Introduction
24-hour dynamic blood pressure monitoring (ABPM) measurement of short-term blood pressure variability (BPV) has become an important indicator for predicting adverse cardiovascular events or mortality in patients. Short-term BPV elevations are associated with microvascular damage, subclinical organ damage to the heart, blood vessels and kidneys, and are independent of the mean of 24h blood pressure. At present, whether short-term BPV can further improve its risk prediction ability based on the mean of 24h blood pressure; and the predictive value of traditional risk factors for cardiovascular disease (CVD) is still controversial. In particular, longitudinal studies that evaluate the correlation between short-term BPV and impaired renal function are relatively limited. Most previous studies have focused on the discussion of the correlation between long-term BPV and renal outcomes. In addition, there are no valid indicators available to date for risk stratification of chronic kidney disease (CKD) events in patients with hypertension and .
Recently, a study published in the journal American Journal of Kidney Diseases discussed the correlation between short-term BPV and kidney disease.
Study Design
Methods
This is a prospective, observational cohort study. A total of 1,173 hypertensive patients from the Center for Etiology of Cardiovascular and Metabolic Diseases (CMERC-HI) were included in the study (having taken antihypertensive drugs or dynamic blood pressure ≥130/80mmHg, and the baseline estimated glomerular filtration rate [eGFR] ≥60mL/min/1.73㎡).
Blood pressure assessment
Dynamic blood pressure was monitored every 30 minutes using the Takeda TM-2430 device, with short-term BPV defined as mean actual variability (ARV) (average of differences between consecutive readings). Other indicators of short-term BPV include the standard deviation of blood pressure (SD) within 24h and the coefficient of variation of (CV, 24h blood pressure SD/24h mean blood pressure). To test the correlation between BPV and study results, ARVs, SDs, and CVs of systolic and diastolic blood pressure were measured and analyzed as continuous variable or tertile.
main endpoint
study main endpoint is the occurrence of renal compound events, including the continuous decrease of eGFR from the baseline level by at least 30% (two or more times, with at least 3 months apart); eGFR <60>300mg/g). EGFR assessment is performed every 3 months. Renal events were determined based on laboratory test results during follow-up.
Secondary analysis
1) Analyze the correlation between study outcomes and BPVs surrogate indicators - SD, CV; 2) Test the relationship between study outcomes and dipper blood pressure rhythm to further evaluate the relationship between differences in ABPM changes and study results; 3) Subgroup analysis, stratified analysis of age (<60>
Research Results
Results
Results
After 5.4 years of follow-up, 271 renal compound endpoint events occurred (46.5/1000 person-years). Multivariable Cox analysis showed that SBP-ARV and DBP-ARV in the highest quantile had a higher risk of nephropathy compound endpoint than the lowest quantile and were independent of 24hSBP or DBP [SBP-ARV hazard ratio (HR): 1.64, 95%CI, 1.16-2.33; DBP-ARV HR: 1.60, 95%CI, 1.15-2.24]. This correlation is consistent with the continuous variable analysis (1.0 per increase in SBP-ARV, HR: 1.03, 95% CI, 1.01-1.06; 1.01-1.06 for each increase in DBP-ARV, HR: 1.04; 95% CI, 1.01-1.08). SBP-ARV and DBP-ARV were associated with increased risk of CKD, which was independent of age, gender, 24hSBP or DBP, and microalbuminuria. And other short-term BPV indicators including SD, CV and dipper blood pressure rhythm were not significantly correlated with the occurrence of CKD.
Discussion
Discussion
This cohort study found that short-term BPV is related to renal compound endpoint events in patients with hypertension. At present, the scientific community knows little about its mechanism, which may be increased arterial stiffness and short-term BPV, both of which have reduced stress receptor sensitivity or sympathetic nervous system activation pathology characteristics, resulting in damage to the target organ (including decreased renal function).
In short, since hypertension is a high-risk group for the development of CKD, the findings of this study help to identify patients with hypertension who are prone to development of CKD in the early stage, can prevent adverse future outcomes and achieve early intervention.
References:
Jong Hyun Jhee, Sungha Park, Tae-Hyun Yoo, et al.Short-term Blood Pressure Variability and Incident CKD in Patients With Hypertension: Findings From the Cardiovascular and Metabolic Disease Etiology Research Center–High Risk (CMERC-HI) Study.American Journal of Kidney Diseases.2022.
