SPRINT Toward New Blood Pressure Targets, with Caution
Boston, MA - Lower blood pressure targets can help prevent heart attacks, strokes, cardiovascular disease and death in chronic kidney disease (CKD) patients, according to data presented at the National Kidney Foundation 2016 Spring Clinical Meetings.
However, lower blood pressure could increase the risk in CKD patients for syncope, acute kidney injury, and hospitalization for hypotension.
“Although we saw an increased risk of acute kidney injury in a small proportion of trial participants, we believe the marked decrease in cardiovascular events and mortality outweighs the risk,” said Michael Rocco, MD, the Vardaman M. Buckalew, Jr. Professor of Internal Medicine/Nephrology at Wake Forest School of Medicine.
These findings were obtained from the Systolic Blood Pressure Intervention Trial (SPRINT) which previously showed that intensive blood pressure control in older adults could reduce heart attacks, strokes and all-cause mortality. Results of the study were so compelling that this multi-center randomized controlled trial was concluded early.
Current Kidney Disease Improving Global Outcomes (KDIGO) recommendation for those with chronic kidney disease is to maintain blood pressure under 140/90 mm Hg, with more stringent targets of under 130/80 mm Hg recommended for those with significant proteinuria. The SPRINT trial measured outcomes in patients who had their systolic blood pressure kept under 120 mm Hg (intensive arm) compared to a control group who maintained their systolic blood pressure between 135 – 140 mm Hg.
Analysis of the SPRINT data indicates that patients with chronic kidney disease (CKD) and mild proteinuria could benefit from the tighter systolic blood pressure control target of less than 120 mm Hg to reduce cardiovascular events and mortality.
However, the tighter blood pressure controls did not correlate with slower kidney function decline. In those participants with CKD present at baseline, there was no difference between the two groups for either a 50% or greater decline in eGFR from baseline or in the need for either dialysis or renal transplantation. In the 6,697 participants without CKD at baseline, a decline in eGFR of 30% or greater to an eGFR of < 60 ml/min/1.73m2 was seen in 127 subjects in the intensive arm and 37 subjects in standard arm (3.8% vs 1.1%, Hazard ratio of 3.49, p < 0.001). Additional information regarding these renal outcomes will be the subject of further analyses.
Those in the intensive arm were also more likely to have serious adverse events and emergency room visits related to acute kidney injury or acute renal failure compared to those in the control group (4.1% vs 2.5% respectively, HR = 1.66, p < 0.01). Analysis of these events to determine both the severity and reversibility of these renal events is currently underway.
Dr. Rocco believes that nephrologists should consider the SPRINT results when determining the optimal blood pressure target for patients with chronic kidney disease. He notes, however, that the manner in which blood pressure is measured in the office is of paramount importance to prevent overtreatment of patients. In the SPRINT trial, the blood pressure used for determination of treatment was based on the average of three blood pressure measurements taken 5 minutes apart, using an appropriately sized cuff. The participants were seated with the back supported. No conversations or other distractions, such as cell phone use, were allowed during the blood pressure measurement or the rest periods between blood pressure measurements.
The NKF 2016 Spring Clinical Meetings are being held April 27 to May 1, in Boston, MA. For additional program information, visit www.NKFClinicalMeetings.org.
The National Kidney Foundation is the leading organization in the U.S. dedicated to the awareness, prevention and treatment of kidney disease. For more information, visit www.kidney.org.