Validation of spot urine in estimating 24-h urinary sodium, potassium and sodium-to-potassium ratio during three different sodium diets in healthy adults.

PURPOSE: To evaluate the validity of spot urine assay methods in estimating the 24-h urinary sodium, potassium and sodium-to-potassium ratio during three different sodium diets. MATERIALS AND METHODS: Twelve healthy volunteers were asked to adhere to 3 dietary sodium targets (3.3-5.0g/day,<3.3 g/day and >5.0 g/day) for three consecutive weeks and to measure salt excretion daily in spot urine samples using a self-monitoring device. On day 7 of each week, 24-h urine was collected to compare measured with estimated 24-h salt excretion (by the Kawasaki, Tanaka and INTERSALT equations). RESULTS: Correlation coefficients relating measured and estimated 24-h sodium excretion were low and not significant for Kawasaki and INTERSALT and moderate for the Tanaka equation (τ 0.56-0.64,p<.05). Bland-Altman plots showed considerable differences between estimated and measured sodium excretion across all salt diets. Over 40% of the participants showed an absolute difference between measured and estimated 24-h sodium of more than 1000 mg/day. The correlation coefficients between 24-h and spot Na/K ratio were 0.67, 0.94 and 0.85(p<.05), and mean differences were 0.59, 0.06 and 0.48 for the intermediate, low and high sodium diets, respectively. CONCLUSION: These findings do not support estimation of individual 24-h salt excretion from spot urine by the Kawasaki, Tanaka, or INTERSALT formula. Plain language summaryAccurate monitoring of salt intake is essential to improve BP control. At present, measurement of sodium and potassium excretion in multiple non-consecutive 24-h urinary collections is considered the gold standard for measuring dietary sodium intake. However, this method is burdensome, time-consuming and error prone.Therefore, we assessed and compared the validity of three formula-based approaches to estimate 24-h urinary sodium and potassium excretion and the Na/K ratio from spot urine samples measured by a self-monitoring device under three different sodium diets using 24-h urine collections as the reference.We conclude that use of three commonly used equations that estimate 24-h urinary sodium and potassium excretion result in substantial bias, poor precision and poor accuracy and are therefore not recommended. The Na/K ratio based on multiple casual urine samples may be a useful, low-burden, low-cost alternative method to 24-h urine collection for monitoring daily salt intake.

Number of measurement days needed for obtaining a reliable estimate of home blood pressure and hypertension status.

PURPOSE: Out-of-office blood pressure (BP) measurements are essential for the diagnosis and monitoring of hypertension. Current guidelines vary in their recommendations on the protocol for home blood pressure monitoring (HBPM). We aimed to assess the number of blood pressure (BP) measurement days needed for a reliable estimation of true home BP (the expected BP level over time) and hypertension status, using the European guideline-based 7-day HBPM protocol as a reference. MATERIALS AND METHODS: Data from 567 adults who performed a 7-day HBPM were analysed. Blood pressure was measured twice daily (morning and evening readings) using the Microlife Average Mode (MAM), which takes a weighted average of 3 consecutive BP readings. The variability of average BP for an increasing number of measurements was assessed using a linear mixed model including a random intercept per individual and correlated residuals. The reliability of home hypertension status was assessed by the κ statistic. RESULTS: Mean home BP of the population was 143 ± 16/84 ± 10 mm Hg. On average, the first BP measurements gave the highest values which then decreased over time. Systolic BP in the morning was systematically lower than systolic BP in the evening (142 ± 17mm Hg versus 144 ± 17 mm Hg, p <0.05). The average of 7 twice-daily MAM BP measurements was at most 5.2/3.3 mm Hg higher and 9.5/4.8 mm Hg lower than the true home BP for 95% of the individuals. Reducing this protocol to 3 days increased this variability by 1.5/1.0 mm Hg and 4.8/2.3 mm Hg, respectively. For diagnosing home hypertension, there was good agreement with a minimum of 4.5 days of HBPM (ĸ-statistic 0.88; 95% Confidence Interval: 0.82-0.94). CONCLUSION: Twice-daily MAM BP measurements for 3 consecutive days provide a reliable estimate of home BP. At least 4.5 consecutive days of HBPM are required for a reliable diagnosis of home hypertension.

Clinical characteristics do not reliably identify non-adherence in patients with uncontrolled hypertension.

PURPOSE: Chemical adherence testing is a reliable method to assess adherence to antihypertensive drugs. However, it is expensive and has limited availability in clinical practice. To reduce the number and costs of chemical adherence tests, we aimed to develop and validate a clinical screening tool to identify patients with a low probability of non-adherence in patients with uncontrolled hypertension. MATERIALS AND METHODS: In 495 patients with uncontrolled hypertension referred to the University Medical Centre Utrecht (UMCU), the Netherlands, a penalised logistic regression model including seven pre-specified easy-to-measure clinical variables was derived to estimate the probability of non-adherence. Non-adherence was defined as not detecting at least one of the prescribed antihypertensive drugs in plasma or urine. Model performance and test characteristics were evaluated in 240 patients with uncontrolled hypertension referred to the Heartlands Hospital, United Kingdom. RESULTS: Prevalence of non-adherence to antihypertensive drugs was 19% in the UMCU and 44% in the Heartlands Hospital population. After recalibration of the model's intercept, predicted probabilities agreed well with observed frequencies. The c-statistic of the model was 0.63 (95%CI 0.53-0.72). Predicted probability cut-off values of 15%-22.5% prevented testing in 5%-15% of the patients, carrying sensitivities between 97% (64-100) and 90% (80-95), and negative predictive values between 74% (10-99) and 70% (50-85). CONCLUSION: The combination of seven clinical variables is not sufficient to reliably discriminate adherent from non-adherent individuals to safely reduce the number of chemical adherence tests. This emphasises the complex nature of non-adherence behaviour and thus the need for objective chemical adherence tests in patients with uncontrolled hypertension.

Baroreflex Amplification and Carotid Body Modulation for the Treatment of Resistant Hypertension.

PURPOSE OF REVIEW: Patients with true resistant hypertension (RH) are characterized by having high sympathetic activity and therefore potentially benefit from treatments such as baroreflex amplification (baroreflex activation therapy (BAT) or endovascular baroreflex amplification therapy (EVBA)) or carotid body (CB) modulation. This review aims at providing an up-to-date overview of the available evidence regarding these two therapies. RECENT FINDINGS: In recent years, increasing evidence has confirmed the potential of baroreflex amplification, either electrically (Barostim neo) or mechanically (MobiusHD), to improve blood pressure control on short- and long-term with only few side effects, in patients with RH. Two studies regarding unilateral CB resection did not show a significant change in blood pressure. Only limited studies regarding CB modulation showed promising results for transvenous CB ablation, but not for unilateral CB resection. Despite promising results from mostly uncontrolled studies, more evidence regarding the safety and efficacy from ongoing large randomized sham-controlled trials is needed before baroreflex amplification and CB modulation can be implemented in routine clinical practice.

Smartphone Application-Assisted Home Blood Pressure Monitoring Compared With Office and Ambulatory Blood Pressure Monitoring in Patients With Hypertension: the AMUSE-BP Study.

BACKGROUND: The development of automated, smartphone application (app)-assisted home blood pressure monitoring (HBPM) allows for standardized measurement of blood pressure (BP) at home. The aim of this study was to evaluate the (diagnostic) agreement between app-assisted HBPM, automated office BP (OBP), and the reference standard 24-hour ambulatory BP monitoring (ABPM). METHODS: In this open randomized 5-way cross-over study, patients diagnosed with hypertension were randomized to one of 10 clusters, each containing 5 BP measurement methods (ABPM, HBPM, attended OBP, unattended OBP, and unattended 30-minute BP) in different order. RESULTS: In total, 113 patients were included. The average 24-hour ABPM was 126±11/73±8 mm Hg compared with 141±14/82±10 mm Hg with app-assisted HBPM, 134±13/80±9 mm Hg with unattended 30-minute BP, 137±16/81±11 mm Hg with attended OBP, and 135±15/81±10 mm Hg with unattended OBP monitoring. Diagnostic agreement between app-assisted HBPM and 24-hour ABPM for diagnosing sustained (OBP >140/90 mm Hg and ABPM ≥130/80 mm Hg or HBPM ≥135/85 mm Hg), white-coat (OBP ≥140/90 mm Hg and ABPM <130/80 mm Hg or HBPM <135/85 mm Hg), and masked hypertension (OBP <140/90 mm Hg and ABPM ≥130/80 mm Hg or HBPM ≥135/85 mm Hg) was fair-to-moderate (κ statistics ranging from 0.34 to 0.40). App-assisted HBPM had high sensitivities (78%-91%) and negative predictive values (90%-97%) for diagnosing sustained and masked hypertension. CONCLUSIONS: This study showed a considerable (diagnostic) disagreement between app-assisted HBPM and ABPM. App-assisted HBPM had high sensitivity in the diagnosis of sustained and masked hypertension and may therefore be used as complementary to, but not a replacement of, ABPM.

The effect of endovascular baroreflex amplification on central sympathetic nerve circuits and cerebral blood flow in patients with resistant hypertension: A functional MRI study.

Background: Endovascular baroreflex amplification (EVBA) by implantation of the MobiusHD is hypothesized to lower blood pressure by decreasing sympathetic activity through the mechanism of the baroreflex. In the present exploratory study we investigated the impact of MobiusHD implantation on central sympathetic nerve circuits and cerebral blood flow (CBF) in patients with resistant hypertension. Materials and methods: In thirteen patients, we performed blood oxygenation level-dependent functional magnetic resonance imaging (BOLD fMRI) at rest and during Valsalva maneuvers, before and 3 months after EVBA. Data were analyzed using a whole-brain approach and a brainstem-specific analysis. CBF was assessed using arterial spin labeling MRI. Results: Resting-state fMRI analysis did not reveal significant differences in functional connectivity at 3 months after EVBA. For the Valsalva maneuver data, the whole-brain fMRI analysis revealed significantly increased activation in the posterior and anterior cingulate, the insular cortex, the precuneus, the left thalamus and the anterior cerebellum. The brainstem-specific fMRI analysis showed a significant increase in BOLD activity in the right midbrain 3 months after EVBA. Mean gray matter CBF (partial volume corrected) decreased significantly from 48.9 (9.9) ml/100 gr/min at baseline to 43.4 (13.0) ml/100 gr/min (p = 0.02) at 3 months. Conclusions: This first fMRI pilot study in patients with resistant hypertension treated with EVBA showed a significant increase in BOLD activity during the Valsalva maneuver in brain regions related to sympathetic activity. No notable signal intensity changes were observed in brain areas involved in the baroreflex circuit. Future randomized controlled studies are needed to investigate whether the observed changes are directly caused by EVBA. Clinical trial registration: www.clinicaltrials.gov, identifier: NCT02827032.

Genetic variants associated with low-density lipoprotein cholesterol and systolic blood pressure and the risk of recurrent cardiovascular disease in patients with established vascular disease.

BACKGROUND AND AIMS: Polygenic risk scores (PRSs) can be used to quantify the effect of genetic contribution to LDL-cholesterol (LDL-C) and systolic blood pressure (SBP). Several PRSs for LDL-C and SBP have been shown to be associated with cardiovascular disease (CVD) in the general population. This study aimed to evaluate the effect of an LDL-C PRS and an SBP PRS on the risk of recurrent CVD in patients with CVD. METHODS: Genotyping was performed in 4,416 patients included in the UCC-SMART study. Weighted LDL-C PRS (279 LDL-C-related SNPs) and SBP PRS (425 SBP-related SNPs) were calculated. Linear regression models were used to evaluate the relation between both PRSs and LDL-C and SBP. The effects of the LDL-C PRS and SBP PRS, and its combination on the risk of recurrent CVD (stroke, myocardial infarction, and vascular death) were analyzed with Cox proportional-hazard models. RESULTS: Per SD increase in LDL-C PRS, LDL-C increased by 0.18 mmol/L (95%CI 0.15-0.21). Per SD increase in SBP PRS, SBP increased by 3.19 mmHg (95%CI 2.60-3.78). During a follow-up of 11.7 years (IQR 9.2-15.0) 1,198 recurrent events occurred. Neither the LDL-C nor the SBP PRS were associated with recurrent CVD (HR 1.05 per SD increase in LDL-C PRS (95%CI 0.99-1.11) and HR 1.04 per SD increase in SBP PRS (95%CI 0.98-1.10)). The combination of both scores was neither associated with recurrent CVD (HR 1.09; 95%CI 0.93-1.28). CONCLUSIONS: In patients with vascular disease, LDL-C PRS and SBP PRS, both separately and in combination, were not significantly associated with recurrent CVD.

The relation between urinary sodium and potassium excretion and risk of cardiovascular events and mortality in patients with cardiovascular disease.

BACKGROUND: Most evidence on the relationship between sodium and potassium intake and cardiovascular disease originated from general population studies. This study aimed to evaluate the relation between estimated 24-hour sodium and potassium urinary excretion and the risk of recurrent vascular events and mortality in patients with vascular disease. METHODS: 7561 patients with vascular disease enrolled in the UCC-SMART cohort (1996-2015) were included. Twenty-four hour sodium and potassium urinary excretion were estimated (Kawasaki formulae) from morning urine samples. Cox proportional hazard models with restricted cubic splines were used to evaluate the relation between estimated urinary salt excretion and major adverse cardiovascular events (MACE; including myocardial infarction, stroke, cardiovascular mortality) and all-cause mortality. RESULTS: After a median follow-up of 7.4 years (interquartile range: 4.1-11.0), the relations between estimated 24-hour sodium urinary excretion and outcomes were J-shaped with nadirs of 4.59 gram/day for recurrent MACE and 4.97 gram/day for all-cause mortality. The relation between sodium-to-potassium excretion ratio and outcomes were also J-shaped with nadirs of 2.71 for recurrent MACE and 2.60 for all-cause mortality. Higher potassium urinary excretion was related to an increased risk of both recurrent MACE (HR 1.25 per gram potassium excretion per day; 95%CI 1.13-1.39) and all cause-mortality (HR 1.13 per gram potassium excretion per day; 95%CI 1.03-1.25). CONCLUSIONS: In patients with established vascular disease, lower and higher sodium intake were associated with higher risk of recurrent MACE and all-cause mortality. Higher estimated 24-hour potassium urinary excretion was associated with a higher risk of recurrent MACE and all-cause mortality.

Apparent treatment resistant hypertension and the risk of recurrent cardiovascular events and mortality in patients with established vascular disease.

AIM: To quantify the relation between apparent treatment resistant hypertension (aTRH) and the risk of recurrent major adverse cardiovascular events (MACE including stroke, myocardial infarction and vascular death) and mortality in patients with stable vascular disease. METHODS: 7455 hypertensive patients with symptomatic vascular disease were included from the ongoing UCC-SMART cohort between 1996 and 2019. aTRH was defined as an office blood pressure ≥140/90 mmHg despite treatment with ≥3 antihypertensive drugs including a diuretic. Cox proportional hazard models were used to quantify the relation between aTRH and the risk of recurrent MACE and all-cause mortality. In addition, survival for patients with aTRH was assessed, taking competing risk of non-vascular mortality into account. RESULTS: A total of 1557 MACE and 1882 deaths occurred during a median follow-up of 9.0 years (interquartile range 4.8-13.1 years). Compared to patients with non-aTRH, the 614 patients (8%) with aTRH were at increased risk of cardiovascular mortality (HR 1.27; 95% CI 1.03-1.56) and death from any cause (HR 1.25; 95% CI 1.07-1.45) but not recurrent MACE (HR 1.13; 95% CI 0.95-1.34). At the age of 50 years, patients with aTRH after a first cardiovascular event on average had a 6.4 year shorter median life expectancy free of recurrent MACE than patients with non-aTRH. CONCLUSION: In hypertensive patients with clinically manifest vascular disease, aTRH is related to a higher risk of vascular death and death from any cause. Moreover, patients with aTRH after a first cardiovascular event have a 6.4 year shorter median life expectancy free of recurrent cardiovascular disease.

Plasma Trough Concentrations of Antihypertensive Drugs for the Assessment of Treatment Adherence: A Meta-Analysis.

Biochemical drug screening by liquid chromatography-tandem mass spectrometry in plasma is an accurate method for the quantification of plasma concentrations of antihypertensive medications in patients with hypertension. Trough concentrations could possibly be used as drug-specific cutoff values in the biochemical assessment of (non-)adherence. We performed a literature review and meta-analysis of pharmacokinetic studies to determine plasma trough concentrations of amlodipine, hydrochlorothiazide, and valsartan. PubMed was searched for pharmacokinetic studies up to September 2020. Eligible studies reported steady-state mean trough concentration and their variance. Pooled trough concentrations were estimated using a three-level random effects meta-analytic model. Moderator analyses were performed to explore sources of heterogeneity. One thousand three hundred eighteen potentially relevant articles were identified of which 45 were eligible for inclusion. The pooled mean trough concentration was 9.2 ng/mL (95% CI, 7.5-10.8) for amlodipine, 41.0 ng/mL (95% CI, 17.4-64.7) for hydrochlorothiazide, and 352.9 ng/mL (95% CI, 243.5-462.3) for valsartan. Substantial heterogeneity was present for all 3 pooled estimates. Moderator analyses identified dosage as a significant moderator for the pooled trough concentration of amlodipine (ß1=0.9; P<0.05), mean age, and mean body weight for the mean trough concentration of hydrochlorothiazide (ß1=2.2, P<0.05, respectively, ß1=-4.0, P<0.05) and no significant moderators for valsartan. Plasma trough concentrations of amlodipine, hydrochlorothiazide, and valsartan, measured with liquid chromatography-tandem mass spectrometry, are highly heterogeneous over the different studies. Use of the pooled trough concentration as a cutoff in the biochemical assessment of adherence can result in inaccurate diagnosis of (non-)adherence, which may seriously harm the patient-physician relationship, and is therefore not recommended.