The BBB Study: The Effect of Intensified Antihypertensive Treatment on the Level of Blood Pressure, Side-Effects, Morbidity and Mortality in “Well-Treated” Hypertensive Patients

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Abstract
The BBB study (Swedish for Behandla Blodtryck Battre or Treat Blood Pressure Better) was a multicenter trial designed to investigate three aspects of antihypertensive treatment: i) Is it possible to lower the diastolic blood pressure further in “well-treated” hypertensive patients through intensified therapy? ii) Can this aim be fulfilled without increasing the incidence or severity of side-effects? iii) If i) and ii) can be answered in the affirmative, will the further reduction in diastolic blood pressure be associated with a further reduction in hypertension-associated mortality and morbidity? Altogether 2127 hypertensive men and women with an average age of 59.8 years (46–71) were recruited at 142 primary health care centers in Sweden. Approximately 10 000 patient-years were accumulated. All patients had treated essential hypertension and all had diastolic blood pressures in the range 90–100 mmHg on three consecutive visits before entering the study. The patients were randomized to either intensified treatment aiming at a blood pressure ± 80 mmHg diastolic (group A) or to unchanged therapy (group B). A difference between group A and group B in diastolic blood pressure of 7–7.5 mmHg was achieved for > 4 years. Adverse effects were studied in detail in 100 randomly selected patients from each group using a special questionnaire and a visual analogue scale. The adverse effect score fell significantly in group A but remained unchanged in group B. Regarding cardiovascular morbidity and mortality there were no significant differences between groups A and B, the total number of strokes and myocardial infarcts being 28 in group A and 29 in group B. It is concluded that blood pressure can be further reduced in “well-treated” hypertensive patients by intensified treatment. This does not increase the number or severity of adverse effects; in fact, the reverse was observed. No difference regarding cardiovascular morbidity and mortality was observed, but this may be due to the relatively small number of patients included. A larger study with sufficient statistical power is therefore warranted.