Sustainability of blood pressure control
The New England Journal of Medicine recently published a long-term follow-up study to determine the impact of tight control over blood pressure among patients with Type II Diabetes. Researchers at the United Kingdom Prospective Diabetes Study (UKPDS) wanted to see whether the risk reductions achieved during periods of tight control over blood pressure would be sustainable after those controls were relaxed.
Out of 5000 patients with newly diagnosed type II diabetes, they randomly assigned more than 1000 that had hypertension to either tight or more relaxed blood-pressure control regimes. Patients with blood pressures greater than or equal to 160/90 mm Hg were randomly allocated to tight-control, aiming for less than 150/85 mm Hg with either an angiotensin-converting enzyme inhibitor or a Beta-blocker or to less-tight-control aiming for less than 200/105 mm Hg. Patients who underwent post-trial monitoring were asked to attend annual UKPDS clinics for the first 5 years, but no attempt was made to maintain their previously assigned therapies.
What was the result? After the trial, blood-pressure levels fell in the less-tight-control group and rose in the tight-control group, with no significant differences between the groups after 2 years. In line with this equalization of blood pressures, there were no significant risk reductions observed between the groups 10 years after the trial.
Differences in blood pressure between the two groups during the trial disappeared within 2 years after termination of the trial. Significant relative risk reductions found during the trial for any diabetes-related end point, diabetes-related death, microvascular disease, and stroke in the group receiving tight, as compared with less tight, blood-pressure control were not sustained during the post-trial follow-up.
