Effects of Intensive BP Control in CKD

Abstract

The appropriate target for BP in patients with CKD and hypertension remains uncertain. We report prespecified subgroup analyses of outcomes in participants with baseline CKD in the Systolic Blood Pressure Intervention Trial. We randomly assigned participants to a systolic BP target of <120 mm Hg (intensive group; n=1330) or <140 mm Hg (standard group; n=1316). After a median follow-up of 3.3 years, the primary composite cardiovascular outcome occurred in 112 intensive group and 131 standard group CKD participants (hazard ratio [HR], 0.81; 95% confidence interval [95% CI], 0.63 to 1.05). The intensive group also had a lower rate of all-cause death (HR, 0.72; 95% CI, 0.53 to 0.99). Treatment effects did not differ between participants with and without CKD (P values for interactions ≥0.30). The prespecified main kidney outcome, defined as the composite of ≥50% decrease in eGFR from baseline or ESRD, occurred in 15 intensive group and 16 standard group participants (HR, 0.90; 95% CI, 0.44 to 1.83). After the initial 6 months, the intensive group had a slightly higher rate of change in eGFR (-0.47 versus -0.32 ml/min per 1.73 m² per year; P<0.03). The overall rate of serious adverse events did not differ between treatment groups, although some specific adverse events occurred more often in the intensive group. Thus, among patients with CKD and hypertension without diabetes, targeting an SBP<120 mm Hg compared with <140 mm Hg reduced rates of major cardiovascular events and all-cause death without evidence of effect modifications by CKD or deleterious effect on the main kidney outcome.

Keywords: blood pressure; cardiovascular disease; chronic kidney disease; glomerular filtration rate; hypertension; mortality.

Figure 1.

Separation in achieved BP levels between the two intervention groups in the SPRINT participants with CKD. The broken line and open circles denote the intensive group; the solid line and closed circles denote the standard group. Vertical bars show 95% CIs for the mean at each time point.

Figure 2.

Kaplan-Meier curves for pre-specified outcomes in SPRINT participants with CKD. Panel A shows the primary cardiovascular outcome, defined as the composite of myocardial infarction, acute coronary syndrome, stroke, acute decompensated heart failure, and death from cardiovascular causes. Panel B shows the all-cause death outcome. Panel C shows the main kidney outcome, defined as the composite of a decrease in eGFR of ≥50% from baseline (confirmed by repeat testing ≥90 days later) or the development of ESRD. The broken lines depict the intensive group; the solid lines depict the standard group.

Figure 3.

Two phases of eGFR changes during follow-up in the SPRINT participants with CKD. The rate of change in eGFR using the values at 6 months after randomization as the baseline was −0.47 ml/min per 1.73 m² per year in the intensive group (broken line and triangles) and −0.32 ml/min per 1.73 m² per year in the standard group (solid line and circles; P=0.03). Open symbols denote fasting visits; closed symbols denote nonfasting visits.

Figure 4.

Urinary albumin-to-creatinine ratio (UACR) in the SPRINT participants with CKD. Geometric mean ratios of postrandomization to baseline UACR with 95% CIs. The broken line and open circles depict the intensive treatment group; the solid line and closed circles depict the standard treatment group. The horizontal line at 1.0 depicts equality of means (i.e., no change in UACR).