Long-term cardiovascular risk of white-coat hypertension with normal night-time blood pressure values.

BACKGROUND

The prognostic impact of white-coat hypertension (WCHT) is still a matter of debate and controversy. Night-time blood pressure (NBP) is related strongly to cardiovascular (CV) prognosis, but this has not been considered currently in the definition of WCHT.

PATIENTS AND METHODS

We investigated the long-term CV prognosis of 2659 patients submitted at admission to 24 h-ambulatory blood pressure (BP) monitoring divided into three groups: normotension (NT) (n=812; 59% female; ageing 49±13 years), sustained hypertension (SHT) (n=1230; 56% female; ageing 51±13 years) and WCHT (n=617; 55% female; ageing 50±3 years) defined as office BP of at least 140/90 mmHg, daytime BP less than 135/85 mmHg and NBP less than 120/70 mmHg.

RESULTS

The median follow-up was 7.6 years (range: 0.4-24.4), during which a total of 257 CV events (36 fatal) occurred (46% strokes, 32% coronary and 22% others), 38 in NT, 31 in WCHT and 188 in SHT. The event rate per 100 patient-years was 0.60 in the WCHT group, 0.66 in the NT group and 2.09 in the SHT group. Cox's regression analysis adjusted for covariables showed a higher risk of CV events in patients with SHT than WCHT [hazard ratio (HR)=2.230, 95% confidence interval: 1.339-3.716, P=0.002], whereas there was no difference between WCHT and NT groups. Event-free survival was significantly different from SH versus WCHT and NT groups. Within the group of WCHT, 29% of patients received sustained antihypertensive medication during the follow-up, but the HR of CV events between WCHT either treated or not treated did not differ: HR=0.76 (95% confidence interval: 0.37-1.51, P=0.42).

CONCLUSION

In patients with WCHT defined by normal daytime and NBP values, the risk of CV events was significantly lower than that of SHT and similar to that of NT patients, suggesting that NBP should be included in the WCHT definition and in its prognostic stratification.