3c.09: Strategies for Classifying Patients Based on Office, Home and Ambulatory Blood Pressure Measurement.

OBJECTIVE Hypertension guidelines propose home (HBP) or ambulatory (ABP) blood pressure monitoring as indispensable after office measurement (OBP). However, whether preference should be given to HBP or ABP remains undetermined. DESIGN AND METHOD We recruited 831 consecutive patients (mean age, 50.6 years; 49.8% women) referred for ABP monitoring to our clinic, if they had never taken (∼90%) or had discontinued antihypertensive medication for at least 2 weeks (∼10%). SpaceLabs 90217 monitors were programed to obtain 24-h ABP recordings. OBP was measured at three visits at 1 week intervals using the Omron HEM-7051 device. Patients were requested to measure their HBP three times in the morning and three times in the evening at 1 minute intervals during 7 consecutive days. We applied hypertension guidelines for cross-classification of patients based on OBP, HBP and ABP into normotension (NT) or white-coat (WCH), masked (MH) or sustained (SH) hypertension. Aortic pulse wave velocity was measured by the SphygmoCor system and a first-morning urine sample was collected for the measurement of urinary albumin-to-creatinine ratio. RESULTS Based on OBP and HBP, the prevalence of NT, WCH, MH and SH was 442 (53.2%), 61 (10.3%), 166 (20.0%) and 162 (19.5%), respectively. Using daytime ABP (30 readings from 8 AM to 6 PM) instead of HBP, confirmed the cross-classification based on OBP and HBP in 575 patients (69.2%), downgraded risk from MH to NT (n = 24) or from SH to WCH (n = 9) in 33 (4.0%), but upgraded risk from NT to MH (n = 179) or from WCH to SH (n = 44) in 223 (26.8%). Analyses based on 24 h ABP were confirmatory. In adjusted analyses, both the urinary albumin-to-creatinine ratio (+20.6%; CI, 4.4-39.3) and aortic pulse wave velocity (+0.30 m/s; CI, 0.09-0.51) were higher in patients who moved up to a higher risk category. Both indexes of target organ damage were positively associated (P < 0.008) with the odds of being reclassified. CONCLUSIONS For reliably diagnosing HT and starting treatment, OBP should be followed by ABP monitoring. Using HBP instead of ABP misses the high-risk diagnoses of MH or SH in over 25% of patients.