This trial randomized 1,094 African American adults with hypertension and CKD (defined by a GFR 20-65 mL/min/1.73 m2) without a clear secondary cause of CKD to a BP target [intensive BP with MAP ≤92 mm Hg (equivalent BP of 130/80) or usual MAP 102-107 mm Hg (equivalent BP of 140/90)] and BP agent (ramipril, amlodipine, or metoprolol) in a 2x3 factorial design. The primary outcomes were the slope of eGFR change and progression of CKD or death. The secondary outcome was a composite outcome that included a reduction in eGFR by 50% or by 25mL/min/1.73m2, ESRD, or death. After the original AASK trial, a 5 year (2002-2007) cohort study of AASK participants took place (Appel 2008)
At 4 years, there was no difference in the primary outcome by BP target in the population as a whole. Also, there was no specific medication associated with a reduction in eGFR slope. Rampirl, though, reduced the secondary composite outcome as compared to amlodipine and metoprolol. As mentioned above, in all study participants, a more aggressive BP reduction was not associated with better renal outcomes. However, when participants with UPCR > 0.22 (median proteinuria in these patients was 1000mg/day) were examined, there was a reduction in primary outcome in the trial phase. A reduction in the primary outcome and the secondary outcomes were reduced when both trial and cohort phases were taken into account (Appel 2010).
Use of the ACE-inhibitor ramipril was associated with fewer CKD events (slowing the rate of GFR decline) or death. The AASK trial in part solidified the use of ACE-inhibitors among patients with CKD. In summary, this trial gave us 3 pieces of information, that more intensive BP management in CKD did not result in an improvement in renal outcomes in this population as a whole, but ACE inhibitors did. It also showed that in patients with significant proteinuria (~1g/day), intensive BP control resulted in improvement in renal outcomes.
The AASK Trial: Wright Jr, J. T., Bakris, G., Greene, T., Agodoa, L. Y., Appel, L. J., Charleston, J., ... & Hebert, L. (2002). Effect of blood pressure lowering and antihypertensive drug class on progression of hypertensive kidney disease: results from the AASK trial. Jama, 288(19), 2421-2431.
AASK Cohort Study: Appel, L. J., Wright, J. T., Greene, T., Kusek, J. W., Lewis, J. B., Wang, X., ... & Contreras, G. (2008). Long-term effects of renin-angiotensin system–blocking therapy and a low blood pressure goal on progression of hypertensive chronic kidney disease in african americans. Archives of Internal Medicine, 168(8), 832-839.
AASK Trial PMID: 12435255
Useful summaries of the AASK Trial: Wiki Journal Club
Other references: AASK Trial investigator publication that synthesizes the results of the original AASK Trial and the Cohort phase: Appel, L. J., Wright Jr, J. T., Greene, T., Agodoa, L. Y., Astor, B. C., Bakris, G. L., ... & Gabbai, F. B. (2010). Intensive blood-pressure control in hypertensive chronic kidney disease. New England Journal of Medicine, 363(10), 918-929.