INVEST in print: Tight diabetic BP control not linked to improved CVD outcomes
MedWire News: Maintaining the systolic blood pressures (SBP) of patients with diabetes and coronary artery disease (CAD) at less than 130 mmHg instead of between 130 and 140 mmHg, does not improve cardiovascular (CV) outcomes, researchers report.
"We have shown for the first time, to our knowledge, that decreasing SBP to lower than 130 mmHg in patients with diabetes and CAD was not associated with further reduction in morbidity beyond that associated with SBP lower than 140 mmHg," says the team, led by Rhonda Cooper-DeHoff (University of Florida, Gainesville, USA).
The study showed that lowering SBP to less than 130 mmHg was in fact associated with an increase in risk for all-cause mortality, which persisted in the long term.
Results of the study, initially unveiled at the American College of Cardiology annual scientific sessions earlier this year and reported at the time by MedWire News, are now published in this week's issue of the Journal of the American Medical Association.
The researchers performed a secondary analysis of the International Verapamil SR-Trandolapril Study (INVEST), comparing the clinical outcomes of 6400 patients (mean age 66 years) with diabetes, hypertension, and CAD.
The patients, from 14 different countries, were observed from September 2000 to March 2003. Extended follow-up was conducted via the National Death Index from March 2003 to August 2008 for US patients only.
All patients received antihypertensive therapy in the form of a calcium antagonist or beta blocker followed by an ACE inhibitor, a diuretic, or both. The patients were assigned to a tight control group if they had a SBP less than 130 mmHg, a usual control group if SBP was 130-139 mmHg (30.8%), and an uncontrolled group if SBP was 140 mmHg or greater (34%).
Adverse CV outcomes were defined as all-cause death, non-fatal myocardial infarction or nonfatal stroke. Patients in the usual control group had a lower CV event rate than patients in the uncontrolled group, at 12.6% and 19.8%, respectively (p<0.001). However, there was little difference between the usual control and tight control patients, at 12.6% and 12.7%, respectively.
After extended follow-up and adjustment for baseline variables, a 15% higher risk for all-cause mortality was found among the tight control group compared with the usual control group (p=0.04).
However, on further analysis, the increase in all-cause mortality appeared when SBP was less than 115 mmHg and continued to increase further inversely to SBP after this level.
They conclude: "At this time, there is no compelling evidence to indicate that lowering systolic BP below 130 mmHg is beneficial for patients with diabetes; thus emphasis should be placed on maintaining systolic BP between 130 and 139 mmHg while focusing on weight loss, healthful eating, and other manifestations of cardiovascular morbidity."
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By Lauretta Ihonor