The effect of antihypertensive treatment with dihydropyridine calcium antagonists on white-coat hypertension. 
OBJECTIVE: To investigate the interrelations between blood pressure variables and treatment effects in white-coat and established hypertensive patients.  DESIGN: A substudy on data from a randomized clinical trial on two dihydropyridine calcium antagonists, in which treatment intensity relied on office blood pressure, but with ambulatory blood pressure recordings performed before and after treatment.  PATIENTS: Ninety-two hypertensive patients from general practices.  RESULTS: Office and ambulatory blood pressures were only poorly correlated (r = 0.27-0.49).  There was no significant correlation between treatment effects evaluated in terms of office and ambulatory blood pressures.  Seventeen patients were classified as white-coat hypertensives; these differed in that their office blood pressure declined more with placebo, but similarly when administered active treatment, whereas their ambulatory blood pressure was not affected.  An initial ambulatory blood pressure amounting to 127.4/84.8 mmHg was associated with no ambulatory treatment effect on average.  CONCLUSION: These findings expose the shortcomings of office blood pressure measurements and strengthen the conception that white-coat hypertensives should not be treated pharmacologically.