Intensively reducing systolic blood pressure to less than 120 mm Hg increases the risks for chronic kidney disease (CKD), but concurrently decreases the chances of premature death, according to a secondary analysis of SPRINT (Systolic Blood Pressure Intervention Trial, NCT01206062).
The study included 6662 hypertensive patients (average age 66 years) without diabetes who were at increased risk for cardiovascular disease and who had a baseline estimated glomerular filtration rate (eGFR) of at least 60 mL/min/1.73 m2. Investigators randomly assigned patients to intensive or standard treatment to reduce systolic blood pressure to less than 120 mm Hg or 135 to 139 mm Hg, respectively. At each visit, 3 blood pressure readings were taken using an automated system after 5 minutes of quiet rest, and then averaged. The researchers defined CKD as a more than 30% drop in eGFR to below 60 mL/min/1.73 m2.
The average eGFR was 3.32 and 4.50 mL/min/1.73 m2 lower in the intensive than standard group at 6 and 18 months, respectively, Srinivasan Beddhu, MD, of the University of Utah in Salt Lake City, and colleagues reported online in Annals of Internal Medicine. By 3 years, CKD had developed in 3.7% of the intensive group and 1.0% of the standard group. A composite of death or cardiovascular events occurred in 4.9% vs 7.1%, respectively. At 3 years, the intensive group had a 2.6% increase in the absolute risk of incident CKD and a 2.2% lower absolute risk of a composite of cardiovascular event and death compared with the standard group. The investigators calculated that 38 patients would need receive intensive treatment for 1 case of asymptomatic CKD to develop within 3 years, and 46 would need to be treated to prevent 1 cardiovascular event or death.
“We believe that an asymptomatic CKD event is benign compared with a cardiovascular event or death; therefore, the benefits of the intervention outweigh the risks, at least for the duration of the current study,” Dr Beddhu and the team wrote. “However, we acknowledge that some patients and providers might consider incident CKD to be more important than a cardiovascular event or death.”
Notably, none of the patients with CKD progressed to end-stage renal disease. The team plans to assess the long-term prognosis of the CKD patients with an acute drop in eGFR.
Beddhu S, Rocco MV, Toto R, et al. Effects 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 Med. doi: 10.7326/M16-2966