In May I commented on a study in the New England Journal of Medicine that failed to show a benefit in lowering systolic blood pressure below 130 mm Hg. Well, now there’s another such study. This one is in the Journal of the American Medical Association. “Patients were categorized into 3 groups by their average systolic BP while taking study medication: tight control, less than 130mmHg; usual control, 130 mm Hg to less than 140 mm Hg; or uncontrolled, 140 mm Hg or higher.” The paper’s last paragraph is below:
In conclusion, our data from this post hoc analysis in the cohort of patients with diabetes enrolled in INVEST [which was a prospective, randomized trial comparing clinical outcomes of 22 576 patients with hypertension and CAD] indicate that tight control of systolic BP was not associated with improved cardiovascular outcomes compared with usual control. At this time, there is no compelling evidence to indicate that lowering systolic BP below 130mmHg is beneficial for patients with diabetes; thus, emphasis should be placed on maintaining systolic BP between 130 and 139 mm Hg while focusing on weight loss, healthful eating, and other manifestations of cardiovascular morbidity to further reduce long-term cardiovascular risk.
It had seemed to almost everyone who thought about vascular disease in patients with diabetes that aiming for a blood pressure of about 120 was a good idea. But the data seem to contradict our thinking. It’s discouraging to concede how often really good ideas turn out to be wrong. Humility belongs not just to medical science, it should be generously applied to almost every surface.
What if the diabetics where separated into good and poor control? Maybe it does nothing for poorly controlled diabetics because it is of smaller effect than the control. Did they look at different groups?
By control I mean blood glucose control not blood pressure
These investigators did not look at glycemic control. There was a highly significant difference in adverse outcomes between usual BP control and the uncontrolled group, thus demonstrating a beneficial effect of BP control. When BP was lowered even further there was no additional benefit. Glycemic control has clearly been shown to be beneficial, but at the price of increased hypoglycemic reactions. Stratifying patients by Hg A1C and then looking at BP control under conditions of good,bad and indifferent glucose control would likely require a study of much greater power. Though they don’t say anything to this effect, I think they are assuming that glucose control randomized out.
What did you think about this recommendation prioir to these articles (recommendation that still a guideline / JNC VII)? Did you believe that lowering BP below 130 or 120 was a good idea in most diabetics?
I thought it was before these data came out, but the facts are the facts. I’ve been wrong about so many other things that another error doesn’t change my average very much.
I think the best practice is to get blood pressure as low as you can without side effects and without using more than two anti-hypertensive drugs. I realize that this (2 drugs) is not possible in many patients, especially elderly patients. But BP in these older patients is typically not anywhere near 120 mm Hg. It appears we’re going to get back to 140/90 as the goal for most patients.