White coat effect, blood pressure and mortality in men: prospective cohortstudy

Background Because long-term follow-up studies, which also included normote nsive controls, have been lacking, the clinical significance of 'white coat ' effect and of 'white coat' hypertension has remained controversial. Methods and Results Twenty-one-year prospective data was gathered in 536 me n with cardiovascular risk factors at baseline. Blood pressure was measured both by a nurse and by a physician and 'white coat effect' was defined as the difference between the two measurements (physician minus nurse). In add ition, four blood pressure groups were categorized: normotensive (n=259), w hite coat hypertensive (n=18), mildly hypertensive (n=150) and persistently hypertensive (n=109). Comparison of these groups at baseline showed that m en with white coat hypertension had higher levels of metabolic risk factors . Sixty-eight men died during follow-up. The men with a white coat effect > 30 mmHg (n=37) had significantly higher mortality than other men (relative risk 2.2, 95% confidence interval 1.1-4.2). Mortality was significantly hig her in the white coat hypertensive group (33.3%) than in the normotensive g roup (9.5%, P=0.0005 between groups). Relative risk adjusted for baseline r isk factors in the white coat hypertensive group was 3.3 (1.2-7.6) compared with the normotensive group. The development of drug-treated hypertension was also more common (27.8% vs 13.4% in the normotensive group, P<0.0001 be tween groups). Conclusion The results suggest that white coat hypertension or a large whit e coat effect is not an innocent phenomenon. It tends to co-exist with meta bolic risk factors and predicts total and cardiovascular mortality during l ong-term follow-up. (C) 2000 The European Society of Cardiology.