Prognostic Impact of Different Definitions of White-Coat Hypertension

BACKGROUND Different definitions of white-coat hypertension (WCH) may explain its variable outcome across studies. METHODS In an Italian study started in 1986, we followed 3,153 people with (office blood pressure (BP) >=140/90 mmHg) and 457 without office hypertension for a mean of 10.4 years. None had previous cardiovascular disease. All underwent 24-h ambulatory BP (ABP) monitoring. We defined white-coat hypertension (WCH) as an average 24-h ABP < 130/80 mmHg or <125/75 mmHg. The primary outcome was a composite of major adverse cardiovascular events (MACE) and all-cause mortality. RESULTS Baseline office BP was 156/97 mmHg in people with and 127/81 mmHg without hypertension. At follow-up, MACE events were 344 and 23, and all-cause deaths were 318 and 24 in people with and without hypertension, respectively. Compared to normotensive group, MACE risk was not higher in people with WCH and 24-h ABP < 125/75 mmHg (hazard ratio (HR), 0.94; 95% confidence interval (CI), 0.42-2.10). Compared to normotensive group, MACE risk was higher in people with WCH and 24-h ABP < 130/80 mmHg (HR: 1.79; 95% CI, 1.07-2.29). All-cause death did not differ between the normotensive group and people with WCH and 24-h ABP < 125/75 mmHg (HR 1.37; 95% CI, 0.68-2.73), but it was higher than in the normotensive group when WCH was defined by a 24-h ABP < 130/80 mmHg (HR 1.82; 95% CI, 1.55-3.58). CONCLUSIONS WCH defined by an average 24-h ABP < 125/75 mmHg identifies people at low risk of MACE and death in the long term. Even modestly above these threshold values, the risk associated with WCH increases.