BBB 1994

Methods	Multicentre, prospective, randomized open with blinded end point (PROBE) design
Participants	Adults aged 47 to 67 years were included if their treated DBP was in the range 90 to 100 mmHg on at least three consecutive visits. Specific exclusion criteria were: history of IHD, pathological ECG or both, somatic disorders expected to cause a significant deterioration in health within the next few years or inability to participate. Country: Sweden
Interventions	Standard (unchanged) target: DBP 90 to 100 mmHg Intensive target: DBP ≤ 80 mmHg
Outcomes	Three main questions were asked: Whether DBP ≤ 80 mmHg could be obtained in previously “well‐treated” people with hypertension; Whether additional reduction in blood pressure could be obtained without increasing the incidence or severity of side effects to unacceptable levels; Whether further reduction in DBP would be associated with further reduction in hypertension‐induced cardiovascular complications, or whether such further lowering of blood pressure would be associated with increased morbidity and mortality in accordance with the J‐curve concept.
Notes	Study data have been lost. The principal author (Prof Lennart Hansson) is deceased; Dr Bjorn Dahlöf confirmed that data have not been retained. Bayer was also contacted but confirmed the company does not have any data available for the BBB study. The journal Blood Pressure, in which BBB results were published, confirmed the manuscript received was essentially as the published, and the documentation was destroyed about 10 years before (following Prof Hansson's death). The Swedish Council on Heath Tecnology Assessment assessed the study in a report (No. 170/2) but did not have access to the original data. We also approached the Östra Hospital, where Prof Hansson was working at the time the study was conducted. No records were found, and we were told that the legal requirement to keep records safe expired after 15 years