Ambulatory blood pressure variability and risk of cardiovascular events, all-cause mortality, and progression of kidney disease

Prognostic utility of rhythmic components in 24-h ambulatory blood pressure monitoring for the risk stratification of chronic kidney disease patients with cardiovascular co-morbidity

Chronic kidney disease (CKD) represents a significant global burden. Hypertension is a modifiable risk factor for rapid progression of CKD. We extend the risk stratification by introducing the non-parametric determination of rhythmic components in 24-h profiles of ambulatory blood pressure monitoring (ABPM) in the Chronic Renal Insufficiency Cohort (CRIC) and the African American Study for Kidney Disease and Hypertension (AASK) cohort using Cox proportional hazards models. We find that rhythmic profiling of BP through JTK_CYCLE analysis identifies subgroups of CRIC participants that were more likely to die due to cardiovascular causes. While our fully adjusted model shows a trend towards a significant association between absent cyclic components and cardiovascular death in the full CRIC cohort (HR: 1.71,95% CI: 0.99-2.97, p = 0.056), CRIC participants with a history of cardiovascular disease (CVD) and absent cyclic components in their BP profile had at any time a 3.4-times higher risk of cardiovascular death than CVD patients with cyclic components present in their BP profile (HR: 3.37, 95% CI: 1.45-7.87, p = 0.005). This increased risk was not explained by the dipping or non-dipping pattern in ABPM. Due to the large differences in patient characteristics, the results do not replicate in the AASK cohort. This study suggests rhythmic blood pressure components as a potential novel biomarker to unmask excess risk among CKD patients with prior cardiovascular disease.

Visit-to-visit blood pressure variability and the risk of cardiovascular disease: a prospective cohort analysis

Large blood pressure (BP) variability contributed to subclinical brain disease thus may be implicated in the development of cardiovascular disease (CVD). This study included 64,810 CVD-free participants who attended the first two examinations from the Kailuan study to investigate the association of BP variation, considering its magnitude, direction, and time interval prior to CVD diagnosis, with the risk of CVD in Chinese population. Magnitude and directional BP variability was calculated as absolute BP difference or BP difference value divided by mean BP over 2 sequential visits, respectively. During a median follow-up of 10.91 years, a total of 4129 cases of CVD. A large SBP variability (the highest vs the lowest tertile) was associated with a higher risk of CVD (adjusted HR, 1.31; 95% CI, 1.22-1.41). The associations were stronger with longer time intervals, the hazard ratio (HR) with 95% confidence interval (CI) for CVD was 1.30 (95% CI, 1.20-1.39) at 1 years, 1.32 (1.18-1.40) at 3 years, and 1.34 (1.20-1.45) at 5 years. For directional SBP variability, rise in SBP was associated with an increased risk of CVD (HR, 6.17; 95% CI, 5.65-6.75), while fall in SBP was associated with a decreased risk of CVD (HR, 0.52; 95% CI, 0.46-0.59). Subgroup analysis showed the significant associations were only observed in men (Pint = 0.0010). Similar patterns were observed for DBP variability and CVD subtypes. The results indicated that a large SBP variation in rise direction was associated with an increased risk of incident CVD, especially in men.

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.

Prognostic utility of rhythmic components in 24-hour ambulatory blood pressure monitoring for the risk stratification of chronic kidney disease patients with cardiovascular co-morbidity

Background

Chronic kidney disease (CKD) represents a significant global burden. Hypertension is a modifiable risk factor for rapid progression of CKD.

Methods

We extend the risk stratification by introducing the non-parametric determination of rhythmic components in 24-hour profiles of ambulatory blood pressure monitoring (ABPM) in the African American Study for Kidney Disease and Hypertension (AASK) cohort and the Chronic Renal Insufficiency Cohort (CRIC) using Cox proportional hazards models.

Results

We find that rhythmic profiling of BP through JTK_Cycle analysis identifies subgroups of CRIC participants at advanced risk of cardiovascular death. CRIC participants with a history of cardiovascular disease (CVD) and absent cyclic components in their BP profile had at any time a 3.4-times higher risk of cardiovascular death than CVD patients with cyclic components present in their BP profile (HR: 3.38, 95% CI: 1.45-7.88, p=0.005). This substantially increased risk was independent of whether ABPM followed a dipping or non-dipping pattern whereby non-dipping or reverse dipping were not significantly associated with cardiovascular death in patients with prior CVD (p>0.1). In the AASK cohort, unadjusted models demonstrate a higher risk in reaching end stage renal disease among participants without rhythmic ABPM components (HR:1.80, 95% CI: 1.10-2.96); however, full adjustment abolished this association.

Conclusions

This study proposes rhythmic blood pressure components as a novel biomarker to unmask excess risk among CKD patients with prior cardiovascular disease.

Blood Pressure Variability and the Progression of Chronic Kidney Disease: a Systematic Review and Meta-Analysis

BACKGROUND

Blood pressure variability (BPV) is a risk factor for poor prognosis including cardiovascular events, chronic kidney disease, and mortality, independent of elevated BP.

METHODS

We searched PubMed/Medline, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to November 23, 2022. Cohort studies reporting the association between BPV and chronic kidney disease (CKD) progression were selected. Hazard ratios were pooled using a random-effects model. Meta-regression, subgroup analyses, and sensitivity analyses were conducted.

RESULTS

A total of 23 studies were included in this systematic review and meta-analysis. Increased BPV was associated with progression of CKD (HR: 1.21, 95% CI: 1.09-1.33) and incidence of ESRD (HR: 1.08, 95% CI: 1.08-1.30). Among the different BPV metrics, high variation independent of mean (VIM), coefficient of variation (CV), standard deviation (SD), and average real variability (ARV) were indicated as predictors of CKD progression.

DISCUSSION

Increased BPV was associated with CKD progression.

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.

Prevalence and clinical characteristics of primary aldosteronism in a tertiary-care center in Korea

Approximately 29% of Korean adults have hypertension; however, the prevalence of primary aldosteronism among the hypertensive population is largely unknown. The aim of our study was to evaluate the prevalence and clinical characteristics of primary aldosteronism in a tertiary-care center in Korea. We retrospectively analyzed 1173 patients with newly diagnosed or preexisting hypertension who were referred to our tertiary-care hospital between January 2013 and December 2018. Patients were screened for primary aldosteronism with the aldosterone-renin ratio and underwent a saline infusion test for diagnostic confirmation. Adrenal computed tomography and adrenal venous sampling were performed for subtype classification for primary aldosteronism. Among the 1173 patients (mean age, 51.8 years; women, 53.2%), 360 (30.7%) had positive screening-test results, of whom 71 (6.1%) were finally diagnosed with primary aldosteronism. Conclusive subtype differentiation was made in 55 patients, of whom 15 (27%) had an aldosterone-producing adenoma, 4 (7%) had unilateral adrenal hyperplasia, and 36 (66%) had bilateral adrenal hyperplasia. Patients with primary aldosteronism had a higher ambulatory blood pressure, left ventricular mass index, and urinary albumin-to-creatinine ratio than those without. Moreover, the primary aldosteronism group had a higher prevalence of left ventricular hypertrophy and albuminuria than the non-primary aldosteronism group. Primary aldosteronism may be more common (6.1%) among Korean patients with hypertension than generally recognized. Primary aldosteronism was associated with a higher degree and prevalence of target organ damage and a higher blood pressure level. Wide application of screening tests for primary aldosteronism may be beneficial in detecting this potentially curable cause of hypertension.

Effect of patient gender on short-term blood pressure variability in hemodialysis patients

Increased blood pressure variability (BPV) is strongly associated with cardiovascular events in end-stage kidney disease patients. Male hemodialysis patients present higher cardiovascular risk compared with females. The aim of this study is to investigate sex differences in short-term BPV in hemodialysis patients. 129 male and 91 female hemodialysis patients that underwent 48-h ABPM were included in this analysis. Standard deviation (SD), weighted SD (wSD), coefficient of variation (CV), and average real variability (ARV) of SBP and DBP were calculated with validated formulas. Age, dialysis vintage and history of major comorbidities did not differ between men and women. 48-h SBP/DBP (137.2 ± 17.4/81.9 ± 12.1 mmHg vs 132.2 ± 19.2/75.9 ± 11.7 mmHg, p = 0.045/<0.001) was significantly higher in men than women. During the 48-h period, all systolic BPV indices were similar between men and women (48-h SBP-ARV: 12.0 ± 2.9 vs 12.1 ± 3.2 mmHg, p = 0.683); 48-h DBP-SD, DBP-wSD and DBP-ARV (9.1 ± 1.6 vs 8.4 ± 1.8 mmHg, p = 0.005) were higher in men. In conclusion, short-term diastolic BPV indices are higher in male than female hemodialysis patients. Increased BPV may impact on the higher incidence of cardiovascular events observed in male hemodialysis patients.

Visit-to-visit blood pressure variability and the risk of stroke in the Netherlands: A population-based cohort study

BACKGROUND

Apart from blood pressure level itself, variation in blood pressure has been implicated in the development of stroke in subgroups at high cardiovascular risk. We determined the association between visit-to-visit blood pressure variability and stroke risk in the general population, taking into account the size and direction of variation and several time intervals prior to stroke diagnosis.

METHODS AND FINDINGS

From 1990 to 2016, we included 9,958 stroke-free participants of the population-based Rotterdam Study in the Netherlands. This is a prospective cohort study including participants aged 45 years and older. Systolic blood pressure (SBP) variability was calculated as absolute SBP difference divided by mean SBP over 2 sequential visits (median 4.6 years apart). Directional SBP variability was defined as SBP difference over 2 visits divided by mean SBP. Using time-varying Cox proportional hazards models adjusted for age, sex, mean SBP, and cardiovascular risk factors, hazard ratios (HRs) for stroke up to January 2016 were estimated per SD increase and in tertiles of variability. We also conducted analyses with 3-, 6-, and 9-year intervals between variability measurement and stroke assessment. These analyses were repeated for diastolic blood pressure (DBP). The mean age of the study population was 67.4 ± 8.2 years and 5,776 (58.0%) were women. During a median follow-up of 10.1 years, 971 (9.8%) participants had a stroke, including 641 ischemic, 89 hemorrhagic, and 241 unspecified strokes. SBP variability was associated with an increased risk of hemorrhagic stroke (HR per SD 1.27, 95% CI 1.05-1.54, p = 0.02) and unspecified stroke (HR per SD 1.21, 95% CI 1.09-1.34, p < 0.001). The associations were stronger for all stroke subtypes with longer time intervals; the HR for any stroke was 1.29 (95% CI 1.21-1.36, p < 0.001) at 3 years, 1.47 (95% CI 1.35-1.59, p < 0.001) at 6 years, and 1.38 (95%CI 1.24-1.51, p < 0.001) at 9 years. For DBP variability, we found an association with unspecified stroke risk. Both the rise and fall of SBP and the fall of DBP were associated with an increased risk for unspecified stroke. Limitations of the study include that, due to an average interval of 4 years between visits, our findings may not be generalizable to blood pressure variability over shorter periods.

CONCLUSIONS

In this population-based study, we found that visit-to-visit blood pressure variation was associated with an increased risk of unspecified and hemorrhagic stroke, independent of direction of variation or mean blood pressure.

Prevalence and prognosis of refractory hypertension diagnosed using ambulatory blood pressure measurements

The prognosis of refractory hypertension is largely unknown due to its low prevalence. This study aimed to investigate the prognosis of refractory hypertension and compare it with those of resistant and nonresistant hypertension. We retrospectively analyzed the data of 16,284 participants with hypertension who underwent ambulatory blood pressure (BP) monitoring between 2012 and 2019 at a tertiary center. Uncontrolled BP was defined as a 24-h BP ≥ 130/80 mmHg as assessed by ambulatory BP monitoring. Resistant hypertension was defined as uncontrolled BP despite the use of three antihypertensive medications, including a diuretic or the use of ≥4 drugs regardless of BP control. Refractory hypertension was defined as uncontrolled BP despite the use of ≥5 antihypertensive medications. Among 16,284 patients with hypertension (mean age 59.2 ± 15.5 years, 52.7% men), 1501 (9.2%) and 150 (0.9%) patients had resistant and refractory hypertension, respectively. The prevalence of chronic kidney disease, end-stage renal disease, heart failure, previous stroke, left ventricular hypertrophy, and the riser/nondipper patterns of circadian BP rhythm progressively increased from patients with nonresistant hypertension to patients with resistant hypertension to patients with refractory hypertension. During a median follow-up of 3.9 years, the risk of cardiovascular mortality progressively increased from patients with nonresistant hypertension to patients with resistant hypertension (hazard ratio 1.62, 95% confidence interval 1.16-2.26) to patients with refractory hypertension (hazard ratio 5.22, 95% confidence interval 3.04-8.96). In conclusion, refractory hypertension, defined as uncontrolled ambulatory BP levels, was associated with a higher risk of all-cause and cardiovascular mortality than nonresistant or resistant hypertension.

Ambulatory blood pressure and drug treatment for orthostatic hypotension as predictors of mortality in patients with Multiple System Atrophy

OBJECTIVES

Multiple system atrophy (MSA) is a rare fatal neurodegenerative disease characterized by parkinsonism, cerebellar ataxia and autonomic failure. This study aimed at investigating possible associations between mortality, 24H blood pressure (BP) level and variability, and drug treatments for orthostatic hypotension (OH) in MSA patients.

METHODS

One hundred and twenty-nine patients followed at the French Reference Center for MSA who underwent routine 24H ambulatory BP monitoring, were included. Unified MSA Rating Scale (UMSARS) scores, drug treatments and the occurrence and cause of death were recorded.

RESULTS

Seventy patients died during follow-up (2.9±1.8 years), mainly from terminal illness, pulmonary or sudden death. Multivariate Cox regression analysis, after adjustment for gender, disease duration and severity (UMSARS I+II score), showed that increased daytime systolic BP variability, OH severity and OH drug treatment were independently correlated with mortality. OH treatment was associated with the risk of cardiac causes and/or sudden death (p=0.01). In a fully adjusted model, male gender [(female vs male) Hazard ratio (HR): 0.56 95% CI [0.34-0.94] p=0.03], UMSARS I+II score [HR: 1.04 95% CI [1.02-1.06] p<0.01], systolic BP daytime variability [HR: 3.66 95% CI (1.46-9.17 p<0.01] and OH treatment [HR: 2.13 95 % CI [1.15- 3.94]; p=0.02] predicted mortality.

CONCLUSION

Increased daytime BP variability and OH treatment were predictive of mortality in patients with MSA, independently from disease severity. Further studies are required to assess if these associations are explained by more severe autonomic dysfunction or if OH treatment exposes "per se" to a specific risk in this population.

Association of Urinary Potassium Excretion with Blood Pressure Variability and Cardiovascular Outcomes in Patients with Pre-Dialysis Chronic Kidney Disease

Dietary potassium intake is a dilemma in patients with chronic kidney disease (CKD). We investigated the association of urine potassium excretion, a surrogate for dietary potassium intake, with blood pressure variability (BPV) and cardiovascular (CV) outcomes in patients with pre-dialysis CKD. A total of 1860 participants from a cohort of pre-dialysis CKD (KNOW-CKD) patients were divided into the quartiles by spot urine potassium-to-creatinine ratio. The first quartile (26.423 ± 5.731 mmol/gCr) was defined as low urine potassium excretion. Multivariate linear regression analyses revealed an independent association of low urine potassium excretion with high BPV (adjusted β coefficient 1.163, 95% confidence interval 0.424 to 1.901). Cox regression analyses demonstrated that, compared to high urine potassium excretion, low urine potassium excretion is associated with increased risk of CV events (adjusted hazard ratio 2.502, 95% confidence interval 1.162 to 5.387) but not with all-cause mortality. In conclusion, low urine potassium excretion is associated with high BPV and increased risk of CV events in patients with pre-dialysis CKD. The restriction of dietary potassium intake should be individualized in patients with pre-dialysis CKD.

Correlations Among Visit-to-Visit Blood Pressure Variability and Treatment With Antihypertensive Medication With Long-Term Adverse Outcomes in a Large Veteran Cohort

BACKGROUND

Blood pressure variability (BPV) is associated with adverse events (AEs) independently of hypertension. It has been suggested that calcium channel blockers (CCBs) may reduce BPV, and thus be particularly valuable in hypertensives with high BPV. We sought to investigate how CCB affect BPV progression and whether long-term adverse effects of BPV differ after CCB treatment than after treatment with other antihypertensives.

METHODS

We retrospectively analyzed 25,268 US veterans who had been followed for 3 years without hypertensive therapy, started on a single class of antihypertensive agents (thiazides, CCBs, ACE inhibitors, or beta blockers [BBs]), treated for 6 years, and then followed for 3 additional years. BPV was calculated as SD of systolic or diastolic blood pressures from at least 10 measurements over each 3-year period. A combined AE endpoint included hospitalization, coronary artery bypass grafting, carotid endarterectomy, angioplasty, amputation, arteriovenous fistula creation, and mortality was assessed in years 9-12.

RESULTS

Post-medication high BPV and BB or thiazide use were associated with increased AE risk. Medication type also affected mean post-medication BPV. The effects of medications except for BBs on AE and mortality was independent of the patient BPV.

CONCLUSIONS

The possible deleterious effects of thiazides should be considered within the context of the study population, who were mostly male and received only a single class of hypertensives. While CCB may ameliorate BPV over time, this study does not support choosing CCB over other agents specifically to lessen BPV-associated risk.

Association of Blood Pressure Variability and Diuretics With Cardiovascular Events in Patients With Chronic Kidney Disease Stages 1-5

Visit-to-visit blood pressure variability (BPV) is associated with cardiovascular events in the general population. Data are scarce in chronic kidney disease. We hypothesized that BPV would be associated with cardiovascular outcomes, death, and end-stage kidney disease (ESKD) and that diuretics would modify these associations in patients with chronic kidney disease. We studied US Veterans with nondialysis chronic kidney disease stages 1-5 and hypertension on nondiuretic antihypertensive monotherapy. At the time of second antihypertensive agent prescription, we propensity-matched for exposure to a loop or thiazide diuretic versus any other antihypertensive. BPV was defined as the coefficient of variation of systolic blood pressure over 6 months after second agent prescription. Cox proportional hazards regression measured associations of BPV with a primary cardiovascular event composite (fatal or nonfatal myocardial infarction or ischemic stroke; heart failure hospitalization). Secondary outcomes included all-cause death, each primary outcome component, end-stage kidney disease, and cardiovascular death. There were 31 394 participants in each group. BPV was associated with composite cardiovascular events, hazard ratio (95% CI) at second, third, fourth, and fifth versus first quintile: 1.79 (1.53-2.11), 2.32 (1.99-2.71), 2.60 (2.24-3.02), and 3.12 (2.68-3.62). Diuretics attenuated associations between the fourth and fifth BPV quintiles with composite events (P_interaction=0.03 and 0.04, respectively). BPV was associated with all secondary outcomes except end-stage kidney disease, with no diuretic interactions. BPV was associated with cardiovascular events and death but not end-stage kidney disease in patients with chronic kidney disease, with attenuated associations with cardiovascular events in the diuretic-treated group at high BPV quintiles. Future studies should investigate whether other antihypertensive classes modify these risks.