Different components of blood pressure are associated with increased risk of atherosclerotic cardiovascular disease versus heart failure in advanced chronic kidney disease

Heart failure with preserved ejection fraction in haemodialysis patients: prevalence, diagnosis, risk factors, prognosis

AIMS

Heart failure (HF) is a common complication and the leading cause of mortality in maintenance haemodialysis (MHD) patients. Few studies have investigated heart failure with preserved ejection fraction (HFpEF), which is known to affect a majority of patients. The objective of this study is to explore the prevalence, clinical profiles, diagnosis, risk factors and prognosis of MHD patients with HFpEF.

METHODS AND RESULTS

Four hundred thirty-nine patients haemodialyzsed for over 3 months were enrolled in the study and evaluated for HF according to the European Society of Cardiology guidelines. Clinical and laboratory parameters were recorded at baseline. The median follow-up of the study was 22.5 months. A total of 111 (25.3%) MHD patients were diagnosed with HF, while 94 (84.7%) of the HF patients were classified into HFpEF. The cut-off value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) was 4922.5 pg/mL for predicting HFpEF (sensitivity 0.840, specificity 0.723, AUC 0.866) in MHD patients. Age, diabetes mellitus, coronary artery disease and serum phosphorus were independent risk factors for the incidence of HFpEF in MHD patients while normal urine volume, haemoglobin, serum iron and serum sodium were protective factors. MHD patients with HFpEF had a higher risk of all-cause mortality than those without HF (hazard ratio 2.47, 95% confidence interval 1.55-3.91, P < 0.0001).

CONCLUSIONS

The majority of MHD patients with HF were categorized into HFpEF, with a poor long-term survival rate. NT-proBNP beyond 4922.5 pg/mL performed well in the prediction of HFpEF in MHD patients.

Blood pressure and kidney outcomes in patients with severely decreased glomerular filtration rate: a nationwide observational cohort study

OBJECTIVES

To investigate the association between blood pressure (BP) and kidney outcomes in patients with estimated glomerular filtration rate less than 30 ml/min per 1.73 m 2 and different degrees of albuminuria.

METHODS

National observational cohort study of 18 071 chronic kidney disease (CKD) stage 4-5 patients in routine nephrology care 2010-2017. The association between both baseline and repeated clinic office BP and eGFR slope and kidney replacement therapy (KRT) was explored using multivariable adjusted joint models. The analyses were stratified on albuminuria at baseline.

RESULTS

The adjusted yearly eGFR slope became increasingly steeper from -0,91 (95% CI -0.83 to -1.05) ml/min per 1.73 m 2 per year in those with SBP less than 120 mmHg at baseline to -2.09 (-1.83 to -2.37) ml/min per 1.73 m 2 in those with BP greater than 160 mmHg. Similarly, eGFR slope was steeper with higher DBP. Lower SBP and DBP was associated with slower eGFR decline in patients with albuminuria grade A3 (>30 mg/mmol) but not consistently in albuminuria A1-A2. Those with diabetes progressed faster and the association between BP and eGFR slope was stronger. In repeated BP measurement analyses, every 10 mmHg higher SBP over time was associated with 39% additional risk of KRT.

CONCLUSION

In people with eGFR less than 30 ml/min per 1.73 m 2 , lower clinic office BP is associated with more favorable kidney outcomes. Our results support lower BP targets also in people with CKD stage 4-5.

Factors associated with aortic valve stenosis in Japanese patients with end-stage kidney disease

Background

Aortic valve stenosis (AS) has a high prevalence and poor prognosis in patients who receive maintenance dialysis. However, few large-scale observational studies in Japan have investigated patients with AS who underwent dialysis. In this study, we investigated the prevalence and factors associated with AS in Japanese patients who underwent dialysis.

Methods

In this cross-sectional analysis, we enrolled patients who underwent dialysis and transthoracic echocardiography between July 1, 2017 and June 30, 2018. Patients with a maximum aortic jet velocity (Vmax) ≥ 2.0 m/s, pressure gradient (PG) between the left ventricle and ascending aorta (mean PG) ≥ 20 mmHg, or aortic valve area (AVA) ≤ 1.0 cm² were categorized into the AS group (G1). Patients with Vmax ≥ 3.0 m/s, mean PG ≥ 20 mmHg, or AVA ≤ 1.0 cm² were categorized into the moderate and severe AS groups (G2). We performed multivariate logistic regression analysis and compared G1 and G2 with the non-AS group to determine the risk factors for AS. We also investigated the risk factors for aortic valve calcification, which is a pre-stage for AS.

Results

Of the 2,786 patients investigated, 555 (20.0%) and 193 (6.9%) were categorized into G1 and G2, respectively. Multivariate logistic regression analysis revealed that age, long-term dialysis, and elevated serum phosphorus levels were associated with AS in both the groups (p < 0.05). These factors were converted into ordinal categories, and a multivariate logistic regression analysis was performed. Patients with serum phosphorus levels measuring 5.0–5.9 mg/dL and > 6.0 mg/dL showed a higher risk of AS than those with serum phosphorus levels measuring < 4.0 mg/dL (odds ratio 2.24, p = 0.01 and odds ratio 2.66, p = 0.005, respectively). Aortic valve calcification was associated with age, long-term dialysis, diabetes mellitus, administration of vitamin D receptor activators, elevated serum calcium levels, and anemia (p < 0.05 for all).

Conclusions

Patients on dialysis showed a high prevalence of AS, which was associated with age, long-term dialysis, and elevated serum phosphorus levels.

Trial registration

UMIN000026756, registered on March 29, 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02758-y.

Time-specific associations of wearable sensor-based cardiovascular and behavioral readouts with disease phenotypes in the outpatient setting of the Chronic Renal Insufficiency Cohort

Patients with chronic kidney disease are at risk of developing cardiovascular disease. To facilitate out-of-clinic evaluation, we piloted wearable device-based analysis of heart rate variability and behavioral readouts in patients with chronic kidney disease from the Chronic Renal Insufficiency Cohort and controls (n  =  49). Time-specific partitioning of heart rate variability readouts confirm higher parasympathetic nervous activity during the night (mean RR at night 14.4  ±  1.9 ms vs. 12.8  ±  2.1 ms during active hours; n  =  47, analysis of variance (ANOVA) q  =  0.001). The α2 long-term fluctuations in the detrended fluctuation analysis, a parameter predictive of cardiovascular mortality, significantly differentiated between diabetic and nondiabetic patients (prominent at night with 0.58  ±  0.2 vs. 0.45  ±  0.12, respectively, adj. p  =  0.004). Both diabetic and nondiabetic chronic kidney disease patients showed loss of rhythmic organization compared to controls, with diabetic chronic kidney disease patients exhibiting deconsolidation of peak phases between their activity and standard deviation of interbeat intervals rhythms (mean phase difference chronic kidney disease 8.3 h, chronic kidney disease/type 2 diabetes mellitus 4 h, controls 6.8 h). This work provides a roadmap toward deriving actionable clinical insights from the data collected by wearable devices outside of highly controlled clinical environments.

Association of blood pressure after peritoneal dialysis initiation with the decline rate of residual kidney function in newly-initiated peritoneal dialysis patients

Background

Lower blood pressure (BP) levels are linked to a slower decline of kidney function in patients with chronic kidney disease (CKD) without kidney replacement therapy. However, there are limited data on this relation in peritoneal dialysis (PD) patients. Here we evaluated the association of BP levels with the decline of residual kidney function (RKF) in a retrospective cohort study.

Methods

We enrolled 228 patients whose PD was initiated between 1998 and 2014. RKF was measured as the average of creatinine and urea clearance in 24-hr urine collections. We calculated the annual decline rate of RKF by determining the regression line for individual patients. RKF is thought to decline exponentially, and thus we also calculated the annual decline rate of logarithmic scale of RKF (log RKF). We categorized the patients’ BP levels at 3 months after PD initiation (BP_3M) into four groups (Optimal, Normal & High normal, Grade 1 hypertension, Grade 2 & 3 hypertension) according to the 2018 European Society of Cardiology and European Society of Hypertension Guidelines for the management of arterial hypertension.

Results

The unadjusted, age- and sex-adjusted, and multivariable-adjusted decline rate of RKF and log RKF decreased significantly with higher BP_3M levels (P for trend <0.01). Compared to those of the Optimal group, the multivariable-adjusted odds ratios (95% confidence interval) for the faster side of the median decline rate of RKF and log RKF were 4.04 (1.24–13.2) and 5.50 (1.58–19.2) in the Grade 2 and 3 hypertension group, respectively (p<0.05).

Conclusions

Higher BP levels after PD initiation are associated with a faster decline in RKF among PD patients.

Sex Differences in Cardiovascular Outcomes in CKD: Findings From the CRIC Study

RATIONALE & OBJECTIVE

Cardiovascular events are less common in women than men in general populations; however, studies in chronic kidney disease (CKD) are less conclusive. We evaluated sex-related differences in cardiovascular events and death in adults with CKD.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

1,778 women and 2,161 men enrolled in the Chronic Renal Insufficiency Cohort (CRIC).

EXPOSURE

Sex (women vs men).

OUTCOME

Atherosclerotic composite outcome (myocardial infarction, stroke, or peripheral artery disease), incident heart failure, cardiovascular death, and all-cause death.

ANALYTICAL APPROACH

Cox proportional hazards regression.

RESULTS

During a median follow-up period of 9.6 years, we observed 698 atherosclerotic events (women, 264; men, 434), 762 heart failure events (women, 331; men, 431), 435 cardiovascular deaths (women, 163; men, 274), and 1,158 deaths from any cause (women, 449; men, 709). In analyses adjusted for sociodemographic, clinical, and metabolic parameters, women had a lower risk of atherosclerotic events (HR, 0.71 [95% CI, 0.57-0.88]), heart failure (HR, 0.76 [95% CI, 0.62-0.93]), cardiovascular death (HR, 0.55 [95% CI, 0.42-0.72]), and death from any cause (HR, 0.58 [95% CI, 0.49-0.69]) compared with men. These associations remained statistically significant after adjusting for cardiac and inflammation biomarkers.

LIMITATIONS

Assessment of sex hormones, which may play a role in cardiovascular risk, was not included.

CONCLUSIONS

In a large, diverse cohort of adults with CKD, compared with men, women had lower risks of cardiovascular events, cardiovascular mortality, and mortality from any cause. These differences were not explained by measured cardiovascular risk factors.

Impact of AKI on Urinary Protein Excretion: Analysis of Two Prospective Cohorts

BACKGROUND

Prior studies of adverse renal consequences of AKI have almost exclusively focused on eGFR changes. Less is known about potential effects of AKI on proteinuria, although proteinuria is perhaps the strongest risk factor for future loss of renal function.

METHODS

We studied enrollees from the Assessment, Serial Evaluation, and Subsequent Sequelae of AKI (ASSESS-AKI) study and the subset of the Chronic Renal Insufficiency Cohort (CRIC) study enrollees recruited from Kaiser Permanente Northern California. Both prospective cohort studies included annual ascertainment of urine protein-to-creatinine ratio, eGFR, BP, and medication use. For hospitalized participants, we used inpatient serum creatinine measurements obtained as part of clinical care to define an episode of AKI (i.e., peak/nadir inpatient serum creatinine ≥1.5). We performed mixed effects regression to examine change in log-transformed urine protein-to-creatinine ratio after AKI, controlling for time-updated covariates.

RESULTS

At cohort entry, median eGFR was 62.9 ml/min per 1.73 m² (interquartile range [IQR], 46.9-84.6) among 2048 eligible participants, and median urine protein-to-creatinine ratio was 0.12 g/g (IQR, 0.07-0.25). After enrollment, 324 participants experienced at least one episode of hospitalized AKI during 9271 person-years of follow-up; 50.3% of first AKI episodes were Kidney Disease Improving Global Outcomes stage 1 in severity, 23.8% were stage 2, and 25.9% were stage 3. In multivariable analysis, an episode of hospitalized AKI was independently associated with a 9% increase in the urine protein-to-creatinine ratio.

CONCLUSIONS

Our analysis of data from two prospective cohort studies found that hospitalization for an AKI episode was independently associated with subsequent worsening of proteinuria.

A lower blood pressure threshold to define hypertension: the effect on prevalence, control rate, and constituent ratio of systolic and/or diastolic hypertension

OBJECTIVE

To evaluate the impact of the new US hypertension criteria [systolic blood pressure/diastolic blood pressure (SBP/DBP ≥130/80 mmHg)] on hypertension prevalence and the constituent ratio of three hypertension phenotypes.

PARTICIPANTS AND METHODS

This study included 1185 adult participants, who received blood pressure (BP) measurements for 3 days over a 7-day period. At each visit, the BP was measured three times and the average was used as the final value. The criteria of hypertension were if the participant had received treatment with antihypertensive drugs for at least 2 weeks, or SBP/DBP of at least 140/90 mmHg (old criteria) or at least 130/80 mmHg (new criteria) for the untreated participants. The diagnosis of hypertension was made on the basis of first-day BP values (epidemiological method) or the average of the 3-day BP values (clinical method), respectively. The constituent ratios of isolated systolic, isolated diastolic, and systolic-diastolic hypertension were evaluated.

RESULTS

When using the old criteria, the overall epidemiological prevalence of hypertension was 41.1% and the overall clinical prevalence of hypertension was 34.8%. When using the new criteria, these values increased to 64.3 and 57.4%, respectively. Meanwhile, against the old criteria, the new criteria increased the constituent ratio of systolic-diastolic hypertension from 24.4 to 50.5% (P<0.001) for the epidemiological method and from 19.1 to 45.7% (P<0.001) for the clinical method in the newly diagnosed hypertensive patients.

CONCLUSION

The hypertension criteria of at least 130/80 mmHg not only significantly increased the clinical prevalence of hypertension, but significantly altered the constituent ratio of three hypertension phenotypes among the newly diagnosed hypertensive patients.

Evolution of Echocardiographic Measures of Cardiac Disease From CKD to ESRD and Risk of All-Cause Mortality: Findings From the CRIC Study

RATIONALE & OBJECTIVE

Abnormal cardiac structure and function are common in chronic kidney disease (CKD) and end-stage renal disease (ESRD) and linked with mortality and heart failure. We examined changes in echocardiographic measures during the transition from CKD to ESRD and their associations with post-ESRD mortality.

STUDY DESIGN

Prospective study.

SETTING & PARTICIPANTS

We studied 417 participants with CKD in the Chronic Renal Insufficiency Cohort (CRIC) who had research echocardiograms during CKD and ESRD.

PREDICTOR

We measured change in left ventricular mass index, left ventricular ejection fraction (LVEF), diastolic relaxation (normal, mildly abnormal, and moderately/severely abnormal), left ventricular end-systolic (LVESV), end-diastolic (LVEDV) volume, and left atrial volume from CKD to ESRD.

OUTCOMES

All-cause mortality after dialysis therapy initiation.

ANALYTICAL APPROACH

Cox proportional hazard models were used to test the association of change in each echocardiographic measure with postdialysis mortality.

RESULTS

Over a mean of 2.9 years between pre- and postdialysis echocardiograms, there was worsening of mean LVEF (52.5% to 48.6%; P<0.001) and LVESV (18.6 to 20.2mL/m2.7; P<0.001). During this time, there was improvement in left ventricular mass index (60.4 to 58.4g/m2.7; P=0.005) and diastolic relaxation (11.11% to 4.94% with moderately/severely abnormal; P=0.02). Changes in left atrial volume (4.09 to 4.15mL/m2; P=0.08) or LVEDV (38.6 to 38.4mL/m2.7; P=0.8) were not significant. Worsening from CKD to ESRD of LVEF (adjusted HR for every 1% decline in LVEF, 1.03; 95% CI, 1.00-1.06) and LVESV (adjusted HR for every 1mL/m2.7 increase, 1.04; 95% CI, 1.02-1.07) were independently associated with greater risk for postdialysis mortality.

LIMITATIONS

Some missing or technically inadequate echocardiograms.

CONCLUSIONS

In a longitudinal study of patients with CKD who subsequently initiated dialysis therapy, LVEF and LVESV worsened and were significantly associated with greater risk for postdialysis mortality. There may be opportunities for intervention during this transition period to improve outcomes.

Blood pressure components and incident cardiovascular disease and mortality events among Iranian adults with chronic kidney disease during over a decade long follow-up: a prospective cohort study

Background

To explore the association between systolic and diastolic blood pressure (SBP and DBP respectively) and pulse pressure (PP) with cardiovascular disease (CVD) and mortality events among Iranian patients with prevalent CKD.

Methods

Patients [n = 1448, mean age: 60.9 (9.9) years] defined as those with estimated glomerular filtration rate < 60 ml/min/1.73 m², were followed from 31 January 1999 to 20 March 2014. Multivariable Cox proportional hazard models were applied to examine the associations between different components of BP with outcomes.

Results

During a median follow-up of 13.9 years, 305 all-cause mortality and 317 (100 fatal) CVD events (among those free from CVD, n = 1232) occurred. For CVD and CV-mortality, SBP and PP showed a linear relationship, while a U-shaped relationship for DBP was observed with all outcomes. Considering 120 ≤ SBP < 130 as reference, SBP ≥ 140 mmHg was associated with the highest hazard ratio (HR) for CVD [1.68 (1.2–2.34)], all-cause [1.72 (1.19–2.48)], and CV-mortality events [2.21 (1.16–4.22)]. Regarding DBP, compared with 80 ≤ DBP < 85 as reference, the level of ≥ 85 mmHg increased risk of CVD and all-cause mortality events; furthermore, DBP < 80 mmHg was associated with significant HR for CVD events [1.55 (1.08–2.24)], all-cause [1.68 (1.13–2.5)] and CV-mortality events [3.0 (1.17–7.7)]. Considering PP, the highest HR was seen in participants in the 4th quartile for all outcomes of interest; HRs for CVD events [1.92 (1.33–2.78)], all-cause [1.71 (1.11–2.63)] and CV-mortality events [2.22 (1.06–4.64)].

Conclusions

Among patients with CKD, the lowest risk of all-cause and CV-mortality as well as incident CVD was observed in those with SBP < 140, 80 ≤ DBP < 85 and PP < 64 mmHg.

Synbiotic meal decreases uremic toxins in hemodialysis individuals: A placebo-controlled trial

Generation of uremic toxins p-cresylsulfate (p-CS), indoxyl sulfate (IS) and indole 3-acetic acid (IAA) in hemodialysis (HD) individuals may be associated with the gut flora and recognized markers of disease progression. This study investigated the effect of synbiotic meal on uremic toxins in HD individuals. We conducted randomized singleblind and placebo-controlled intervention study with 58 HD subjects (20F/38M, 63.1 ± 10.9-old) who were randomly allocated in synbiotic group (SG, 40 g of extruded sorghum plus 100 mL of unfermented probiotic milk) or control group (CG, 40 g of extruded corn plus 100 mL of pasteurized milk), during 7-wk Metabolic markers and uremic toxins, fecal concentration of short chain fatty acid and pH value was determined. The SG group had decreased serum p-CS and IS, as well as decreased urea concentration (p < .05) compared to CG. SG showed higher fecal butyric acid and lower pH compared to baseline and SC (p < .05). In addition, serum p-CS and fecal pH were positively correlated to urea concentration in SG participants at the endpoint. The consumption of the synbiotic meal during 7-wk reduced colonic pH, and reduced serum uremic (p-CS and IS) toxins and urea in HD subjects.

Blood pressure parameters and morbid and mortal outcomes in nondialysis-dependent chronic kidney disease

PURPOSE OF REVIEW

Observational and interventional studies provide conflicting evidence regarding optimal blood pressure (BP) control in persons with chronic kidney disease (CKD). Recent publications provide additional information to inform therapeutic decision-making.

RECENT FINDINGS

Targeting SBP to less than 120 mmHg, versus less than 140 mmHg, decreased cardiovascular events and all-cause mortality in persons with nondiabetic CKD. A meta-analysis of trials testing blood pressure management among nondialysis-dependent CKD patients (15 924 total patients) found more intensive therapies generally reduced mortality in all subgroups. Observational studies demonstrate that low SBP is associated with higher mortality in CKD. A recent report suggests that this is because of death from cardiovascular and noncardiovascular and nonmalignant causes, whereas higher BP is associated with death from cardiovascular causes. The shape of association between BP and cardiovascular and noncardiovascular events also appears to vary depending on baseline risk factors. Furthermore, BP measurement methodology may differ importantly between observational and interventional studies.

SUMMARY

We review and summarize observational and interventional literature relating BP parameters to key clinical outcomes in persons with CKD. Apart from the inherent differences between these study designs, the disparate findings from trials and observational studies may be because of differences in patient characteristics and BP measurement techniques.

Improving the prognosis of patients with severely decreased glomerular filtration rate (CKD G4+): conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Patients with severely decreased glomerular filtration rate (GFR) (i.e., chronic kidney disease [CKD] G4+) are at increased risk for kidney failure, cardiovascular disease (CVD) events (including heart failure), and death. However, little is known about the variability of outcomes and optimal therapeutic strategies, including initiation of kidney replacement therapy (KRT). Kidney Disease: Improving Global Outcomes (KDIGO) organized a Controversies Conference with an international expert group in December 2016 to address this gap in knowledge. In collaboration with the CKD Prognosis Consortium (CKD-PC) a global meta-analysis of cohort studies (n = 264,515 individuals with CKD G4+) was conducted to better understand the timing of clinical outcomes in patients with CKD G4+ and risk factors for different outcomes. The results confirmed the prognostic value of traditional CVD risk factors in individuals with severely decreased GFR, although the risk estimates vary for kidney and CVD outcomes. A 2- and 4-year model of the probability and timing of kidney failure requiring KRT was also developed. The implications of these findings for patient management were discussed in the context of published evidence under 4 key themes: management of CKD G4+, diagnostic and therapeutic challenges of heart failure, shared decision-making, and optimization of clinical trials in CKD G4+ patients. Participants concluded that variable prognosis of patients with advanced CKD mandates individualized, risk-based management, factoring in competing risks and patient preferences.

Central Blood Pressure and Cardiovascular Outcomes in Chronic Kidney Disease

BACKGROUND AND OBJECTIVES

Central BP measurements provide noninvasive measurement of aortic BP; our objectives were to examine the association of central and brachial BP measurements with risk of cardiovascular outcomes and mortality in patients with CKD and to determine the role of central BP measurement in conjunction with brachial BP in estimating cardiovascular risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a prospective, longitudinal study (the Chronic Renal Insufficiency Cohort), central BP was measured in participants with CKD using the SphygmoCorPVx System. Cox proportional hazards models were used for analyses.

RESULTS

Mean age of the participants (n=2875) was 60 years old. After a median follow-up of 5.5 years, participants in the highest quartile of brachial systolic BP (≥138 mm Hg) were at higher risk for the composite cardiovascular outcome (hazard ratio, 1.59; 95% confidence interval, 1.17 to 2.17; c statistic, 0.76) but not all-cause mortality (hazard ratio, 1.28; 95% confidence interval, 0.90 to 1.80) compared with those in the lowest quartile. Participants in the highest quartile of central systolic BP were also at higher risk for the composite cardiovascular outcome (hazard ratio, 1.69; 95% confidence interval, 1.24 to 2.31; c statistic, 0.76) compared with participants in the lowest quartile.

CONCLUSIONS

We show that elevated brachial and central BP measurements are both associated with higher risk of cardiovascular disease outcomes in patients with CKD. Measurement of central BP does not improve the ability to predict cardiovascular disease outcomes or mortality in patients with CKD compared with brachial BP measurement.

Longitudinal Blood Pressure in Late-Stage Chronic Kidney Disease and the Risk of End-Stage Kidney Disease or Mortality (Best Blood Pressure in Chronic Kidney Disease Study)

Whether different methods of quantitating blood pressure (BP) in late chronic kidney disease better mimic pathophysiological processes and clinical outcomes remains unclear. In a retrospective study, we determined the association of BP with end-stage kidney disease (ESKD) and all-cause mortality with BP modeled at baseline versus longitudinally with time-varying Cox models as (1) current (most recent) clinic visit, (2) lag (visit immediately preceding the current), (3) cumulative (average of previous measurements), and (4) change from baseline to the most recent. Among 1203 (6913 visits) study patients, the mean age and baseline estimated glomerular filtration rate were 66 and 18 mL·min −1 ·1.73 m −2 ), and 40% were female. Patients had a mean of 6.7 BP measurements, 540 (44.8%) reached ESKD, and 141 (11.7%) died. For systolic BP >160, current (hazard ratio [HR], 1.67), cumulative (HR, 1.58), and a rise to >160 from baseline 120 to 160 (HR, 1.60) were associated with ESKD. Similarly, diastolic BP >85 was associated with ESKD when modeled as current (HR, 1.47), lag (HR, 1.63), cumulative (HR, 2.15), or change from baseline (rise to >85 from a baseline of 60–85; HR, 1.62). Both low SBP (<120), when modeled as current (HR, 1.59), cumulative exposure (HR, 1.76), persistently <120 (HR, 2.28), and high SBP (>140), when modeled as cumulative exposure, were associated with all-cause mortality. For diastolic BP, only cumulative >85 was significantly associated with mortality (HR, 2.75). Thus, in late-stage chronic kidney disease, persistently high or rises in systolic BP or diastolic BP are associated with risk of ESKD, whereas baseline BP measures did not convey information on risk.

Blood Pressure Parameters and their Associations with Death in Patients with Chronic Kidney Disease

PURPOSE OF REVIEW

Optimal blood pressure (BP) parameters among patients with chronic kidney disease (CKD) have been a matter of debate. This review critically evaluates recent literature to better define the associations of BP parameters and death among individuals with non-dialysis-dependent CKD.

RECENT FINDINGS

Observational studies report a "U- or J-shaped" association between BP and all-cause mortality in CKD and caution-intensive BP lowering in the elderly. Causes of death have been evaluated in a recent report noting higher cardiovascular and non-cardiovascular/non-malignant-related mortality among CKD population with SBP < 110 and > 150 mmHg. Very few randomized control trials evaluated the impact of different BP targets on patient-centered outcomes in those with CKD. Recently published SPRINT trial results suggest that intensive SBP control (<120 mm Hg) reduces cardiovascular events and all-cause death among non-diabetic patients with and without CKD. Clinical trial evidence supports lower BP target in those with mild to moderate non-diabetic CKD. However, clinical trials are warranted to further determine the beneficial effects of intensive blood pressure control in diabetic CKD population. In elderly population with CKD, BP targets might need to be individualized based on their comorbidities, life expectancy, and other factors.

Blood Pressure and Risk of Cardiovascular Events in Patients on Chronic Hemodialysis: The CRIC Study (Chronic Renal Insufficiency Cohort)

We recently reported a linear association between higher systolic blood pressure (SBP) and risk of mortality in hemodialysis patients when SBP is measured outside of the dialysis unit (out-of-dialysis-unit-SBP), despite there being a U-shaped association between SBP measured at the dialysis unit (dialysis-unit-SBP) with risk of mortality. Here, we explored the relationship between SBP with cardiovascular events, which has important treatment implications but has not been well elucidated. Among 383 hemodialysis participants enrolled in the prospective CRIC study (Chronic Renal Insufficiency Cohort), multivariable splines and Cox models were used to study the association between SBP and adjudicated cardiovascular events (heart failure, myocardial infarction, ischemic stroke, and peripheral artery disease), controlling for differences in demographics, cardiovascular disease risk factors, and dialysis parameters. Dialysis-unit-SBP and out-of-dialysis-unit-SBP were modestly correlated (r=0.34; P<0.001). We noted a U-shaped association of dialysis-unit-SBP and risk of cardiovascular events, with the nadir risk between 140 and 170 mm Hg. In contrast, there was a linear stepwise association between out-of-dialysis-unit-SBP with risk of cardiovascular events. Participants with out-of-dialysis-unit-SBP ≥128 mm Hg (top 2 quartiles) had >2-fold increased risk of cardiovascular events compared with those with out-of-dialysis-unit-SBP ≤112 mm Hg (3rd SBP quartile: adjusted hazard ratio, 2.08 [95% confidence interval, 1.12-3.87] and fourth SBP quartile: adjusted hazard ratio, 2.76 [95% confidence interval, 1.42-5.33]). In conclusion, among hemodialysis patients, although there is a U-shaped (paradoxical) association of dialysis-unit-SBP and risk of cardiovascular disease, there is a linear association of out-of-dialysis-unit-SBP with risk of cardiovascular disease. Out-of-dialysis-unit blood pressure provides key information and may be an important therapeutic target.

Blood pressure parameters are associated with all-cause and cause-specific mortality in chronic kidney disease

Previous observational studies reported J or U-shaped associations between blood pressure parameters and mortality in patients with chronic kidney disease (CKD). Here we examined the associations of different blood pressure levels with various causes of death in a CKD population that included patients with eGFR 15-59 ml/min/1.73 m² with underlying hypertension receiving at least one antihypertensive agent. We obtained data on date and cause of death from State Department of Health mortality files and classified deaths into three categories: cardiovascular, malignancy-related, and non-cardiovascular/non-malignancy related. Cox models were fitted for overall mortality, and separate competing risk regression models for each major cause of death category, to evaluate their associations with various systolic and diastolic blood pressures. During a median follow-up of 3.9 years, 13,332 of 45,412 patients died. Systolic blood pressures under 100, 100-109, 110-119, and over 150 (vs. 130-139 mm Hg) were associated with higher all-cause and cardiovascular mortality. Systolic blood pressures under 100 mm Hg and 100-109 were associated with higher non-cardiovascular/non-malignancy related mortality. Diastolic blood pressures under 50 and 50-59 (vs. 70-79 mm Hg) were associated with higher all-cause and non-cardiovascular/non-malignancy-related mortality while diastolic blood pressures over 90 mm Hg was associated with higher cardiovascular but lower non-cardiovascular/non-malignancy related mortality. Thus, in a non-dialysis dependent CKD population, systolic blood pressures under 110 and over 150 mm Hg were associated with cardiovascular and non-cardiovascular/non-malignancy related deaths. However, diastolic blood pressure under 60 mm Hg was associated in contrast with all-cause mortality and non-cardiovascular/non-malignancy-related deaths.

Heart failure in patients with kidney disease

Heart failure (HF) is a leading cause of morbidity and mortality in patients with chronic kidney disease (CKD), and the population of CKD patients with concurrent HF continues to grow. The accurate diagnosis of HF is challenging in patients with CKD in part due to a lack of validated imaging and biomarkers specifically in this population. The pathophysiology between the heart and the kidneys is complex and bidirectional. Patients with CKD have greater prevalence of traditional HF risk factors as well as unique kidney-specific risk factors including malnutrition, acid-base alterations, uraemic toxins, bone mineral changes, anemia and myocardial stunning. These risk factors also contribute to the decline of kidney function seen in patients with subclinical and clinical HF. More targeted HF therapies may improve outcomes in patients with kidney disease as current HF therapies are underutilised in this population. Further work is also needed to develop novel HF therapies for the CKD population.

The effect of magnesium supplementation on vascular calcification in chronic kidney disease-a randomised clinical trial (MAGiCAL-CKD): essential study design and rationale

INTRODUCTION

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular disease and mortality, which is thought to be caused by increased propensity towards vascular calcification (VC). Magnesium (Mg) inhibits phosphate-induced VC in vitro and in animal models and serum Mg is inversely associated with cardiovascular mortality in predialysis CKD and in end-stage renal disease. This paper will describe the design and rationale of a randomised double-blinded placebo-controlled multicentre clinical trial, which will investigate whether oral Mg supplementation can prevent the progression of coronary artery calcification (CAC) in subjects with predialysis CKD.

METHODS AND ANALYSIS

We will randomise 250 subjects with estimated glomerular filtration rate of 15 to 45 mL/min/1.73 m² to 12 months treatment with either slow-release Mg hydroxide 30 mmol/day or matching placebo in a 1:1 ratio. The primary end point is change in CAC score as measured by CT at baseline and after 12 months treatment. Secondary end points include change in pulse wave velocity, bone mineral density, measures of mineral metabolism and clinical end points related to cardiovascular and renal events.

ETHICS AND DISSEMINATION

This trial has been approved by the local biomedical research ethics committees and data protection agencies and will be performed in accordance with the latest revision of the Helsinki Declaration. The trial will examine for the first time the effect of increasing the uptake of a putative VC inhibitor (ie, Mg) on progression of CAC in subjects with predialysis CKD.

TRIAL REGISTRATION NUMBER

NCT02542319, pre-results.