Blood pressure targets for patients with diabetes or kidney disease.

Abstract

The most recent scientific guideline statements from foundations and societies dealing with diabetes and kidney disease argue for blood pressure (BP) goals lower than 130/80 mm Hg, but whether the evidence from properly done clinical trials supports this BP level remains questionable. A review of all the evidence suggests that almost all of the data come from retrospective data analyses of randomized cardiovascular and chronic kidney disease (CKD) trials. Meta-analyses of all clinical trials to date demonstrate that reducing BP reduces risk for stroke and coronary heart disease, but none have achieved a mean BP goal of less than 130/80 mm Hg. In fact, only two prospective trials achieved a BP lower than 130/80 mm Hg in people with type 2 diabetes, as did three trials in advanced proteinuric CKD. Of these, one of the two diabetes trials showed a benefit for overall cardiovascular risk reduction, and two of the three kidney disease trials showed a benefit on slowing of advanced CKD. Of note, however, these two trials in CKD had baseline average proteinuria rates of more than 500 mg/day. No benefit of a lower BP was seen in microalbuminuric CKD. Therefore, the totality of the prospective randomized trial evidence indicates that a BP less than 130/80 mm Hg is not defensible to slow nephropathy progression unless proteinuria levels are at least 500 mg/day, and it does not reduce overall cardiovascular events in diabetes. Stroke benefit was uniformly seen at BP levels less than 130/80 mm Hg, however. Therefore, newer guidelines are emerging that state that the BP goal for most people is lower than 140/90 mm Hg with level IA or IB evidence, and that levels lower than 130/80 mm Hg are defensible only if advanced proteinuric CKD is present or stroke risk is very high (i.e., history of prior stroke or several risk factors for stroke, including hypertension, smoking, diabetes mellitus, dyslipidemia).