[Effectiveness of self-measurement of blood pressure in patients with hypertension: the Dioampa study]

OBJECTIVE: To evaluate the effectiveness of self-measurement of blood pressure (SMBP) in controlling hypertension. DESIGN: Randomized, controlled, pragmatic, open study. The unit of randomization was the basic health care unit (BCU), consisting of 1 physician and 1 nurse. All BCUs were randomized to the control group (usual clinical practice, n=94) or to the intervention group (n=86). SETTING: Primary care BCUs throughout Spain. PARTICIPANTS: Patients with poorly controlled essential hypertension, defined as systolic blood pressure > or = 140 or diastolic blood pressure > or = 90 mm Hg. INTERVENTIONS: The patients were given an OMRON HEM-705CP automatic blood pressure monitor on two occasions, for use during 15 days at weeks 6 and 14. Blood pressure was recorded at each visit (baseline, 6, 8, 14, 16, and 24 weeks). Main outcome measures. MAIN OUTCOME VARIABLE: control of blood pressure, considered systolic/diastolic blood pressure <140/90 mm Hg (130/85 in patients with diabetes). RESULTS: 180 BCUs serving 1325 patients (622 in the intervention group, 703 in the control group) participated. Baseline characteristics were similar in both groups. Immediately after the first period of SMBP (week 8) the proportion of patients whose blood pressure was well controlled was 7.6% higher in the intervention group than in the control group (P=.01). After the second period of SMBP (week 16) the difference between groups decreased to 4.1% (P=.27). At the end of the study the difference was 4.9% (P=.19). CONCLUSIONS: Self-measurement of blood pressure was effective in controlling blood pressure in the short term, but its effects faded over time.