It appears that Dr Kendall focuses more on tradition than evidence in his stance on blood pressure (BP) goals in diabetes. To fully appreciate this assertion, one must examine the history of how <130/80 mm Hg attained its stature as the BP goal for persons with diabetes. Dr Kendall has done an excellent job summarizing past guidelines but unfortunately, the level of evidence used for almost all previous guidelines to support the goal of <130/80 mm Hg is level C.
Arguing from guidelines for a given construct such as BP goal is never a good idea. The executive committee of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) was fully aware that the level of evidence supporting <130/80 mm Hg for patients with diabetes was poor. One concern, however, was that physician inertia would intervene if the goal supported by prospective evidence was put forth, ie, <140/90 mm Hg, leading to many people with diabetes having systolic BP levels well above 140 mm Hg. Serving on other guideline committees at this same time, no group wanted to disagree with the JNC recommendation, so, as a result, the lower goal of BP was promulgated.
Based on the evidence, there are three prospective trials that clearly support the assertion of a lower BP being associated with fewer cardiovascular events; unfortunately, none are at mean systolic BP level <130 mm Hg and only one has a mean diastolic level <80 mm Hg (United Kingdom Prospective Diabetes Study [UKPDS]: 144/82 mm Hg; Hypertension Optimal Treatment [HOT] trial: 140/81 mm Hg, and Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation [ADVANCE]: 134.5/74 mm Hg).1–3 Thus, these data support a goal BP <140/90 mm Hg, as is recommended in most other patients with hypertension, not <130/80 mm Hg. Further support for the argument of a higher goal comes from Dr Kendall himself, who notes the results of the more recent Action to Control Cardiovascular Risk in Diabetes—BP Arm [ACCORD BP] trial, which failed to show an additional benefit on cardiovascular event reduction at a mean systolic BP of 119 mm Hg.4 A post hoc analysis of 6400 patients with type 2 diabetes from the International Verapamil-Trandolapril Study (INVEST) also failed to show additional cardiovascular risk reduction among patients who achieved a BP <130/80 mm Hg.5
While the evidence fails to support a lower BP goal to reduce coronary events, there was a risk reduction in stroke events both in ACCORD and the Appropriate Blood Pressure Control in NIDDM (ABCD) trial.4,6,7 A number of other studies also demonstrate that when systolic pressures fall to 125 mm Hg to 130 mm Hg, a reduction in stroke events but not coronary disease occurs. Therefore, should one focus only on stroke risk while increasing risk of coronary events at lower diastolic BP levels, or posit another solution?
One needs a perspective on BP goals, and I would propose the following: preventing a rise in systolic BP when the level is around 140 mm Hg is far different than lowering systolic BP to this level once it has been elevated for many years at levels above 160 mm Hg. The ACCORD trial taught us that aggressive control of glucose to very low levels in people who had poor control for many years was not beneficial and actually increased cardiovascular events, and similar findings exist for BP. So what is the answer? The goal should be individualized based on what the patient’s vascular physiology will allow. Those with wide pulse pressures or many years of poor BP control will be less likely to tolerate reductions of BP to <130/80 mm Hg but can generally tolerate levels to <140/90 mm Hg. It could be argued that if the physiology allows reduction of BP to <130/80 mm Hg, one should try to achieve it, but, if not, <140/90 mm Hg should be the minimum achieved. Thus, individualizing therapy is the key since patients with a shorter duration of hypertension without advanced vascular disease should be able to achieve a lower goal and have a lower stroke risk.
A proposal to achieve BP goals in people with diabetes was put forth by us recently7 and is reiterated as follows: (1) It is recommended that all patients with diabetes mellitus have a goal BP <140/90 mm Hg. (2) An attempt should be made to lower the systolic pressure below 130 mm Hg to 135 mm Hg (preferably <130 mm Hg) if it can be achieved without producing significant side effects. (3) For patients who fulfill the entry criteria of ACCORD BP, ie, type 2 diabetes plus either cardiovascular disease or at least two additional risk factors for cardiovascular disease, the suggestion is that the risks and burdens of aiming for a goal systolic pressure of <120 mm Hg (more side effects, extra patient visits, and increased cost) plus the lack of experience of almost all physicians in attaining such a goal may be too great a burden to achieve the small reduction in stroke that may be attained (absolute benefit: 1 in 89 patients at 5 years). However, such a goal may be considered in highly motivated patients who would accept more aggressive antihypertensive therapy to further reduce their risk of stroke.