Salt Lake City, UT—Does intensive systolic blood–pressure lowering increase the likelihood of developing chronic kidney disease (CKD)? And, if so, are the benefits of decreased negative cardiovascular outcomes worth the risk?
Those are questions explored in a subgroup analysis of the Systolic Blood Pressure Intervention Trial (SPRINT) published in Annals of Internal Medicine.
A team led by researchers from the University of Utah School of Medicine points out that the significance of the reported higher incidence of CKD with intensive systolic blood–pressure (SBP) lowering was unclear.
The researchers sought to examine the effects of intensive SBP lowering on kidney and cardiovascular outcomes and contrast the therapy’s apparent beneficial and adverse effects.
The original SPRINT results urged aggressive antihypertensive therapy to a target SBP of less than 120 mmHg, arguing that would reduce all-cause mortality compared with a target SBP under 140mmHg. The recommendation sparked some controversy, however, because of possible unintended consequences, including kidney effects.
The focus was on the subgroup analysis of 6,662 adults with high blood pressure and elevated cardiovascular risk. Participants had a baseline estimated glomerular filtration rate (eGFR) of at least 60 mL/min/1.73 m2. They were randomly assigned to an intensive or standard SBP goal (120 or 140 mmHg, respectively).
The study team was looking for differences in mean eGFR during follow-up (estimated with a linear mixed-effects model), prespecified incident CKD (defined as a less than 30% decrease in eGFR to a value of less than 60 mL/min/1.73 m2), and a composite of all-cause death or cardiovascular event, with surveillance every 3 months.
Results indicate that the difference in adjusted mean eGFR between the intensive and standard groups was ?3.32 mL/min/1.73 m2 at 6 months; ?4.50 mL/min/1.73 m2 at 18 months; and relatively stable thereafter.
Study authors report that an incident CKD event occurred in 3.7% of participants in the intensive group and 1.0% in the standard group at 3-year follow-up, for a hazard ratio of 3.54. Corresponding percentages for the composite of death or cardiovascular event were 4.9% and 7.1%, respectively, at 3-year follow-up, with a hazard ratio of 0.71.
The researchers note that the study was somewhat limited because long-term data were lacking.
“Intensive SBP lowering increased risk for incident CKD events, but this was outweighed by cardiovascular and all-cause mortality benefits,” study authors conclude.
« Click here to return to Weekly News Update.
Published September 20, 2017