Banegas JR, et al. - Researchers wanted to see how blood pressure measured in the clinic (clinic blood pressure) and 24-hour ambulatory blood pressure were related to all-cause and cardiovascular mortality in a large cohort of patients in primary care. Compared to clinic blood-pressure measurements, ambulatory blood-pressure measurements more strongly predicted all-cause and cardiovascular mortality. White-coat hypertension was not benign, and a higher risk of death was seen with masked hypertension vs sustained hypertension.

Methods

• Data from a registry-based, multicenter, national cohort that included 63,910 adults recruited from 2004 through 2014 in Spain was analyzed.
• Researchers examined clinic and 24-hour ambulatory blood-pressure data in the following categories: sustained hypertension (elevated clinic and elevated 24-hour ambulatory blood pressure), “white-coat” hypertension (elevated clinic and normal 24-hour ambulatory blood pressure), masked hypertension (normal clinic and elevated 24-hour ambulatory blood pressure), and normotension (normal clinic and normal 24-hour ambulatory blood pressure).
• They performed analyses with Cox regression models, adjusted for clinic and 24-hour ambulatory blood pressures and for confounders.

Results

• During a median follow-up of 4.7 years, death was reported for 3,808 patients; 1,295 of these patients died from cardiovascular causes.
• In a model that included both 24-hour and clinic measurements, a stronger association of 24-hour systolic pressure with all-cause mortality was noted (hazard ratio, 1.58 per 1-SD increase in pressure; 95% confidence interval [CI], 1.56 to 1.60, after adjustment for clinic blood pressure) when compared to the clinic systolic pressure (hazard ratio, 1.02; 95% CI, 1.00 to 1.04, after adjustment for 24-hour blood pressure).
• They noted that corresponding hazard ratios per 1-SD increase in pressure were 1.55 (95% CI, 1.53 to 1.57, after adjustment for clinic and daytime blood pressures) for nighttime ambulatory systolic pressure and 1.54 (95% CI, 1.52 to 1.56, after adjustment for clinic and nighttime blood pressures) for daytime ambulatory systolic pressure.
• Across subgroups of age, sex, and status with respect to obesity, diabetes, cardiovascular disease, and antihypertensive treatment, these relationships remained consistent.
• Masked hypertension was more strongly linked to all-cause mortality (hazard ratio, 2.83; 95% CI, 2.12 to 3.79) vs sustained hypertension (hazard ratio, 1.80; 95% CI, 1.41 to 2.31) or white-coat hypertension (hazard ratio, 1.79; 95% CI, 1.38 to 2.32).
• Results similar to those seen with all-cause mortality were seen with cardiovascular mortality.