Very poor agreement between routine outpatient clinic office and ambulatory blood pressure: time to improve an old hospital outpatient clinic routine?

We investigated the agreement between elevated outpatient clinic office blood pressure (OC-OBP) as measured in the daily routine in our University Hospital Cardiology Outpatient Clinic and subsequent awake ambulatory blood pressure (AABP).In all patients referred for ambulatory blood pressure monitoring from our Cardiology Outpatient Clinic, we identified OC-OBP and changes in medication in the period from 1 January 2014 to 15 September 2015. The AABP was used as a reference measurement for the OC-OBP.A total of 183 patients were included in the study. Their mean age was 62.1±14.0 years and 49% were women. The mean systolic OC-OBP was 166.8±17.9 mmHg and the difference between the mean systolic OC-OBP and AABP was 28.0±19.5 mmHg (P<0.001) with 95% limits of agreement from -10.2 to +66.3 mmHg. The difference in mean systolic OC-OBP and AABP was 18.6±14.7 mmHg in patients less than 45 years (n=21), 24.8±18.2 mmHg in patients 45-74 years (n=121) and 42.3±18.5 mmHg in patients more than or equal to 75 years (n=41). In 32 (17%) of the patients, the antihypertensive treatment was intensified before the AABP, but in nine (28%) of these patients, the antihypertensive treatment was reduced again after the AABP because of low blood pressure.Routine OC-OBP in a busy cardiology clinic agrees poorly with AABP and may lead to unnecessary treatment and pharmacologically induced symptomatic hypotension, particularly in elderly patients. The results of this study urgently call for alternative solutions to routine OC-OBP in hospital outpatient clinics.