Association of ambulatory blood pressure monitoring with renal outcome in patients with chronic kidney disease

The association of time-updated ambulatory blood pressure and renal progression in hypertensive patients with chronic kidney disease: post hoc analysis of ACCURATE study

OBJECTIVES

: This study aimed to evaluate the effect of time-updated ambulatory blood pressure on chronic kidney disease (CKD) progression in patients with hypertension.

METHODS

: Among patients with hypertension and CKD stages 3 and 4, enrolled in a clinical trial in which hypertension was treated based on office or ambulatory blood pressure (BP), participants assigned to the ambulatory BP were included in this study. Ambulatory BP was measured at the start of the study and 3, 6, and 18 months. Renal events were defined as a decrease in the estimated glomerular filtration rate (eGFR) by at least 30%, dialysis, or transplantation.

RESULTS

: A total of 21 cases of renal events were observed. For baseline BP, a multivariate Cox model revealed that neither office SBP nor any component of ambulatory SBP, including mean, day-time, night-time BPs was associated with the risk of renal events. For time-updated BP, a marginal structural model revealed that the office SBP was not associated with renal events [hazard ratio 1.03, 95% confidence interval (CI) 0.99-1.07, P  = 0.117], but higher ambulatory SBPs, including day-time (hazard ratio 1.05, 95% CI 1.01-1.10, P  = 0.014), night-time (hazard ratio 1.05, 95% CI 1.02-1.08, P  = 0.001), and mean (hazard ratio 1.06, 95% CI 1.02-1.10, P  = 0.002) ambulatory SBPs, were significantly associated with an increased risk of renal events.

CONCLUSION

: A higher time-updated ambulatory BP was associated with an increased risk of renal events in patients with hypertension and CKD, whereas baseline office and ambulatory BP, and time-updated office BP were not.

Nocturnal systolic blood pressure dipping and progression of chronic kidney disease

The relationship between declining nocturnal blood pressure (BP) and adverse cardiovascular outcomes is well-recognized. However, the relationship between diurnal BP profile and the risk of chronic kidney disease (CKD) progression is unclear. Herein, we examined the association between nocturnal systolic SBP (SBP) dipping and CKD progression in 1061 participants at the Cardiovascular and Metabolic Disease Etiology Research Center-High Risk (CMERC-HI). The main exposure was diurnal systolic BP (SBP) profile and diurnal SBP difference ([nighttime SBP-daytime SBP] × 100/daytime SBP). The primary outcome was CKD progression, defined as a composite of ≥ a 50% decline in the estimated glomerular filtration rate from baseline or the initiation of kidney replacement therapy. During 4749 person-years of follow-up (median, 4.8 years), the composite outcome occurred in 380 (35.8%) participants. Compared to dippers, the hazard ratios (HRs) for the risk of adverse kidney outcomes were 1.02 (95% confidence interval [CI], 0.64-1.62), 1.30 (95% CI, 1.02-1.66), and 1.40 (95% CI, 1.03-1.90) for extreme dipper, non-dipper, and reverse dipper, respectively. In a continuous modeling, a 10% increase in diurnal SBP difference was associated with a 1.21-fold (95% CI, 1.07-1.37) higher risk of CKD progression. Thus, decreased nocturnal SBP decline was associated with adverse kidney outcomes in patients with CKD. Particularly, patients with non-dipping and reverse dipping patterns were at higher risk for CKD progression than those with a dipping pattern.

Diagnosis and treatment of hypertension in dialysis patients: a systematic review

In patients with end-stage renal disease (ESRD) undergoing dialysis, hypertension is common but often inadequately controlled. The prevalence of hypertension varies widely among studies because of differences in the definition of hypertension and the methods of used to measure blood pressure (BP), i.e., peri-dialysis or ambulatory BP monitoring (ABPM). Recently, ABPM has become the gold standard for diagnosing hypertension in dialysis patients. Home BP monitoring can also be a good alternative to ABPM, emphasizing BP measurement outside the hemodialysis (HD) unit. One thing for sure is pre- and post-dialysis BP measurements should not be used alone to diagnose and manage hypertension in dialysis patients. The exact target of BP and the relationship between BP and all-cause mortality or cause-specific mortality are unclear in this population. Many observational studies with HD cohorts have almost universally reported a U-shaped or even an L-shaped association between BP and all-cause mortality, but most of these data are based on the BP measured in HD units. Some data with ABPM have shown a linear association between BP and mortality even in HD patients, similar to the general population. Supporting this, the results of meta-analysis have shown a clear benefit of BP reduction in HD patients. Therefore, further research is needed to determine the optimal target BP in the dialysis population, and for now, an individualized approach is appropriate, with particular emphasis on avoiding excessively low BP. Maintaining euvolemia is of paramount importance for BP control in dialysis patients. Patient heterogeneity and the lack of comparative evidence preclude the recommendation of one class of medication over another for all patients. Recently, however, β-blockers could be considered as a first-line therapy in dialysis patients, as they can reduce sympathetic overactivity and left ventricular hypertrophy, which contribute to the high incidence of arrhythmias and sudden cardiac death. Several studies with mineralocorticoid receptor antagonists have also reported promising results in reducing mortality in dialysis patients. However, safety issues such as hyperkalemia or hypotension should be further evaluated before their use.

Short-term blood pressure variability as a potential therapeutic target for kidney disease

Short-term blood pressure variability (BPV) measured with ambulatory blood pressure (BP) monitoring has been demonstrated to be significant in predicting various clinical outcomes. Short-term BPV is distinguished from long-term BPV based on the time interval in which BP fluctuations are measured. Increased short-term BPV has been linked to detrimental effects on the microvascular structure and contributes to subclinical organ damage in the heart, blood vessels, and kidneys, regardless of the average 24-h BP levels. Short-term BPV can be defined by various measures, including calculated metrics (standard deviation, coefficient of variation, average real variability, weighted standard deviation, variability independent of the mean) or dipping patterns. Nevertheless, the additional role of short-term BPV beyond the predictive value of average 24-h BPs or established risk factors for cardiovascular disease and kidney disease remains unclear. In particular, longitudinal studies that evaluate the association between short-term BPV and kidney function impairment are limited and no conclusive data exist regarding which short-term BPV indicators most accurately reflect the prognosis of kidney disease. The issue of how to treat BPV in clinical practice is another concern that is frequently raised. This paper presents a review of the evidence for the prognostic role of short-term BPV in kidney outcomes. Additionally, this review discusses the remaining concerns about short-term BPV that need to be further investigated as an independent risk modifier.

Risk improvement and adverse kidney outcomes in patients with chronic kidney disease: findings from KNOW-CKD

BACKGROUND

Many trials have attempted to slow the progression of chronic kidney disease (CKD) by modifying specific risk factors, but without achieving satisfactory results. We aimed to evaluate the association between the degree of improvement in multiple risk factors and adverse kidney outcomes.

METHODS

This was a prospective observational study of 839 patients with CKD G3-G4. The main predictors were the number of improved risk factors between baseline and year one as follows: a decrease in proteinuria, systolic blood pressure, phosphate, and uric acid, and an increase in hemoglobin and bicarbonate from the baseline status to out of the target range. The primary outcome was a composite one, including CKD progression (50% decline in eGFR or kidney replacement therapy) and all-cause death.

RESULTS

Patients whose risk factors eventually improved had more unfavorable baseline profiles of the six considered factors. During 3097.8 person-years of follow-up (median 3.5 years per patient), the composite outcome occurred in 48.0% of patients (incidence rate, 13.0 per 100 person-years). Compared with an improvement of no risk factors, the adjusted HRs (95% CI) for improvement of 1 and ≥ 2 risk factors were 0.96 (0.76-1.22) and 0.53 (0.37-0.75), respectively. The association was not affected by diabetic status or CKD severity. Among the risk factors, proteinuria accounted for the greatest contribution to CKD progression.

CONCLUSIONS

In patients with CKD G3-G4, improvement in multiple factors was associated with a decreased risk of CKD progression, suggesting the importance of multifactorial risk management.

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

RATIONALE & OBJECTIVE

The association between short-term blood pressure variability (BPV) and kidney outcomes is poorly understood. This study evaluated the association between short-term BPV and kidney disease outcomes in people with hypertension.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

1,173 hypertensive participants in the Cardiovascular and Metabolic Disease Etiology Research Center-High Risk (2013-2018) Study with estimated glomerular filtration rate (eGFR) ≥60mL/min/1.73m².

EXPOSURE

Short-term BPV assessed by average real variability (ARV).

OUTCOME

Composite kidney disease outcome (30% decline in eGFR from baseline, new occurrence of eGFR <60mL/min/1.73m², or onset of UACR >300mg/g).

ANALYTICAL APPROACH

Multivariable Cox regression analyses to evaluate the association between systolic and diastolic BP ARV (SBP-ARV and DBP-ARV) and outcomes.

RESULTS

During a median follow-up of 5.4 [4.1-6.5] years, 271 events of the composite kidney disease outcome occurred (46.5 per 1,000 person-years). Multivariable Cox analysis revealed that the highest SBP-ARV and DBP-ARV tertiles were associated with a higher risk of the composite kidney disease outcome than the lowest tertiles, independent of the 24-hour SBP or DBP levels (HR, 1.64 [95% CI, 1.16-2.33], and 1.60 [95% CI, 1.15-2.24] for SBP-ARV and DBP-ARV, respectively). These associations were consistent when SBP-ARV and DBP-ARV were treated as continuous variables (HR per 1.0-unit greater SBP-ARV, 1.03 [95% CI, 1.01-1.06]; HR per 1.0-unit greater DBP-ARV, 1.04 [95% CI, 1.01-1.08]). These associations were consistent, irrespective of subgroups (age, sex, 24-hour SBP or DBP, and moderate albuminuria). However, other measures of short-term BPV including SD, coefficient of variation, and dipping patterns were not associated with the composite kidney disease outcome.

LIMITATIONS

Observational study design, the use of single measurement of 24-hour BP, lack of information on changes in antihypertensive medication during the follow-up.

CONCLUSIONS

Short-term BPV is associated with the development of a composite kidney disease outcome in hypertensive patients.

Blood Pressure and Chronic Kidney Disease Progression: An Updated Review

Hypertension (HTN) is common in chronic kidney disease (CKD), and it may aggravate CKD progression. The optimal blood pressure (BP) value in CKD patients is not established yet, although systolic BP ≤130 mmHg is acceptable as a target. Continuous BP monitoring is essential to detect the different variants of high BP and monitor the treatment response. Various methods of BP measurement in the clinic office and at home are currently used. One of these methods is ambulatory BP monitoring (ABPM), by which BP can be closely assessed for even diurnal changes.

We conducted a non-systematic literature review to explore and update the association between high BP and the course of CKD and to review various BP monitoring methods to determine the optimal method for BP recording in CKD patients. PubMed, EMBASE, Google, Google Scholar, and Web Science were searched for published reviews and original articles on BP and CKD by using various phrases and keywords such as "hypertension and CKD", "CKD progression and hypertension", "CKD stage and hypertension", "BP control in CKD", "BP measurement methods", "diurnal BP variation effect on CKD progression", and "types of hypertension." We evaluated and discussed published articles relevant to the review objective. Before preparing the final draft of this article, each author was assigned a section of the topic to read, research deeply, and write a summary about the assigned section. Then a summary of each author's contribution was collected and discussed in several group sessions.

Early detection of high BP is essential to prevent CKD development and progression. Although the latest Kidney Disease Improving Global Outcomes (KDIGO) guidelines suggest that a systolic BP ≤120 mmHg is the target toprevent CKD progression, systolic BP ≤130 mmHg is universally recommended.ABPM is a promising method to diagnose and follow up on BP control; however, the high cost of the new devices and patient unfamiliarity with them have proven to be major disadvantages with regard to this method.

Association Between Longitudinal Blood Pressure Trajectory and the Progression of Chronic Kidney Disease: Results From the KNOW-CKD

Studies on the longitudinal temporal trend of blood pressure (BP) and its impact on kidney function are scarce. Here, we evaluated the association of dynamic changes in systolic blood pressure (SBP) over time with adverse kidney outcomes. We analyzed 1837 participants from the KNOW-CKD (Korean Cohort Study for Outcomes in Patients With Chronic Kidney Disease). The main exposure was 3 distinct SBP trajectories determined by the latent class mixed model (decreasing, stable, and increasing) using 3 SBP measurements at 0, 6, and 12 months. The primary outcome was CKD progression, defined as a composite of halving estimated glomerular filtration rate from baseline value or onset of end-stage kidney disease. SBP declined from 144 to 120 mm Hg in the decreasing SBP trajectory group and rose from 114 to 136 mm Hg in the increasing trajectory group within 1 year. During 6576 person-years of follow-up (median, 3.7 years), the composite outcome occurred in 521 (28.4%) participants. There were fewer primary outcome events in the decreasing (30.6%) and stable (26.5%) SBP trajectory groups than in the increasing trajectory group (33.0%). In the multivariable-adjusted cause-specific hazards model, increasing SBP trajectory was associated with a 1.28-fold higher risk for adverse kidney outcome compared with stable SBP trajectory. However, the risk for the primary outcome did not differ between the decreasing and stable SBP trajectory groups. In this longitudinal CKD cohort study, compared with stable SBP trajectory, increasing SBP trajectory was associated with higher risk for adverse kidney outcome, whereas decreasing SBP trajectory showed similar risk.

How important is dietary management in chronic kidney disease progression? A role for low protein diets

High dietary protein intake may lead to increased intraglomerular pressure and glomerular hyperfiltration, which in the long-term can lead to de novo or aggravating preexisting chronic kidney disease (CKD). Hence, a low protein diet (LPD, 0.6 to 0.8 g/kg/day) is recommended for the management of CKD. There are evidences that dietary protein restriction mitigate progression of CKD and retard the initiation of dialysis or facilitate incremental dialysis. LPD is also helpful to control metabolic derangements in CKD such as metabolic acidosis and hyperphosphatemia. Recently, a growing body of evidence has emerged on the benefits of plant-dominant low-protein diet (PLADO), which composed of > 50% plant-based sources. PLADO is considered to be helpful for relieving uremic burden and metabolic complications in CKD compared to animal protein dominant consumption. It may also lead to favorable alterations in the gut microbiome, which can modulate uremic toxin generation along with reducing cardiovascular risk. Alleviation of constipation in PLADO may minimize the risk of hyperkalemia. A balanced and individualized dietary approach for good adherence to LPD utilizing various plant-based sources as patients' preference should be elaborated for the optimal care in CKD. Periodic nutritional assessment under supervision of trained dietitians should be warranted to avoid protein-energy wasting.

Blood pressure control in patients with chronic kidney disease

Uncontrolled blood pressure (BP) in patients with chronic kidney disease (CKD) can lead to serious adverse outcomes. To prevent the occurrence of cardiovascular events (CVEs), and end-stage kidney disease, achieving an optimal BP level is important. Recently, there has been a paradigm shift in the management of BP largely as a result of the Systolic Blood Pressure Intervention Trial (SPRINT), which showed a reduction in CVEs by lowering systolic BP to 120 mmHg. A lower systolic blood pressure (SBP) target has been accepted by the Kidney Disease: Improving Global Outcomes (KDIGO) 2021 guidelines. However, whether intensive control of SBP targeting < 120 mmHg is also effective in patients with CKD is controversial. Notably, this lower target SBP is associated with a higher risk of adverse kidney outcomes. Unfortunately, there have been no randomized controlled trials on this issue involving only patients with CKD, particularly those with advanced CKD. In this review, we discuss the optimal control of BP in patients with CKD in terms of reduction in death and CVEs as well as attenuation of CKD progression based on the evidence-based literature.

Clinical significance of heart rate variability for the monitoring of cardiac autonomic neuropathy in end-stage renal disease patients

BACKGROUND AND AIMS

The aim of this study is to determine whether the measurement of continuous heart rate variability (HRV) is useful in the evaluation of cardiac autonomic neuropathy (CAN) in end-stage renal disease (ESRD) patients.

METHODS AND RESULTS

This cross-sectional study was performed at Seoul St. Mary's hospital between June 2017 and February 2018. Seventy-seven ESRD patients, and 29 healthy controls (HCs) were asked to wear a continuous ambulatory HRV monitor for 24 h. General cardiac function was evaluated using transthoracic echocardiogram (TTE), pulse wave velocity (PWV), coronary calcium scoring (CCS), and 24-h ambulatory blood pressure monitoring (ABPM). HRV parameters of ESRD patients and HCs, and the correlation of HRV parameters with cardiovascular screening methods were observed. All HRV parameters were significantly decreased in ESRD patients compared to HCs (P < 0.001). In the correlation analysis between TTE results and HRV parameters, 24-h standard deviation of all N-N intervals (24SDNN), 24-h standard deviation of sequential 5-min N-N interval means (24DANN) and Low Frequency Power/High Frequency Power (LF/HF) ratio showed negative correlations with E/e', LAVI and TR velocity which are representative indices for the diastolic function of the heart (P < 0.05). HRV parameters showed negative correlations with baPWV, CCS, and 24-h ABPM results as well (P < 0.05). Hemoglobin and serum albumin showed positive correlations with HRV parameters, and glucose, BUN, creatinine, and iPTH levels showed negative correlations (P < 0.05).

CONCLUSION

Continuous HRV monitoring may be a useful tool for the evaluation of CAN in ESRD.