Even when ambulatory blood pressure (BP) is at goal, the absence of nocturnal dipping is associated with increased cardiovascular and kidney risks in patients with chronic kidney disease (CKD), reports a study in the American Journal of Kidney Diseases.
The prospective cohort study included 906 patients with stage 2 to stage 5 CKD seen at three Italian nephrology clinics. All had hypertension, defined as an office BP of 140/90 mm Hg or higher, or use of anti-hypertensive medications at any level of BP. The mean age was 64 years, and 61% of patients were men. Approximately 26% of patients had diabetes; the mean estimated glomerular filtration rate was 41 mL/min/1.73 m2.
Patients were classified into four groups, based on systolic ambulatory BP levels at or above goal, defined as systolic BP (SBP) less than 135 and nocturnal SBP less than 120 mm Hg, and the presence or absence of nocturnal dipping, defined as a nighttime-to-daytime SBP cutoff of 0.9. Overall, 49.1% of patients had ambulatory BP above goal without nocturnal dipping, 11.8% had ambulatory BP above goal with nocturnal dipping, 20.5% had ambulatory BP at goal without nocturnal dipping, and 18.6% had ambulatory BP at goal with nocturnal dipping.
On multivariable analysis, patients with ambulatory BP above goal were at increased risk of cardiovascular events, both without dipping (hazard ratio [HR], 2.79) and with dipping (HR, 2.05). Analysis of kidney disease progression showed a similar pattern: HR, 2.40 and 2.11, respectively. Patients who had ambulatory BP at goal but without dipping were also at increased risk: HR of 2.06 for cardiovascular events and HR of 1.82 for kidney disease progression compared with patients at goal and with nocturnal dipping.
The study is one of the first to analyze the combined prognostic effects of ambulatory BP and nocturnal dipping among patients with CKD. The results show increased cardiovascular and kidney disease risk for patients with CKD with ambulatory BP above goal, regardless of nocturnal dipping status.
For patients with ambulatory BP at goal, the absence of nocturnal dipping is a risk factor for both adverse cardiovascular and renal outcomes. The investigators concluded: “Our results confirm the essential role of ambulatory BP measurement to define accurately the hypertensive burden and circadian BP profile, thus allowing better risk stratification in these high-risk patients” [Borrelli S, et al. Dipping status, ambulatory blood pressure control, cardiovascular disease, and kidney disease progression: A multicenter cohort study of CKD. Am J Kidney Dis, published online ahead of print June 13, 2022. doi: 10.1053/j.ajkd.2022.04.010; https://www.ajkd.org/article/S0272-6386(22)00709-0/fulltext].