Manning et al highlight an important point, well described but less well recognised in clinical practice.1 Their study demonstrates the practical implications of acting upon blood pressure (BP) values and the variations obtained at different times through various methods adopted to measure BP, especially in this era of the phasing out of mercury sphygmomanometers.2 However, we take lament over their comments of identifying the white-coat effect group (∼30%) to avoid costs of additional treatment. There is an increasing body of evidence to suggest that white-coat hypertension (WCH) is not so benign after all.3 Indeed, many studies have suggested that WCH was associated with significant end-organ damage.3
As an illustrative example; Strandberg et al,4 evaluated prospective data over 21 years of 536 businessmen with cardiovascular risk factors at baseline and found that men with white coat effect of >30 mmHg had significantly higher mortality than the normotensive men. Gustavsen et al,5 contributed further to the debate and suggested that WCH should be regarded as a cardiovascular risk factor. Their study was a follow-up study on 420 patients with hypertension newly diagnosed by their GP and 146 normal controls; where 18.1% of the 420 hypertensives had WCH. With a mean duration of follow-up of 10.2 years, first events were recorded in 18.4% of the WCH group compared with 16.3% in the established hypertension group. The other main finding of this study was an increased cardiovascular risk in WCH compared to normotensive controls.
This has particular inference, given the recent study by Mant et al demonstrating that for 80% of the patients in UK primary care, systolic BP was above the targets set by the British Hypertension Society, despite the fact that the practices selected were active in research and the BP control may have been better than in the UK as a whole with notable paucities in aggressive combination therapy.6 One recent report,7 on primary care physicians' choices of antihypertensive therapy for subjects with type 2 diabetes diagnosed with hypertension found considerable variation between practices that were not explained by adjusting for age, sex, prevalent coronary heart disease or study year; while trends in drug utilisation were consistent with the evolving evidence base but there were still wide variations in between practices. Indeed, the burden of hypertension on stroke and cardiovascular disease is enormous — 21 400 stroke deaths and 41 400 ischemic heart disease deaths (approximately 42 800 strokes and 82 800 ischaemic heart diseases saved, making a total of 125 600 events saved) each year in the UK.8
Thus, the emphasis by most BP management guidelines calling attention to the need for more aggressive treatment targets cannot be stressed any further, given the vast amount of disability-adjusted life-years and mortality associated with the global burden of hypertension, which is indeed a major public health challenge.9
- © British Journal of General Practice, 2006.
