Is white-coat hypertension a harbinger of increased risk?

White-coat hypertension is defined by elevated office and normal out-of-office blood pressure (home or ambulatory) in untreated subjects. This condition is common in clinical practice and requires appropriate work-up for detection and management. Many studies have examined the relationship between white-coat hypertension and cardiovascular risk but with marked heterogeneity in the definitions and methodology applied. Thus, the results have been inconsistent leading to confusion in scientific research and clinical practice. Some but not all the relevant studies suggested that white-coat hypertension is associated with subclinical target-organ damage, yet the cross-sectional design of these studies and the fact that these indices are only surrogate end points do not allow firm conclusions to be drawn. In recent years, longitudinal studies have examined the prognostic significance of white-coat hypertension in terms of cardiovascular morbidity and mortality. Most of them indicate that white-coat hypertensive compared with normotensive subjects present a moderate-in most cases not significant-increase in risk. Meta-analyses of raw data from large databases, such as the International Database on Ambulatory blood pressure and Cardiovascular Outcomes (IDACO) and the International Database on HOme blood pressure in relation to Cardiovascular Outcomes (IDHOCO) allowed separate powered analyses in untreated subjects and provided a clearer picture regarding the modest risk associated with white-coat hypertension, especially in the long term. White-coat hypertension is regarded as an intermediate phenotype between normotension and hypertension associated with increased risk of developing sustained hypertension, and therefore requires regular follow-up using nonpharmacological measures.