Ambulatory blood pressure monitoring during antihypertensive treatment: the case of non-responder patients

OBJECTIVE: To analyse the discrepancies between casual and ambulatory blood pressure in hypertensive patients during treatment. PATIENTS AND METHODS: Patients were gathered intio two groups according to casual diastolic blood pressure (DBP) and antihypertensive treatment: group A (responders) with casual DBP < 90 mmHg administered one or more antihypertensive drugs and group B (non-responders) with DBP >/= 95 mmHg taking two or more antihypertensive drugs, maintained during three consecutive visits at 2-week intervals. For all of them casual blood pressure measurements, 24 h ambulatory blood pressure monitoring and assessment of end-organ damage were performed. RESULTS: The difference between casual blood pressure and average 24 h ambulatory blood pressure were significantly higher for group B than those observed for group A (26 versus 7 mmHg systolic, 16 versus 5 mmHg diastolic). Thirty per cent of the patients in group B and 16% in group A had casual blood pressure more than 20 mmHg higher than awake ambulatory blood pressure, whereas 8% in group B and 20% in group A had higher values for ambulatory than for casual blood pressure. In group A 8% of patients had awake DBP higher than 95 mmHg and 8% had awake DBP 85-95 mmHg. Patients of group A with awake DBP >/= 85 mmHg were younger than those with awake DBP < 85 mmHg (41.4+/-8.8 and 52.1+/-13.4 years, respectively). In patients of group B, there was less end-organ damage in the patients with awake DBP < 85 mmHg than there was in patients with awake DBP >/= 95 mmHg (World Health Organization grade I/II-III, 6/10 and 3/20, respectively). CONCLUSION: The differences between casual and ambulatory blood pressures were higher in the 'non-responder' patients. In group A the small percentage of patients who had persistently higher ambulatory blood pressure were younger. In group B one-quarter of the patients had 'normal' ambulatory blood pressure and less end-organ damage. Ambulatory blood pressure monitoring will be useful for better assessment of hypertension control in a subset of hypertensive patients.