Does intensive systolic blood pressure lowering in older patients increase the likelihood of renal dysfunction?
In this post-hoc analysis of the previously published SPRINT trial, lowering the systolic blood pressure of patients who are at increased risk of cardiovascular events (average age = 66 years) will decrease their risk of cardiovascular disease but increase their likelihood of developing moderate renal dysfunction. It will not, at least over three years, increase their likelihood of developing end-stage renal disease. (Level of Evidence = 1b)
This report is a subgroup analysis of the SPRINT (Systolic Blood Pressure Intervention Trial), which enrolled patients with high blood pressure and elevated cardiovascular risk. This analysis was limited to the 6,662 participants, with a mean age of 66 years, who had a baseline estimated glomerular filtration rate of at least 60 mL per minute per 1.73 m2 and who represented approximately 70% of the total original cohort. The participants were randomly assigned, allocation concealment unknown, to be treated to reach an intensive (120 mm Hg or lower) or standard (140 mm Hg or lower) systolic blood pressure. The actual blood pressure difference between the two groups was an average of 15 mm Hg. Significantly more patients in the lower blood pressure group experienced a significant decline in kidney function, defined as a 30% or greater decline in glomerular filtration rate to less than 60 mL per minute per 1.73 m2 (number needed to treat to harm = 38; 95% confidence interval, 29 to 53). But, as in the full SPRINT report, the risk of death or cardiovascular event over three years was lower with lower systolic blood pressure. None of the participants developed end-stage renal disease. Post-hoc analyses such as this one are risky to interpret, but in this case, the results echo the analysis in the original report.
Study design: Randomized controlled trial (nonblinded)
Funding source: Government
Setting: Outpatient (any)
Reference: BeddhuSRoccoMVTotoRet alSPRINT Research GroupEffects of intensive systolic blood pressure control on kidney and cardiovascular outcomes in persons without kidney disease: a secondary analysis of a randomized trial. Ann Intern Med2017;167(6):375–383.