Study: Pulse Pressure Could Serve as Predictive Marker for CKD Progression

Pulse pressure was found to have a significant association with chronic kidney disease (CKD), suggesting that providers could use changes in pulse pressure could as a predictive marker for disease progression, according to a recent study.

The large-scale observational analysis, published in Scientific Reports, clarifies the relationship between pulse pressure and CKD progression and demonstrates the superior predictive value that pulse pressure provides compared with blood pressure measurements.

CKD is known to have a significant link to cardiovascular disease and mortality as well as tremendous health care costs. For some conditions, high blood pressure, hyperglycemia, and smoking are thought to be risk factors for CKD progression. Currently, systolic blood pressure (SBP) and diastolic blood pressure (DBP) are used as established prognostic factors for CKD progression. Pulse pressure, which is calculated by subtracting DBP from SBP, is a potential marker for cardiovascular disease, heart failure, and stroke, but few studies have investigated whether pulse pressure would be a risk factor for CKD progression.

Between 2008 and 2018, the investigators collected health check-up data from a population-based cohort study of patients with CKD from Iki Island in the Nagasaki Prefecture of Japan. Out of the 8029 patients that underwent annual health check-ups, 1042 were included in the study. The mean (SD) age of the patients was 64.5 (7.1) years and 51.6% of the cohort was male.

The patients were sectioned into 4 quartiles based on their pulse pressure at baseline:

• Q1, 48 mmHg or less (n = 278; 26.7%)
• Q2, between 49 and 56 mmHg (n = 260; 25.0%)
• Q3, between 57 and 65 mmHg (n = 245; 23.5%)
• Q4, between 66 or more mmHg (n = 259; 24.9%)

During a mean follow-up period of 4.66 years (4855 person-years), 241 cases of CKD progression occurred, representing an incident rate of 49.8 cases per 1000 person-years. There was a significant increase in CKD progression per 10 mmHg of pulse pressure, even after the investigators adjusted for confounding variables (adjusted HR [aHR], 1.17; P < .001). For each pulse pressure category, the incidence rates per 1000 person-years amounted to 31.9 for Q1, 40.5 for Q2, 47.2 for Q3, and 90.1 for Q4. The crude HR of CKD progressed increasingly with larger pulse pressures (Q2, 1.27; Q3, 1.47; Q4, 2.72; P < .001).

Similar results were observed after controlling for age, sex, blood pressure medications, diabetes, dyslipidemia, hyperuricemia, obesity, smoking, drinking, hemoglobin, baseline kidney filtration rate, and proteinuria (P = .003). A significant interaction between pulse pressure and baseline CKD (P = .022) or baseline urinary protein (P = .048).

To help explain the association, the investigators said that it’s possible that individuals with a high pulse pressure might have stiff vessels that may lead to microvascular kidney disease or that patients’ blood pressure may be uncontrolled as a result of low DBP.

“The kidney is a highly perfused organ with low resistance. As aortic stiffness increases, indicated by increased PP, the kidney experiences greater pressure fluctuation and wave reflection, which leads to excessive pressure and flow pulsatility into the microvascular bed of the kidneys. Kidney arteries are subjected to high pulsate circumferential stress and high longitudinal shear stress, which might cause microvascular ischemia and renal tissue damage,” wrote the investigators.

The study had several limitations, including that a causal relationship between pulse pressure and CKD progression could not be observed because of the observational design of the analysis. Additionally, the finding may have been impacted by selection bias, different sphygmomanometers were used, and data limitations may have prevented the ability to determine whether competing risks, such as death, were related.

Reference

Maeda T, Yokota S, Nishi T, et al. Association between pulse pressure and progression of chronic kidney disease. Sci Rep. December 2, 2021;11:23275. doi: 10.1038/s41598-021-02809-8