More than half of African Americans with hypertensive CKD will experience renal disease progression long-term despite tight BP control with drugs that block the renin-angiotensin system (RAS).
Lawrence J. Appel, MD, MPH, of Johns Hopkins University in Baltimore, and his colleagues performed a cohort study of 1,094 African Americans with hypertensive renal disease. The patients previously had participated in the African American Study of Kidney Disease and Hypertension (AASK) trial (February 1995 to September 2001). In that study, patients randomized to receive the ACE inhibitor ramipril had a slower rate of CKD progression than those assigned to receive the calcium channel blocker amlodipine or the beta blocker metoprolol.
Dr. Appel’s group looked at the long-term effect of RAS blockade on CKD progression. After a transition phase (October 2001 to March 2002), the researchers initiated their cohort study, which ran from April 2002 to June 2007. All patients were treated with either an ACE inhibitor or an angiotensin receptor blocker. The primary outcome was a composite of a doubling of serum creatinine over trial baseline, development of end-stage renal disease, or death. The maximum duration of follow-up was 12.2 years.
The mean BP in the cohort study was 133/78 mm Hg, which is below the 136/82 mm Hg during the trial. A total of 567 subjects (52%) experienced the primary outcome, the authors reported in Archives of Internal Medicine (2008;168:832-839). In addition, of 576 patients with at least seven years of follow-up, 33.5% experienced a slow decline in renal function.
The investigators concluded that their study “demonstrated that most African Americans with hypertensive CKD who are treated with currently recommended BP therapy continue to progress during the long term. These results highlight the importance of preventing initial kidney damage, the critical need to identify modifiable risk factors, and the requirement to test promising therapies as the earliest stages of CKD.”