Ambulatory blood pressure and cardiovascular risk in chronic kidney disease

Racial differences in nocturnal dipping status in diabetic kidney disease: Results from the STOP-DKD (Simultaneous Risk Factor Control Using Telehealth to Slow Progression of Diabetic Kidney Disease) study

While racial variation in ambulatory blood pressure (BP) is known, patterns of diurnal dipping in the context of diabetic kidney disease have not been well defined. The authors sought to determine the association of race with nocturnal dipping status among participants with diabetic kidney disease enrolled in the STOP-DKD (Simultaneous Risk Factor Control Using Telehealth to Slow Progression of Diabetic Kidney Disease) trial. The primary outcome was nocturnal dipping-percent decrease in average systolic BP from wake to sleep-with categories defined as reverse dippers (decrease <0%), nondippers (0%-<10%), and dippers (≥10%). Twenty-four-hour ambulatory BP monitoring was completed by 108 participants (54% were nondippers, 24% were dippers, and 22% were reverse dippers). In adjusted models, the common odds of reverse dippers vs nondippers/dippers and reverse dippers/nondippers vs dippers was 2.6 (95% confidence interval, 1.2-5.8) times higher in blacks than in whites. Without ambulatory BP monitoring data, interventions that target BP in black patients may be unable to improve outcomes in this high-risk group.

Glomerular hyperfiltration is a predictor of adverse cardiovascular outcomes

The association between glomerular hyperfiltration and cardiovascular events is not well known. To investigate whether glomerular hyperfiltration is independently associated with risk of adverse outcome we analyzed 8794 participants, average age 52 years enrolled in 8 prospective studies. Of these, 89% had hypertension. Using the 5th and 95th percentiles of the age- and sex-specific quintiles of CKD-EPI-calculated estimated glomerular filtration rate (eGFR), we identified three participant groups with low, high and normal eGFR. The ambulatory pulse pressure interval was wider and nighttime blood pressure fall was smaller in both the low and high than in the normal eGFR participants. During a mean follow-up of 6.2 years, there were 722 cardiovascular events. Crude event rates were significantly higher for both high (1.8 per 100-person-year) and low eGFR groups (2.1 per 100 person-year) as compared with group with normal eGFR (1.2 per 100 person-year). In multivariable Cox models including age, sex, average 24-hour blood pressure, smoking, diabetes, and cholesterol, both high eGFR (hazard ratio 1.5 (95% confidence interval 1.2-2.1) and low eGFR (2.0 [1.5-2.6]) participants had a significantly higher risk of cardiovascular events as compared to those with normal eGFR. Addition of body mass index to the multivariable survival model did not change the magnitude of hazard estimates. Thus, glomerular hyperfiltration is a strong and independent predictor of cardiovascular events in a large multiethnic population of predominantly hypertensive individuals. Our findings support a U-shaped relationship between eGFR and adverse outcome.

Hypertension in pediatric patients with chronic kidney disease: management challenges

In contrast to adults where hypertension is a leading cause of chronic kidney disease, in pediatrics, hypertension is predominantly a sequela, however, an important one that, like in adults, is likely associated with a more rapid decline in kidney function or progression of chronic kidney disease to end stage. There is a significant issue with unrecognized, or masked, hypertension in childhood chronic kidney disease. Recent evidence and, therefore, guidelines now suggest targeting a blood pressure of <50th percentile for age, sex, and height in children with proteinuria and chronic kidney disease. This often cannot be achieved by monotherapy and additional agents need to be added. Blockade of the renin angiotensin aldosterone system represents the mainstay of therapy, although often limited by the side effect of hyperkalemia. The addition of a diuretic, at least in the earlier stages of chronic kidney disease, might help mitigate this problem.

Influence of HbA1c on short-term blood pressure variability in type 2 diabetic patients with diabetic nephropathy

The aim of this study was to understand the characteristics of blood pressure (BP) variability in subjects with diabetic nephropathy (DN), and identify the probable predictors affecting BP variability. Fifty-one chronic kidney disease (CKD)-hypertensive patients without diabetes (NDN group) and sixty type 2 diabetic patients with overt DN (DN group) were enrolled in this study. The values of short-term BP variability were obtained from 24 h ambulatory BP monitoring (ABPM). Variance analysis or nonparametric analysis revealed that 24-h systolic BP variability and nighttime systolic BP variability of the DN group were significantly higher than those of the NDN group [(12.23±3.66) vs. (10.74±3.83) mmHg, P<0.05; (11.23±4.82) vs. (9.48±3.69) mmHg, P<0.05]. Then the patients of the DN group were divided into two groups according to glycated hemoglobin (HbA1c) level: Group A (HbA1c<7%) and Group B (HbA1c≥7%), and the t-test showed that patients in Group B had larger 24-h diastolic, daytime diastolic, and nighttime systolic/diastolic BP variability compared with Group A. In the DN group, partial correlation analysis revealed that HbA1c exhibited a strong association with 24-h diastolic, daytime diastolic, nighttime systolic and diastolic BP variability (P<0.001, P<0.001, P<0.05, and P<0.001, respectively). Taken together, larger short-term BP variability was detected in hypertensive type 2 diabetic patients with overt nephropathy and renal insufficiency. It may imply that the optimal BP variability level could benefit from a better glycaemic control.

Profile of interdialytic ambulatory blood pressure in a cohort of Chinese patients

Management of hypertension is one of the fundamental interventions in dialysis patients. However, the profile of interdialytic blood pressure (BP) in Chinese dialysis patients remains elusive. We aim to investigate this issue as well as the effect of antihypertensive medication in this population. We performed 44-h ambulatory BP in 90 patients on maintenance hemodialysis. Patients were classified as 'dipping', 'non-dipping' or 'reverse-dipping' based on night/day ratio (N/D) of systolic BP on nondialysis day. The prevalence of blunted circadian BP pattern was strikingly high (92.2%), with more than half of the patients (55.6%) classified as reverse-dipping. There was a close association between high erythropoietin (EPO) dose used and deteriorated circadian rhythm. Patients in the dipping group also displayed a dipping state for heart rate (HR) compared with the other two groups (N/D of HR: 81.5 ± 6.6 vs 92.1 ± 6.0 and 91.3 ± 10.7, P=0.02). Only 26.7% patients had a controlled nocturnal BP. Patients with bedtime dosing had lower N/D of systolic BP compared with patients without (100.1 ± 7.0 vs 105.2 ± 7.1, P=0.01). Non-dipping and reverse-dipping are highly prevalent in Chinese patients. EPO use and autonomic dysfunction may contribute to the blunted circadian rhythm. More tightly control of nighttime BP is an urgent need and bedtime dosing may be beneficial.

How should we manage a patient with masked hypertension?

A number of studies have shown that masked hypertension (MH) confers an increased risk of target organ damage and of cardiovascular events suggesting that patients with MH would benefit from antihypertensive treatment. However, there is no general agreement about how this condition should be diagnosed. Although ambulatory blood pressure monitoring (ABPM) and self blood pressure measurement (SBPM) provide different and complementary clinical information, the recently published ESH/ESC guidelines for the management of arterial hypertension suggest that for initial assessment of the patient, SBPM may be more suitable in primary care and ABPM in specialist care. If SBPM provides borderline values it is advisable to confirm the diagnosis of MH with ABPM. As the prevalence of MH declines with repeated ABPMs the diagnosis of MH should be based on at least two ABPMs. Patients with MH should undergo a careful diagnostic work-up to assess the existence of additional risk factors including a worsened metabolic profile and the presence of target organ involvement. Treatment of the patient with MH should initially be addressed to improve the patient's lifestyle in order to decrease out-of-office blood pressure and to ameliorate metabolic data. If non-pharmacological measures are insufficient to normalize blood pressure, MH may benefit from pharmacological treatment but no clinical trial has been implemented as yet with the specific purpose of testing this hypothesis. Despite this lack of evidence, the 2013 ESH/ESC guidelines have recommended that in patients with MH also drug treatment should be considered because in patients with MH the risk of adverse outcome is very close to that in sustained hypertension. When ambulatory blood pressure is measured, pharmacological treatment may be modulated according to whether blood pressure is elevated during daytime hours or during sleep.

Prognostic value of 48-hour ambulatory blood pressure measurement and cardiovascular mortality in hemodialysis patients

BACKGROUND

Hypertension is common and contributes to high cardiovascular morbidity and mortality in hemodialysis (HD) patients. It is unknown which blood pressure (BP) better defines the influence on cardiovascular mortality. The purpose of our study was to analyze the relationship between various BP measurements, traditional risk factors, markers of asymptomatic atherosclerosis [left ventricular mass (LVM), carotid intima media thickness (IMT)], and cardiovascular mortality in HD patients.

METHODS

Seventy-three patients (44 males and 29 females; mean age: 54.2 years) were included. BP was measured before and after HD and 48-hour ambulatory blood pressure monitoring (ABPM) was performed. Using sonography, the LVM index and carotid IMT were measured.

RESULTS

During a follow-up period up to 3,664 days, 28 patients died - 16 of them from cardiovascular causes. In a Cox regression model, which included age, gender, smoking, diabetes, sensitive C-reactive protein, albumin, hemoglobin, troponin T, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, calcium, phosphorus, carotid IMT, and LVM index, only 48-hour systolic ABPM (p = 0.037) and 48-hour diastolic ABPM (p = 0.006) turned out to be independent predictors of cardiovascular death.

CONCLUSION

Only 48-hour ABPM and not single BP measurements before or after HD were associated with cardiovascular mortality in HD patients.