension and cardiovascular risk factor. A 10-year follow-up study. carotid artery atherosclerosis: a matching study. Arch J Human Hypertens, this issue. Intern Med 2000; 160: 1507–1512. 22 He FJ, MacGregor GA. Cost of poor pressure control in 18 Mallion JM et al. Clinical value of ambulatory blood the UK: 62000 unnecessary deaths per year. J Human pressure monitoring. J Hyperten 1999; 17: 585–595. Hypertens 2003; 17: 455–457.

Journal of Human Hypertension