Sleep-time ambulatory blood pressure as a prognostic marker of vascular and other risks and therapeutic target for prevention by hypertension chronotherapy: Rationale and design of the Hygia Project

Critical appraisal of recent translational chronopharmacology and chronotherapeutic reviews, meta-analyses, and pragmatic patient trials discloses significant deficiencies of design and conduct and suspect findings

The conduct of molecular and laboratory animal circadian rhythm research has increased exponentially in the past few decades, such that today investigations are being performed by scientists of many diverse disciplines. Knowledge gained from past works is now being explored for translational applications to clinical medicine, often termed "circadian medicine," through the implementation of patient trials. However, these trials are being led, more often than not, by investigators who have little or no formal training and in-depth expertise in the methods of human circadian rhythm research, causing them to be deficient in design and produce dubious findings that have already led to unnecessary medical controversy at the expense of advances in patient care. Evidence of the very significant shortcomings of today's translational circadian medicine research is exemplified in two recent publications in well-read reputable medical journals concerning the chronotherapy of blood pressure (BP) medications: one a review and meta-analysis by Maqsood et al. published in the journal Hypertension in 2023 that pertains to ingestion-time differences in the extent of BP reduction exerted by hypertensive medications and the other a report by Mackenzie et al. in the journal Lancet in 2022 that details the results of the pragmatic TIME study that assessed ingestion-time differences in cardiovascular disease outcomes. Herein, we appraise the inaccurate trial selection, lack of quality assessment, and the numerous other shortcomings that culminated in suspect findings and faulty conclusions of the former, as well as the deficiencies in design and conduct of the latter using as reference the eight items identified in 2021 by a working committee of the International Society for Chronobiology and American Association for Medical Chronobiology and Chronotherapeutics as being necessary for high-quality research of circadian rhythm-dependencies of the therapeutic effects of BP-lowering medications. The TIME study when rated for its quality according to the extent to which its investigational methods satisfy all of the eight recommended items attains a very low overall score of + 1 out of a possible range of -1 to + 7. Moreover, our review of the methods of the currently ongoing pragmatic BedMed trial discloses major deficiencies of the same sort rending a poor quality score of + 0.5. Although the focus of this article is the appraisal of the quality of contemporary circadian medicine hypertension chronotherapy research, it additionally exposes the inadequacies and dubious quality of the critique of such manuscripts submitted for publication to influential journals, in that some peer reviewers might also be deficient in the knowledge required to properly rate their merit.

Circadian rhythms of risk factors and management in atherosclerotic and hypertensive vascular disease: Modern chronobiological perspectives of an ancient disease

Atherosclerosis, a chronic inflammatory disease of the arteries that appears to have been as prevalent in ancient as in modern civilizations, is predisposing to life-threatening and life-ending cardiac and vascular complications, such as myocardial and cerebral infarctions. The pathogenesis of atherosclerosis involves intima plaque buildup caused by vascular endothelial dysfunction, cholesterol deposition, smooth muscle proliferation, inflammatory cell infiltration and connective tissue accumulation. Hypertension is an independent and controllable risk factor for atherosclerotic cardiovascular disease (CVD). Conversely, atherosclerosis hardens the arterial wall and raises arterial blood pressure. Many CVD patients experience both atherosclerosis and hypertension and are prescribed medications to concurrently mitigate the two disease conditions. A substantial number of publications document that many pathophysiological changes caused by atherosclerosis and hypertension occur in a manner dependent upon circadian clocks or clock gene products. This article reviews progress in the research of circadian regulation of vascular cell function, inflammation, hemostasis and atherothrombosis. In particular, it delineates the relationship of circadian organization with signal transduction and activation of the renin-angiotensin-aldosterone system as well as disturbance of the sleep/wake circadian rhythm, as exemplified by shift work, metabolic syndromes and obstructive sleep apnea (OSA), as promoters and mechanisms of atherogenesis and risk for non-fatal and fatal CVD outcomes. This article additionally updates advances in the clinical management of key biological processes of atherosclerosis to optimally achieve suppression of atherogenesis through chronotherapeutic control of atherogenic/hypertensive pathological sequelae.

Update on trials examining effects of night-time blood pressure lowering drug treatment on prevention of cardiovascular disease

Current evidence on benefits of night-time blood pressure (BP) lowering drug treatment on cardiovascular disease (CVD) prevention attributable to the Ambulatory Blood Pressure Monitoring in the Prediction of Cardiovascular Events and Effects of Chronotherapy (MAPEC) trial and Bedtime hypertension treatment improves cardiovascular risk reduction (Hygia) trials has raised concern on their validity and methodology. In this commentary, the authors have updated the progress of the ongoing trials that were planned to examine the effect of night-time BP lowering drug treatment on CVD prevention. As compared to MAPEC and Hygia trials, three pragmatic trials the Blood Pressure Medication Timing (BPMedtime) trial (US), the Treatment In Morning versus Evening (TIME) trial (UK), Bedmed and Bedmed-frail (Canada) were planned without ambulatory BP monitoring. The BPMedtime trial was stopped after the pilot phase due to underestimated sample size and insufficient funds. TIME trial (UK) had a similar issue when changing the sample size from 10,269 to more than 20,000 participants. The TIME trial was completed and the initial results showing that protection against heart attack, stroke and vascular death is not affected by whether antihypertensive medications are taken in the morning or evening. The full study of the TIME trial is published in December 2022. Bedmed and Bedmed-frail trials are ongoing and will be completed in 2023. Time of taking BP lowering drug should be determined by patients at their convenience to improve the adherence. There was no difference in adverse effects of taking BP lowering drugs at night or morning. Evidence on the effect of night-time treatment on CVD events is inconsistent. The results from ongoing trials in Canada will contribute evidence to the use of BP lowering drug treatment for the prevention of CVD.

Nocturnal Hypertension in Children With Chronic Kidney Disease Is Common and Associated With Progression to Kidney Replacement Therapy

BACKGROUND

Nocturnal hypertension is a risk factor for chronic kidney disease (CKD) progression among adults. In children, effects of nocturnal hypertension on CKD progression is less studied.

METHODS

We investigated the relationships between nocturnal, daytime, or sustained hypertension and progression to kidney replacement therapy in children using Cox proportional hazards models. Nocturnal and diurnal hypertension respectively defined as: mean blood pressure >95th percentile and/or load >25% for either systolic or diastolic blood pressure within sleep or wake periods.

RESULTS

One thousand five hundred seventy-seven ambulatory blood pressure monitoring studies from 701 CKiD participants were reviewed. Nighttime, daytime, and both types of hypertension were 19%, 7%, and 33%, respectively. Participants with both daytime and nocturnal hypertension had the highest risk of kidney replacement therapy. Among children with CKD, compared with those who were normotensive, those with isolated nocturnal hypertension had a hazard ratio of 1.49 ([CI, 0.97-2.28]; P=0.068) while those with both daytime and nocturnal hypertension had a HR of 2.23 ([CI, 1.60-3.11]; P<0.001) when adjusted for age, race, sex, and baseline proteinuria and glomerular filtration. Estimates for risk were similar among glomerular and nonglomerular participants but not significant in glomerular due to smaller sample size.

CONCLUSIONS

The presence of both daytime and nocturnal hypertension is significantly associated with risk of kidney replacement therapy. Our study confirms the utility of ambulatory blood pressure monitoring in children with CKD. Identifying and controlling both daytime and nocturnal hypertension using ambulatory blood pressure monitoring may improve outcomes and delay CKD progression in this population.

Understanding Circadian Mechanisms of Sudden Cardiac Death: A Report From the National Heart, Lung, and Blood Institute Workshop, Part 2: Population and Clinical Considerations

Sudden cardiac death (SCD) is the sudden, unexpected death due to abrupt loss of heart function secondary to cardiovascular disease. In certain populations living with cardiovascular disease, SCD follows a distinct 24-hour pattern in occurrence, suggesting day/night rhythms in behavior, the environment, and endogenous circadian rhythms result in daily spans of increased vulnerability. The National Heart, Lung, and Blood Institute convened a workshop, Understanding Circadian Mechanisms of Sudden Cardiac Death to identify fundamental questions regarding the role of the circadian rhythms in SCD. Part 2 summarizes research gaps and opportunities in the areas of population and clinical research identified in the workshop. Established research supports a complex interaction between circadian rhythms and physiological responses that increase the risk for SCD. Moreover, these physiological responses themselves are influenced by several biological variables, including the type of cardiovascular disease, sex, age, and genetics, as well as environmental factors. The emergence of new noninvasive biotechnological tools that continuously measure key cardiovascular variables, as well as the identification of biomarkers to assess circadian rhythms, hold promise for generating large-scale human data sets that will delineate which subsets of individuals are most vulnerable to SCD. Additionally, these data will improve our understanding of how people who suffer from circadian disruptions develop cardiovascular diseases that increase the risk for SCD. Emerging strategies to identify new biomarkers that can quantify circadian health (eg, environmental, behavioral, and internal misalignment) may lead to new interventions and therapeutic targets to prevent the progression of cardiovascular diseases that cause SCD.

Diagnosis and treatment of arterial hypertension 2021

In the last 4 years, several evidence-based, national, and international guidelines on the management of arterial hypertension have been published, mostly with concordant recommendations, but in some aspects with discordant opinions. This in-depth review takes these guidelines into account but also addresses several new data of interest. Although being somewhat obvious and simple, accurate blood pressure (BP) measurement with validated devices is the cornerstone of the diagnosis of hypertension, but out-of-office BP measurements are of crucial importance as well. Simplified antihypertensive drug treatment such as single-pill combinations enhances the adherence to medication and speeds up the process of getting into the BP target range, a goal not so far adequately respected. Recommended (single-pill) combination therapy includes diuretics as part of the first step of antihypertensive therapy, and updated analysis does not provide evidence to exclude diuretics from this first step because of the recently discussed potential risk of increasing cancer incidence. Target BP goals need to be individualized, according to comorbidities, hypertension-mediated organ damage, coexistence of cardiovascular risk factors (including age), frailty in the elderly, and individual tolerability. There are also concordant recommendations in the guidelines that an office BP between 120 and 140 mm Hg systolic and between 70 and 80 mm Hg diastolic should be achieved. The BP target of Kidney Disease: Improving Global Outcomes for hypertensive patients with chronic kidney disease are not applicable for clinical practice because they heavily rely on 1 study that used a study-specific, nontransferable BP measurement technique and excluded the most common cause of chronic kidney disease, namely, diabetic nephropathy. Actual data even from a prospective trial on chronotherapy have to be disregarded, and antihypertensive medication should not be routinely dosed at bedtime. Rigorously conducted trials justify the revival of renal denervation for treatment of (at least, but not only) uncontrolled and treatment-resistant hypertension.

Circadian variations in blood pressure and their implications for the administration of antihypertensive drugs: is dosing in the evening better than in the morning?

: Blood pressure (BP) follows a circadian rhythm with a physiological decrease during the night. Studies have demonstrated that nocturnal BP as well as its dipping pattern during night-time have a significant prognostic importance for mortality and the occurrence of cardiovascular events. Therefore, hypertension management guidelines recommend to ascertain that patients treated for hypertension have well controlled BP values around the clock. To improve hypertension control during the night and eventually further reduce cardiovascular events, it has been proposed by some to prescribe at least one antihypertensive medication at bedtime. In this review, we have examined the data which could support the benefits of prescribing BP-lowering drugs at bedtime. Our conclusion is that there is no convincing evidence that the administration of BP-lowering drugs in the evening provides any significant advantage in terms of quality of BP control, prevention of target organ damage or reduction of cardiovascular events. Before changing practice for unproven benefits, it would be wise to wait for the results of the ongoing trials that are addressing this issue.

The effect of taking blood pressure lowering medication at night on cardiovascular disease risk. A systematic review

To investigate the effect of night-time BP-lowering drug treatment on the risk of major CVD and mortality, we systematically reviewed randomized controlled trials comparing night-time versus morning dosing. Two studies were found relevant to the clinical question (the MAPEC and Hygia trials). They were similar in study design and population and were conducted by the same study group. As the Hygia trial had more power with a significantly larger sample size, we did not perform a meta-analysis. Both studies reported a reduction of ~50% in major CVD events and all-cause mortality with night-time dosing and a reduction of 60% in CVD mortality. The results from these studies support the implementation of night-time BP-lowering drug treatment in the prevention of CVD and mortality. However there is an on-going discussion on the validity and methodology of MAPEC and Hygia trials, the interpretation of the results should be cautious. Stronger evidence is needed prior to changing clinical practice. Questions that remain to be answered relate to the generalisability of the results across different populations at different levels of BP related risk and the importance of morning versus evening timing of medication on CVD prevention as determined though a well-designed randomised controlled trial.

Chronotherapy of cardiac and vascular disease: timing medications to circadian rhythms to optimize treatment effects and outcomes

Circadian rhythms impact cardiac and vascular pathophysiology, resulting in 24-hour patterning of symptoms and life-threatening/ending events (chronopathology), plus kinetics and dynamics of medications (chronopharmacology), resulting in administration-time differences in efficacy and safety. Scheduling medications according to circadian rhythm determinants (chronotherapy) can improve treatment effects, for example, before dinner/bedtime ingestion of cholesterol-lowering medications and acetylsalicylic acid, respectively, exerts enhanced control of hypercholesterolemia and after-awakening peak of platelet aggregation; bedtime ingestion of conventional hypertension medications optimizes normalization of sleep-time blood pressure (BP)-strongest independent BP marker of cardiovascular disease (CVD) risk-and most effectively prevents (chronoprevention) CVD morbidity and mortality. Exploration of chronotherapeutic strategies to improve management of cardiac arrhythmias and vascular pathophysiology is still awaited.

Cardiovascular disease risk stratification by the Framigham score is markedly improved by ambulatory compared with office blood pressure

INTRODUCTION AND OBJECTIVES

Ambulatory blood pressure (BP) better predicts cardiovascular disease (CVD) outcomes than office BP measurements (OBPM). Nonetheless, current CVD risk stratification models continue to rely on exclusively daytime OBPM along with traditional factors, eg, age, sex, smoking, dyslipidemia, and/or diabetes.

METHODS

Data from 19 949 participants of the primary care-based Hygia Project assessed by 48-hour ambulatory BP monitoring (ABPM) and without prior CVD events were used to compare the diagnostic accuracy, discrimination, and performance of the original Framingham risk score (RS_OFG) and its adjusted version to the Hygia Project study population (RS_AFG) with that of a novel CVD risk stratification model constructed by replacing OBPM with ABPM-derived prognostic parameters (RS_ABPM).

RESULTS

During the follow-up, lasting up to 12.7 years, 1854 participants experienced a primary CVD outcome of CVD death, myocardial infarction, coronary revascularization, heart failure, stroke, transient ischemic attack, angina pectoris, or peripheral artery disease. Asleep systolic BP (SBP) mean and sleep-time relative SBP decline were the only joint significant ABPM-derived predictive factors of CVD risk and were therefore used to substitute for in-clinic SBP in the RS_ABPM model. The RS_ABPM model, in comparison with the RS_OFG and RS_AFG models, showed significantly improved calibration, diagnostic accuracy, discrimination, and performance (always P<.001). The RS_AFG-derived event-probabilities of 57.3% of the participants were outside the 95% confidence limits of the event probability determined by the RS_ABPM model.

CONCLUSIONS

These collective findings reveal important limitations of CVD risk stratification when based upon OBPM, as in the Framingham score, and corroborate the clinical value of around-the-clock ABPM to properly diagnose true hypertension and reliably stratify CVD vulnerability.

Ambulatory blood pressure-based inclusion criteria in the Hygia Chronotherapy Trial. Rebuttal to Lemmer and Middeke

The purpose of this communication is to respond to the continuing invalid criticism by Lemmer and Middeke of the MAPEC and Hygia Chronotherapy Trial by emphasizing the: (i) already unambiguously reported ambulatory blood pressure monitoring (ABPM)-based definition of hypertension utilized as the inclusion criterion of both investigations and (ii) impact of bedtime hypertension chronotherapy on ABPM-assessed parameters and cardiovascular disease (CVD) outcome for participants further categorized by influential markers of CVD risk. In so doing, we call attention to apparent unethical misconduct of Lemmer and Middeke of multiple duplicated publications of the very same unfounded criticisms.

Current evidence on the circadian-time-dependent effects of hypertension medications and their combinations in relation to findings of MAPEC and Hygia Chronotherapy Trial

The main purpose of this commentary is to update, based on our extensive review of the published literature of the past 45 yrs, the differential therapeutic effects of hypertension medications of various classes and their combinations when ingested in the evening/at-bedtime versus in the morning/upon-awakening. Interestingly, revision of the currently available evidence on the differential circadian-time-dependent effects of hypertension medications of six different classes and their combinations indicates among the 137 published hypertension medication trials that evaluated blood pressure (BP)-lowering efficacy according to treatment-time, 112 (81.75%) documented significant better benefits by evening/bedtime compared to morning/awakening-scheduled therapy. The remaining 25 published trials found no treatment-time difference in effects; indeed, no single study has reported better benefits of the still conventional, but scientifically unjustified, morning than evening/at-bedtime treatment scheme.

New perspectives on the definition, diagnosis, and treatment of true arterial hypertension

INTRODUCTION

Office blood pressure measurements (OBPM), still used today for diagnosis and management of hypertension, fail to reveal clinically important features of the mostly predictable blood pressure (BP) 24 h pattern, and lead to >45% of individuals being misclassified. Current hypertension guidelines do not provide recommendation on when-to-treat, despite multiple prospective clinical trials documenting improved normalization of 24 h BP pattern and significant reduction in cardiovascular disease (CVD) events when hypertension medications are ingested at bedtime rather than upon waking.

AREAS COVERED

In this review, the authors discuss current evidence on the: (i) most relevant attributes of the 24 h BP pattern deterministic of CVD risk; (ii) asleep systolic BP (SBP) mean as the most significant therapeutic target for CVD risk reduction; (iii) ingestion-time differences in pharmacodynamics of BP-lowering medications as reported with high consistency in multiple clinical trials; and (iv) enhanced prevention of CVD events achieved by bedtime hypertension chronotherapy.

EXPERT OPINION

Several prospective trials consistently document asleep SBP mean and sleep-time relative SBP decline (dipping) constitute highly significant CVD risk factors, independent of OBPM. Bedtime, compared to customary upon-waking, hypertension chronotherapy reduces risk of major CVD events. Collectively, these findings call for new definition of true hypertension and, accordingly, its proper diagnosis and management.

QTc Interval Predicts Disturbed Circadian Blood Pressure Variation

Background

The relationship between electrocardiographic evaluation and circadian blood pressure (BP) variation in young and middle-aged hypertensive patients remains unknown.

Methods

A total of 171 hypertensive patients were included in the study. First, patients were divided into a young and middle-aged group and an elderly group. The two groups were then separately classified into three subgroups on the basis of circadian variation of BP as dippers, non-dippers and reverse-dippers. The electrocardiographic evaluation was calculated from 12-lead electrocardiography (ECG).

Results

QTc intervals were shortest in the dippers and longest in the reverse-dippers in the young and middle-aged group (QTc dipper: 416.53±18.37ms; non-dipper: 438.30±29.71ms; reverse-dipper: 444.93±25.47ms; for dipper vs non-dipper, and dipper vs reverse-dipper P<0.05). QTc interval was found to be an independent risk factor for the non-dipper BP pattern (Odds ratio 1.049; 95% CI 1.01-1.089; P=0.012) and reverse-dipper BP pattern (Odds ratio 1.051; 95% CI 1.007-1.098; P=0.023) in young and middle-aged hypertensive patients. No significant differences in other ECG parameters were found among the three subgroups in the young and middle-aged group.

Conclusion

Our study suggested that QTc interval might serve as a risk factor for non-dipper BP pattern and reverse-dipper BP pattern in young and middle-aged hypertensive patients.

Greater natriuretic response to ENaC inhibition in male versus female Sprague-Dawley rats

Genes for the epithelial sodium channel (ENaC) subunits are expressed in a circadian manner, but whether this results in time-of-day differences in activity is not known. Recent data show that protein expression of ENaC subunits is higher in kidneys from female rats, yet females are more efficient in excreting an acute salt load. Thus, our in vivo study determined whether there is a time-of-day difference as well as a sex difference in the response to ENaC inhibition by benzamil. Our results showed that the natriuretic and diuretic responses to a single dose of benzamil were significantly greater in male compared with female rats whether given at the beginning of the inactive period [Zeitgeber time 0 (ZT0), 7 AM] or active period (ZT12, 7 PM). However, the response to benzamil was not significantly different between ZT0 and ZT12 dosing in either male or female rats. There was no difference in renal cortical α-ENaC protein abundance between ZT0 and ZT12 or males and females. Given previous reports of flow-induced stimulation of endothelin-1 (ET-1) production and sex differences in the renal endothelin system, we measured urinary ET-1 excretion to assess the effects of increased urine flow on intrarenal ET-1. ET-1 excretion was significantly increased following benzamil administration in both sexes, but this increase was significantly greater in females. These results support the hypothesis that ENaC activity is less prominent in maintaining Na⁺ balance in females independent of renal ET-1. Because ENaC subunit genes and protein expression vary by time of day and are greater in female rat kidneys, this suggests a clear disconnect between ENaC expression and channel activity.

Asleep blood pressure: significant prognostic marker of vascular risk and therapeutic target for prevention

Aims

Sleep-time blood pressure (BP) is a stronger risk factor for cardiovascular disease (CVD) events than awake and 24 h BP means, but the potential role of asleep BP as therapeutic target for diminishing CVD risk is uncertain. We investigated whether CVD risk reduction is most associated with progressive decrease of either office or ambulatory awake or asleep BP mean.

Methods and results

We prospectively evaluated 18 078 individuals with baseline ambulatory BP ranging from normotension to hypertension. At inclusion and at scheduled visits (mainly annually) during follow-up, ambulatory BP was measured for 48 consecutive hours. During the 5.1-year median follow-up, 2311 individuals had events, including 1209 experiencing the primary outcome (composite of CVD death, myocardial infarction, coronary revascularization, heart failure, and stroke). The asleep systolic blood pressure (SBP) mean was the most significant BP-derived risk factor for the primary outcome [hazard ratio 1.29 (95% CI) 1.22-1.35 per SD elevation, P < 0.001], regardless of office [1.03 (0.97-1.09), P = 0.32], and awake SBP [1.02 (0.94-1.10), P = 0.68]. Most important, the progressive attenuation of asleep SBP was the most significant marker of event-free survival [0.75 (95% CI 0.69-0.82) per SD decrease, P < 0.001], regardless of changes in office [1.07 (0.97-1.17), P = 0.18], or awake SBP mean [0.96 (0.85-1.08), P = 0.47] during follow-up.

Conclusion

Asleep SBP is the most significant BP-derived risk factor for CVD events. Furthermore, treatment-induced decrease of asleep, but not awake SBP, a novel hypertension therapeutic target requiring periodic patient evaluation by ambulatory monitoring, is associated with significantly lower risk for CVD morbidity and mortality.

Bedtime hypertension treatment improves cardiovascular risk reduction: the Hygia Chronotherapy Trial

Aims

The Hygia Chronotherapy Trial, conducted within the clinical primary care setting, was designed to test whether bedtime in comparison to usual upon awakening hypertension therapy exerts better cardiovascular disease (CVD) risk reduction.

Methods and results

In this multicentre, controlled, prospective endpoint trial, 19 084 hypertensive patients (10 614 men/8470 women, 60.5 ± 13.7 years of age) were assigned (1:1) to ingest the entire daily dose of ≥1 hypertension medications at bedtime (n = 9552) or all of them upon awakening (n = 9532). At inclusion and at every scheduled clinic visit (at least annually) throughout follow-up, ambulatory blood pressure (ABP) monitoring was performed for 48 h. During the 6.3-year median patient follow-up, 1752 participants experienced the primary CVD outcome (CVD death, myocardial infarction, coronary revascularization, heart failure, or stroke). Patients of the bedtime, compared with the upon-waking, treatment-time regimen showed significantly lower hazard ratio—adjusted for significant influential characteristics of age, sex, type 2 diabetes, chronic kidney disease, smoking, HDL cholesterol, asleep systolic blood pressure (BP) mean, sleep-time relative systolic BP decline, and previous CVD event—of the primary CVD outcome [0.55 (95% CI 0.50–0.61), P &lt; 0.001] and each of its single components (P &lt; 0.001 in all cases), i.e. CVD death [0.44 (0.34–0.56)], myocardial infarction [0.66 (0.52–0.84)], coronary revascularization [0.60 (0.47–0.75)], heart failure [0.58 (0.49–0.70)], and stroke [0.51 (0.41–0.63)].

Conclusion

Routine ingestion by hypertensive patients of ≥1 prescribed BP-lowering medications at bedtime, as opposed to upon waking, results in improved ABP control (significantly enhanced decrease in asleep BP and increased sleep-time relative BP decline, i.e. BP dipping) and, most importantly, markedly diminished occurrence of major CVD events.

Trial registration

ClinicalTrials.gov, number NCT00741585.

 

Diagnosis and management of hypertension: around-the-clock ambulatory blood pressure monitoring is substantially more effective and less costly than daytime office blood pressure measurements

The cost-effectiveness of ambulatory blood pressure (BP) monitoring (ABPM) versus traditional office BP measurement (OBPM) for the diagnosis and management of hypertension has been evaluated only by few studies and based solely on the reduction of medical care expenses through avoiding treatment of isolated-office hypertension. Data from the 21963 participants in the Hygia Project, a multicenter outcomes study that incorporates into routine primary care periodic, at least yearly, 48 h ABPM evaluation, were utilized to assess the cost-effectiveness - relative to vascular pathology expenditures countrywide in Spain - of ABPM versus OBPM. The actual reported Spanish healthcare expenditure for vascular pathology in 2015 - aggregate costs of medical examinations, outpatient and inpatient care, therapeutic interventions, plus non-healthcare services (productivity losses due to morbidity/mortality and informal family/friends-provided care) - was used to compare yearly costs when diagnostic and treatment decisions for hypertension are based on the OBPM versus the ABPM-model. Our economic analysis is based on the more realistic and feasible approach of restricting ABPM solely to high-risk individuals of age ≥60 years and/or with diabetes, chronic kidney disease, and/or previous cardiovascular event, who in the Hygia Project accounted for >90% of all documented events. The projected net benefit countrywide in favor of the proposed ABPM-model is ~5294M€/year, i.e., 360.33€/year (95%CI [347.52-374.85]) per ABPM-evaluated person. This highly conservative economic analysis indicates ABPM is a much more cost-effective strategy than repeated OBPM not only for accurate diagnosis and management of true hypertension but marked reduction of expenditures on elevated BP-associated vascular pathology.

The potential role of testosterone in hypertension and target organ damage in hypertensive postmenopausal women

Objective: The aim of this study was to confirm the potential role of testosterone in hypertension and target organ damage (TOD) in hypertensive postmenopausal women.

Methods: A matched group study was conducted. One hundred sixty-one hypertensive postmenopausal women between 45 and 65 years of age were enrolled as group 1. Another 161 age-matched hypertensive men were enrolled as group 2. Ambulatory blood pressure monitoring, echocardiographic imaging, vascular function, sex hormones and clinical characteristics were evaluated. Quantitative data were analyzed using independent Student’s t-test and multiple regression analysis.

Results: The mean and load level of blood pressure were lower in women than in men (P<0.05), except for the mean level and load of the nocturnal systolic blood pressure (SBP) (123.77±15.72 mmHg vs 126.35±15.64 mmHg, and 50.43±30.31% vs 55.35±28.51%, P>0.05). However, the carotid-femoral pulse wave velocity (cf-PWV) in women was higher than that in men (9.68±2.23 m/s vs 8.03±2.82 m/s, P<0.05). The ratio of the early diastolic mitral peak flow velocity to early diastolic mitral annular velocity (E/Em) was obviously impaired (13.06±3.53 vs 12.05±3.68, P<0.05) in women. Furthermore, in women, a positive correlation was found between testosterone and cf-PWV (γ=0.157, P=0.046), and Cf-PWV was positively related to the mean level of nighttime SBP (γ=0.210, P=0.008). Moreover, nocturnal SBP was a risk factor for E/Em (γ=0.156, P=0.048, P<0.05).

Conclusion: Testosterone may play a role in the correlation between hypertension and TOD in hypertensive postmenopausal women.

Clinical Trial number: This research study was registered under the ClinicalTrials.gov PRS Website (NCT03451747).

Chronobiology in nephrology: the influence of circadian rhythms on renal handling of drugs and renal disease treatment

INTRODUCTION

Chronobiology studies the phenomenon of rhythmicity in living organisms. The circadian rhythms are genetically determined and regulated by external synchronizers (the daylight cycle). Several biological processes involved in the pharmacokinetics and pharmacodynamics of drugs are subjected to circadian variations. Chronopharmacology studies how biological rhythms influence pharmacokinetics, pharmacodynamics, and toxicity, and determines whether time-of-day administration modifies the pharmacological characteristics of the drug. Chronotherapy applies chronopharmacological studies to clinical treatments, determining the best biological time for dosing: when the beneficial effects are maximal and the incidence and/or intensity of related side effects and toxicity are minimal. Most water-soluble drugs or drug metabolites are eliminated by urine through the kidney. The rate of drug clearance in the urine depends on several intrinsic variables related to renal function including renal blood flow, glomerular filtration rate, the ability of the kidney to reabsorb or to secrete drugs, urine flow, and urine pH, which influences the degree of urine acidification. Curiously, all these variables present a circadian behavior in different mammalian models.

CONCLUSION

The circadian rhythms have influence in the renal physiology, pathophysiology, and pharmacology, and these data should be taken into account in clinical nephrology practice.

Chronotherapy for Hypertension

PURPOSE OF REVIEW

Given the emerging knowledge that circadian rhythmicity exists in every cell and all organ systems, there is increasing interest in the possible benefits of chronotherapy for many diseases. There is a well-documented 24-h pattern of blood pressure with a morning surge that may contribute to the observed morning increase in adverse cardiovascular events. Historically, antihypertensive therapy involves morning doses, usually aimed at reducing daytime blood pressure surges, but an absence of nocturnal dipping blood pressure is also associated with increased cardiovascular risk.

RECENT FINDINGS

To more effectively reduce nocturnal blood pressure and still counteract the morning surge in blood pressure, a number of studies have examined moving one or more antihypertensives from morning to bedtime dosing. More recently, such studies of chronotherapy have studied comorbid populations including obstructive sleep apnea, chronic kidney disease, or diabetes. Here, we summarize major findings from recent research in this area (2013-2017). In general, nighttime administration of antihypertensives improved overall 24-h blood pressure profiles regardless of disease comorbidity. However, inconsistencies between studies suggest a need for more prospective randomized controlled trials with sufficient statistical power. In addition, experimental studies to ascertain mechanisms by which chronotherapy is beneficial could aid drug design and guidelines for timed administration.

RECENT ADVANCES IN UNDERSTANDING THE CIRCADIAN CLOCK IN RENAL PHYSIOLOGY

Accumulating evidence suggests a critical role for the molecular circadian clock in the regulation of renal function. Here, we consider the most recent advances in our understanding of the relationship between the circadian clock and renal physiology.

Hypertension: New perspective on its definition and clinical management by bedtime therapy substantially reduces cardiovascular disease risk

Diagnosis of hypertension-elevated blood pressure (BP) associated with increased cardiovascular disease (CVD) risk-and its management for decades have been based primarily on single time-of-day office BP measurements (OBPM) assumed representative of systolic (SBP) and diastolic BP (DBP) during the entire 24-hours span. Around-the-clock ambulatory blood pressure monitoring (ABPM), however, reveals BP undergoes 24-hours patterning characterized in normotensives and uncomplicated hypertensives by striking morning-time rise, 2 daytime peaks-one ~2-3 hours after awakening and the other early evening, small midafternoon nadir and 10-20% decline (BP dipping) in the asleep BP mean relative to the wake-time BP mean. A growing number of outcome trials substantiate correlation between BP and target organ damage, vascular and other risks is greater for the ABPM-derived asleep BP mean, independent and stronger predictor of CVD risk, than daytime OBPM or ABPM-derived awake BP. Additionally, bedtime hypertension chronotherapy, that is, ingestion of ≥1 conventional hypertension medications at bedtime to achieve efficient attenuation of asleep BP, better reduces total CVD events by 61% and major events (CVD death, myocardial infarction, ischaemic and haemorrhagic stroke) by 67%-even in more vulnerable chronic kidney disease, diabetes and resistant hypertension patients-than customary on-awaking therapy that targets wake-time BP. Such findings of around-the-clock ABPM and bedtime hypertension outcome trials, consistently indicating greater importance of asleep BP than daytime OBPM or ambulatory awake BP, call for a new definition of true arterial hypertension plus modern approaches for its diagnosis and management.

Risk of incident chronic kidney disease is better reduced by bedtime than upon-awakening ingestion of hypertension medications

This trial investigated whether therapy with the entire daily dose of ≥1 hypertension medications at bedtime exerts a greater reduction in the risk of incident chronic kidney disease (CKD) than therapy with all medications upon awakening. We conducted a prospective, open-label, blinded endpoint trial of 2078 hypertensive patients without CKD (1017 men/1061 women, 53.6 ± 13.7 years of age) randomized to ingest all their prescribed hypertension medications upon awakening (n = 1041) or the entire daily dose of ≥1 of those medications at bedtime (n = 1037). During a 5.9-year median follow-up, 368 participants developed CKD. Patients of the bedtime, compared with the morning, treatment group showed (i) significantly lower asleep blood pressure (BP) mean, greater sleep-time relative BP decline, and attenuated prevalence of non-dipping at the final evaluation (38 vs. 55%; P < 0.001); and (ii) a significantly lower hazard ratio of CKD, adjusted for the significant influential characteristics of age, serum creatinine, urinary albumin, type 2 diabetes, previous cardiovascular event, asleep systolic BP mean, and sleep-time relative systolic BP decline (0.27 (95% confidence interval: 0.21-0.36); event-rate 8.3 vs. 27.1% in the bedtime and morning-treatment groups; P < 0.001). Greater benefit was observed for bedtime than awakening treatment, with angiotensin converting enzyme inhibitors and angiotensin receptor blockers. In hypertensive patients without CKD, ingestion of ≥1 BP-lowering medications at bedtime, mainly those modulating or blocking the effects of angiotensin II, compared with ingestion of all such medications upon-awakening, resulted in improved ambulatory BP control (significant further decrease of asleep BP and enhanced sleep-time relative BP decline) and reduced risk of incident CKD.

Blood pressure response to CPAP treatment in subjects with obstructive sleep apnoea: the predictive value of 24-h ambulatory blood pressure monitoring

The reduction in blood pressure (BP) with continuous positive airway pressure (CPAP) is modest and highly variable. In this study, we identified the variables that predict BP response to CPAP.

24-h ambulatory BP monitoring (ABPM), C-reactive protein (CRP), leptin, adiponectin and 24-h urinary catecholamine were measured before and after 6 months of CPAP in obstructive sleep apnoea (OSA) patients.

Overall, 88 middle-aged, obese male patients with severe OSA (median apnoea–hypopnoea index 42 events·h−1) were included; 28.4% had hypertension. 62 patients finished the study, and 60 were analysed. The daytime diastolic BP (−2 mmHg) and norepinephrine (−109.5 nmol·day-1) were reduced after CPAP, but no changes in the 24-h BP, night-time BP, dopamine, epinephrine, CRP, leptin or adiponectin were detected. The nocturnal normotension was associated with an increased night-time-BP (+4 mmHg) after CPAP, whereas nocturnal hypertension was associated with a reduction of 24-h BP (−3 mmHg). A multivariate linear regression model showed differential night-time BP changes after CPAP. Specifically, low night-time heart rate (<68 bpm) and BP dipper profile were associated with increased night-time BP and new diagnosis of nocturnal hypertension.

Our results suggest that nocturnal hypertension, circadian BP pattern and night-time heart rate could be clinical predictors of BP response to CPAP and support the usefulness of 24-h ABPM for OSA patients before treatment initiation. These results need to be confirmed in further studies.

Do night and around-the-clock firefighters' shift schedules induce deviation in tau from 24 hours of systolic and diastolic blood pressure circadian rhythms?

Systolic (S) and diastolic (D) blood pressures (BP) [SBP and DBP] are circadian rhythmic with period (τ) in healthy persons assumed to be maintained at 24.0h. We tested this assumption in a sample of 30 healthy career (mean >12 yrs) 30-to-46 yr-old male Caucasian French firefighters (FFs) categorized into three groups according to work schedule and duties: Group A - 12 FFs working 12h day, 12h night, and occasionally 24h shifts and whose primary duties are firefighting plus paramedical and road rescue services; Group B - 9 FFs working mostly 12h day and 12h night shifts and whose duties are answering incoming emergency calls and coordinating service vehicle dispatch from fire stations with Group A personnel; Group C - 9 day shift (09:00-17:00h) FFs charged with administrative tasks. SBP and DBP, both in winter and in summer studies of the same FFs, were sampled by ambulatory BP monitoring every 1h between 06:00-23:00h and every 2h between 23:01-05:59h, respectively, their approximate off-duty wake and sleep spans, for 7 consecutive days. Activity (wrist actigraphy) was also sampled at 1-min intervals. Prominent τ of each variable was derived by a power spectrum program written for unequal-interval time series data, and between-group differences in incidence of τ≠24h of FFs were assessed by chi square test. Circadian rhythm disruption (τ≠24h) of either the SBP or DBP rhythm occurred almost exclusively in night and 24h shift FFs of Group A and B, but almost never in day shift FFs of Group C, and it was not associated with altered τ from 24.0h of the circadian activity rhythm. In summer, occurrence of τ≠24 for FFs of Group A and B differed from that for FFs of Group C in SBP (p=0.042) and DBP (p=0.015); no such differences were found in winter (p>0.10). Overall, manifestation of prominent τ≠24h of SBP or DBP time series was greater in summer than winter, 27.6% versus 16.7%, when workload of Group B FFs, i.e. number of incoming emergency telephone calls, and of Group A FFs, i.e. number of dispatches for provision of emergency services, was, respectively, two and fourfold greater and number of 12h night shifts worked by Group B FFs and number of 24h shifts worked by Group A FFs was, respectively, 92% and 25% greater. FFs of the three groups exhibited no winter-summer difference in τ≠24h of SBP or SDP; however, τ≠24h of DBP in Group B FFs was more frequent in summer than winter (p=0.046). Sleep/wake cycle disruption, sleep deprivation, emotional and physical stress, artificial light-at-night, and altered nutrient timings are hypothesized causes of τ≠24h for BP rhythms of affected Groups A and B FFs, but with unknown future health effects.

Bedtime Blood Pressure Chronotherapy Significantly Improves Hypertension Management

Consistent evidence of numerous studies substantiates the asleep blood pressure (BP) mean derived from ambulatory BP monitoring (ABPM) is both an independent and a stronger predictor of cardiovascular disease (CVD) risk than are daytime clinic BP measurements or the ABPM-determined awake or 24-hour BP means. Hence, cost-effective adequate control of sleep-time BP is of marked clinical relevance. Ingestion time, according to circadian rhythms, of hypertension medications of 6 different classes and their combinations significantly improves BP control, particularly sleep-time BP, and reduces adverse effects.

Bedtime Chronotherapy with Conventional Hypertension Medications to Target Increased Asleep Blood Pressure Results in Markedly Better Chronoprevention of Cardiovascular and Other Risks than Customary On-awakening Therapy

The bases for bedtime hypertension chronotherapy (BHCT) as superior chronoprevention against cardiovascular disease (CVD) are: (1) correlation between blood pressure (BP) and various risks is greater for ambulatory BP monitoring (ABPM) than office BP measurements (OBPM); (2) asleep BP mean is a better predictor of CVD risk than ABPM awake and 24-hour means and OBPM; and (3) targeting of asleep BP by BHCT with one or more conventional medications versus usual on-awakening therapy better reduces major and total CVD events. BHCT offers the most cost-effective chronoprevention against adverse CVD outcomes in regular and vulnerable renal, diabetic, and resistant hypertensive patients.