Blood pressure control--effects on diabetic nephropathy progression: how low does blood pressure have to be?

Hypertension and diabetes are independent risk factors for both cardiovascular disease and renal complications. Coexistence of these comorbid conditions predisposes the patient to a much greater risk of progression to end-stage renal disease. Combined with the increased cardiovascular mortality, this has led to recent Joint National Committee-VI recommendations for the initiation of antihypertensive therapy for people with diabetes at a blood pressure of 130/85 mm Hg, a level lower than that recommended for the nondiabetic population. Results of a review of recently published investigations on the effects of blood pressure on diabetic nephropathy progression are presented in this article. This review finds evidence to support reducing the mean arterial blood pressure to levels below 95 mm Hg, a level that is even lower than the blood pressure of 130/80 mm Hg (mean arterial pressure of 97 mm Hg) recommended by the American Diabetes Association and National Kidney Foundation. The effect of blood pressure on renal disease progression is linear and appears to have no lower threshold for the benefits of blood pressure reduction on limiting nephropathy progression. The answer to the question of how low does blood pressure have to be to minimize the effects of blood pressure on diabetic nephropathy progression might be "the lower, the better."