Influence of Age and Hypertension Treatment-time on Ambulatory Blood Pressure in Hypertensive Patients

The many faces of hypertension in individuals with type 1 diabetes

Several disturbed blood pressure (BP) patterns, including disparities between office and out-of-office BP measurements (such as white-coat and masked hypertension), disturbed circadian BP variability (such as abnormal dipping patterns and nocturnal hypertension) and treatment-resistant hypertension, are common in individuals with type 1 diabetes. Consequently, office or home BP measurements alone may not reflect real BP variation and may lead to inadequate diagnosis and treatment of hypertension. The early detection of these disturbed BP patterns is especially crucial in individuals with type 1 diabetes, as these patterns may indicate future development of adverse cardiovascular and renal outcomes. In this review we will describe these disturbed BP patterns and discuss recent findings on their prevalence and outcomes. We will also address critical areas for future research to determine the true prevalence and prognosis of disturbed BP patterns, and to optimize and improve the knowledge and management of high-risk individuals with type 1 diabetes and disturbed BP patterns.

More Than Morningness: The Effect of Circadian Rhythm Amplitude and Stability on Resilience, Coping, and Sleep Duration

Self-report tools that measure circadian rhythms have focused primarily on phase. We add to the sparse literature on assessing amplitude and stability. We randomly recruited 1,163 participants who completed several measures. The correlation between the LV scale (amplitude) and FR scale (stability) was -0.12 (p < 0.01). As expected, amplitude was negatively associated with phase (r = -0.64, p < 0.01) while stability showed a weak link with phase (r = 0.07, p < 0.05). Structural equation modeling suggested a close model-fit of the factor structure in the sample (RMSEA = 0.033). The LV scale explained 22% of the variance, while the FR scale explained 23%. Scale reliability was satisfactory for the LV scale (0.68) and good for the FR scale (0.73). Participants with low amplitude or flexible rhythms reported significantly better resilience, coping, and required less daily sleep. We constructed a composite circadian categorical variable to combine the best attributes from the LV and FR scales; participants with both low amplitude and flexible rhythms, reported significantly better resilience, coping, and less sleep need. We found rhythm amplitude decreased with age, while stability remained constant.

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.

The Circadian Rhythm of Thermoregulation Modulates both the Sleep/Wake Cycle and 24 h Pattern of Arterial Blood Pressure

Borbély proposed an interacting two-component model of sleep regulation comprising a homeostatic Process S and a circadian Process C. The model has provided understanding of the association between core body temperature (CBT) as a key element of Process C that is deterministic of sleep onset and offset. However, it additionally provides a new perspective of the importance of the thermoregulatory mechanisms of Process C in modulating the circadian rhythm of arterial blood pressure (ABP). Herein, we examine the circadian physiology of thermoregulation, including at the end of the activity span the profound redistribution of cardiac output from the systemic circulation to the arteriovenous anastomoses of the glabrous skin that markedly enhances convective transfer of heat from the body to the environment to cause (i) decrease of the CBT as a pathway to sleep onset and (ii) attenuation of the asleep ABP mean and augmentation of the ABP decline (dipping) from the wake-time mean, in combination the strongest predictors of the risk for blood vessel and organ pathology and morbid and mortal cardiovascular disease events. We additionally review the means by which blood perfusion to the glabrous skin can be manipulated on demand by selective thermal stimulation, that is, mild warming, on the skin of the cervical spinal cord to intensify Process C as a way to facilitate sleep induction and promote healthy asleep ABP. © 2021 American Physiological Society. Compr Physiol 11:1-14, 2021.

Ingestion-time differences in the pharmacodynamics of hypertension medications: Systematic review of human chronopharmacology trials

Pharmacokinetics of hypertension medications is significantly affected by circadian rhythms that influence absorption, distribution, metabolism and elimination. Furthermore, their pharmacodynamics is affected by ingestion-time differences in kinetics and circadian rhythms comprising the biological mechanism of the 24 h blood pressure (BP) pattern. However, hypertension guidelines do not recommend the time to treat patients with medications. We conducted a systematic review of published evidence regarding ingestion-time differences of hypertension medications and their combinations on ambulatory BP-lowering, safety, and markers of target organ pathology. Some 153 trials published between 1976 and 2020, totaling 23,869 hypertensive individuals, evaluated 37 different single and 14 dual-fixed combination therapies. The vast (83.7%) majority of the trials report clinically and statistically significant benefits - including enhanced reduction of asleep BP without inducing sleep-time hypotension, reduced prevalence of the higher cardiovascular disease risk BP non-dipping 24 h profile, decreased incidence of adverse effects, improved renal function, and reduced cardiac pathology - when hypertension medications are ingested at-bedtime/evening rather than upon-waking/morning. Non-substantiated treatment-time difference in effects by the small proportion (16.3%) of published trials is likely explained by deficiencies of study design and conduct. Systematic and comprehensive review of the literature published the past 45 years reveals no single study reported significantly better benefit of the still conventional, yet unjustified by medical evidence, upon-waking/morning hypertension treatment schedule.

Guidelines for the design and conduct of human clinical trials on ingestion-time differences - chronopharmacology and chronotherapy - of hypertension medications

Current hypertension guidelines fail to provide a recommendation on when-to-treat, thus disregarding relevant circadian rhythms that regulate blood pressure (BP) level and 24 h patterning and medication pharmacokinetics and pharmacodynamics. The ideal purpose of ingestion-time (chronopharmacology, i.e. biological rhythm-dependent effects on the kinetics and dynamics of medications, and chronotherapy, i.e. the timing of pharmaceutical and other treatments to optimize efficacy and safety) trials should be to explore the potential impact of endogenous circadian rhythms on the effects of medications. Such investigations and outcome trials mandate adherence to the basic standards of human chronobiology research. In-depth review of the more than 150 human hypertension pharmacology and therapeutic trials published since 1974 that address the differential impact of upon-waking/morning versus at-bedtime/evening schedule of treatment reveals diverse protocols of sometimes suboptimal or defective design and conduct. Many have been "time-of-day," i.e. morning versus evening, rather than circadian-time-based, and some relied on wake-time office BP rather than around-the-clock ambulatory BP measurements (ABPM). Additionally, most past studies have been of too small sample size and thus statistically underpowered. As of yet, there has been no consensual agreement on the proper design, methods and conduct of such trials. This Position Statement recommends ingestion-time hypertension trials to follow minimum guidelines: (i) Recruitment of participants should be restricted to hypertensive individuals diagnosed according to ABPM diagnostic thresholds and of a comparable activity/sleep routine. (ii) Tested treatment-times should be selected according to internal biological time, expressed by the awakening and bed times of the sleep/wake cycle. (iii) ABPM should be the primary or sole method of BP assessment. (iv) The minimum-required features for analysis of the ABPM-determined 24 h BP pattern ought to be the asleep (not "nighttime") BP mean and sleep-time relative BP decline, calculated in reference to the activity/rest cycle per individual. (v) ABPM-obtained BP means should be derived by the so-called adjusted calculation procedure, not by inaccurate arithmetic averages. (vi) ABPM should be performed with validated and calibrated devices at least hourly throughout two or more consecutive 24 h periods (48 h in total) to achieve the highest reproducibility of mean wake-time, sleep-time and 48 h BP values plus the reliable classification of dipping status. (vii) Calculation of minimum required sample size in adherence with proper statistical methods must be provided. (viii) Hypertension chronopharmacology and chronotherapy trials should preferably be randomized double-blind, randomized open-label with blinded-endpoint, or crossover in design, the latter with sufficient washout period between tested treatment-time regimens.

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.

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.

Cultural factors and the circadian rhythm of ST elevation myocardial infarction in patients in a Mediterranean island

INTRODUCTION

The circadian rhythm of onset of myocardial infarction shows an increased risk during the morning hours. However, it is not clear whether habits, culture and sunshine hours differentiate circadian rhythm. The aim of this study was to investigate the influence of cultural factors on the circadian rhythm of acute myocardial infarction with ST segment elevation in a Mediterranean island.

METHOD

The study was a retrospective correlational survey. It included 123 patients with ST elevation myocardial infarction (mean age 60.7±12.6; 82% men). The 24 h of a day were divided into four six-hour periods of time for study purposes (00:01-06:00; 06:01-12:00; 12:01-18:00; and 18:01-24:00) and the chi-square test was used for the analysis.

RESULTS

A morning peak of symptoms onset of ST-elevation myocardial infarction was detected during the period 06:01-12:00 (p=0.044). In patients who were smokers, a bimodal pattern involving a morning (06:01-12:00) and an afternoon-to-night peak (18:01-24:00) (p=0.005) was detected. For patients with a history of hypertension, a morning peak of their symptoms was also detected (p=0.028). Different circadian variations were found between patients over the age of 60 years old and patients under the age of 60 years old (p=0.025).

CONCLUSIONS

Patients with ST elevation myocardial infarction seem to follow a circadian rhythm with a peak of onset of symptoms in the morning. In the smokers' subgroup, a different circadian pattern was found. The habit of smoking is likely to affect the circadian rhythm of the onset of ST elevation myocardial infarction in the Mediterranean area and culture.

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.

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.

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.

Circadian disruption: New clinical perspective of disease pathology and basis for chronotherapeutic intervention

Biological processes are organized in time as innate rhythms defined by the period (τ), phase (peak [Φ] and trough time), amplitude (A, peak-trough difference) and mean level. The human time structure in its entirety is comprised of ultradian (τ < 20 h), circadian (20 h > τ < 28 h) and infradian (τ > 28 h) bioperiodicities. The circadian time structure (CTS) of human beings, which is more complicated than in lower animals, is orchestrated and staged by a brain central multioscillator system that includes a prominent pacemaker - the suprachiasmatic nuclei of the hypothalamus. Additional pacemaker activities are provided by the pineal hormone melatonin, which circulates during the nighttime, and the left and right cerebral cortices. Under ordinary circumstances this system coordinates the τ and Φ of rhythms driven by subservient peripheral cell, tissue and organ clock networks. Cyclic environmental, feeding and social time cues synchronize the endogenous 24 h clocks and rhythms. Accordingly, processes and functions of the internal environment are integrated in time for maximum biological efficiency, and they are also organized and synchronized in time to the external environment to ensure optimal performance and response to challenge. Artificial light at night (ALAN) exposure can alter the CTS as can night work, which, like rapid transmeridian displacement by air travel, necessitates realignment of the Φ of the multitude of 24 h rhythms. In 2001, Stevens and Rea coined the phrase "circadian disruption" (CD) to label the CTS misalignment induced by ALAN and shift work (SW) as a potential pathologic mechanism of the increased risk for cancer and other medical conditions. Current concerns relating to the effects of ALAN exposure on the CTS motivated us to renew our long-standing interest in the possible role of CD in the etiopathology of common human diseases and patient care. A surprisingly large number of medical conditions involve CD: adrenal insufficiency; nocturia; sleep-time non-dipping and rising blood pressure 24 h patterns (nocturnal hypertension); delayed sleep phase syndrome, non-24 h sleep/wake disorder; recurrent hypersomnia; SW intolerance; delirium; peptic ulcer disease; kidney failure; depression; mania; bipolar disorder; Parkinson's disease; Smith-Magenis syndrome; fatal familial insomnia syndrome; autism spectrum disorder; asthma; byssinosis; cancers; hand, foot and mouth disease; post-operative state; and ICU outcome. Poorly conceived medical interventions, for example nighttime dosing of synthetic corticosteroids and certain β-antagonists and cyclic nocturnal enteral or parenteral nutrition, plus lifestyle habits, including atypical eating times and chronic alcohol consumption, also can be causal of CD. Just as surprisingly are the many proven chronotherapeutic strategies available today to manage the CD of several of these medical conditions. In clinical medicine, CD seems to be a common, yet mostly unrecognized, pathologic mechanism of human disease as are the many effective chronotherapeutic interventions to remedy it.

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

This article describes the rationale, objectives, design and conduct of the ambulatory blood pressure monitoring (ABPM)-based Hygia Project. Given the substantial evidence of the significantly better prognostic value of ABPM compared to clinic BP measurements, several international guidelines now propose ABPM as a requirement to confirm the office diagnosis of hypertension. Nonetheless, all previous ABPM outcome investigations, except the Monitorización Ambulatoria para Predicción de Eventos Cardiovasculares study (MAPEC) study, relied upon only a single, low-reproducible 24 h ABPM assessment per participant done at study inclusion, thus precluding the opportunity to explore the potential reduction in cardiovascular disease (CVD) risk associated with modification of prognostic ABPM-derived parameters by hypertension therapy. The findings of the single-center MAPEC study, based upon periodic systematic 48 h ABPM evaluation of all participants during a median follow-up of 5.6 years, constitute the first proof-of-concept evidence that the progressive reduction of the asleep systolic blood pressure (SBP) mean and correction of the sleep-time relative SBP decline toward the normal dipper BP profile, most efficiently accomplished by a bedtime hypertension treatment strategy, best attenuates the risk of CVD, stroke and development of new-onset diabetes. The Hygia Project, primarily designed to extend the use of ABPM in primary care as a requirement for diagnosis of hypertension, evaluation of response to treatment and individualized assessment of CVD and other risks, is a research network presently composed of 40 clinical sites and 292 investigators. Its main objectives are to (i) investigate whether specific treatment-induced changes in ABPM-derived parameters reduce risk of CVD events, stroke, new-onset diabetes and/or development of chronic kidney disease (CKD); and (ii) test the hypothesis that bedtime chronotherapy entailing the entire daily dose of ≥1 conventional hypertension medications exerts better ambulatory BP control and CVD, metabolic and renal risk reduction than all such medications ingested in the morning upon awakening. Between 2007 and 2015, investigators recruited 18 078 persons [9769 men/8309 women, 59.1 ± 14.3 years of age (mean ± SD)], including 15 764 with hypertension according to ABPM criteria as participants in the prospective randomized chronotherapy trial. The initial evaluation includes 48 h ABPM, detailed medical history and screening laboratory blood and urine tests. The same evaluation procedure is scheduled annually, or more frequently when treatment adjustment is required for proper ambulatory BP control, targeting a median follow-up of >5 years. The primary CVD outcome end point is the composite of CVD death, myocardial infarction, coronary revascularization, heart failure, ischemic stroke and hemorrhagic stroke. The independent Hygia Project Events Committee periodically evaluates blinded clinical reports to ascertain and certify every documented event. Beyond the potential findings resulting from testing the main hypotheses, the Hygia Project has already demonstrated, as proof of concept, that the routine diagnosis of hypertension and individualized assessment of CVD and other risks by ABPM, as currently recommended, is fully viable in the primary care setting, where most people with either hypertension, dyslipidemia, type 2 diabetes or CKD receive routine medical attention.

Chronotherapy with conventional blood pressure medications improves management of hypertension and reduces cardiovascular and stroke risks

Correlation between blood pressure (BP) and target organ damage, vascular risk and long-term patient prognosis is greater for measurements derived from around-the-clock ambulatory BP monitoring than in-clinic daytime ones. Numerous studies consistently substantiate the asleep BP mean is both an independent and a much better predictor of cardiovascular disease (CVD) risk than either the awake or 24 h means. Sleep-time hypertension is much more prevalent than suspected, not only in patients with sleep disorders, but also among those who are elderly or have type 2 diabetes, chronic kidney disease or resistant hypertension. Hence, cost-effective adequate control of sleep-time BP is of marked clinical relevance. Ingestion time, according to circadian rhythms, of hypertension medications of six different classes and their combinations significantly affects BP control, particularly sleep-time BP, and adverse effects. For example, because the high-amplitude circadian rhythm of the renin-angiotensin-aldosterone system activates during nighttime sleep, bedtime vs. morning ingestion of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers better reduces the asleep BP mean, with additional benefit, independent of medication terminal half-life, of converting the 24 h BP profile into more normal dipper patterning. The MAPEC (Monitorización Ambulatoria para Predicción de Eventos Cardiovasculares) study, first prospective randomized treatment-time investigation designed to test the worthiness of bedtime chronotherapy with ⩾1 conventional hypertension medications so as to specifically target attenuation of asleep BP, demonstrated, relative to conventional morning therapy, 61% reduction of total CVD events and 67% decrease of major CVD events, that is, CVD death, myocardial infarction, and ischemic and hemorrhagic stroke. The MAPEC study, along with other earlier conducted less refined trials, documents the asleep BP mean is the most significant prognostic marker of CVD morbidity and mortality; moreover, it substantiates attenuation of the asleep BP mean by a bedtime hypertension treatment strategy entailing the entire daily dose of ⩾1 hypertension medications significantly reduces CVD risk in both general and more vulnerable hypertensive patients, that is, those diagnosed with chronic kidney disease, diabetes and resistant hypertension.

Chronotherapy in practice: the perspective of the community pharmacist

BACKGROUND

Optimising the time of drug administration in alignment with circadian rhythms to enhance the clinical effect or minimise/avoid adverse effects is referred to as chronotherapy. Pharmacists have a key role in providing medicine related information, including counselling about the optimal time for medication administration. Where applicable, the principles of chronotherapy should underlie this aspect of medication counselling. Despite significant developments in the science of chronotherapy for specific pharmacological treatments, the perspective of pharmacists about their understanding and application of these principles in practice has not been explored.

OBJECTIVE

To explore community pharmacist's viewpoints about and experience with the application of chronotherapy principles in practice.

SETTING

Community pharmacies within metropolitan Sydney in New South Wales, Australia.

METHODS

Semi-structured, face to face interviews with a convenience sample of community pharmacists were conducted. All interviews were audio-recorded, transcribed verbatim and thematically analyzed using a 'grounded theory' approach, given the novelty of this area. Main outcome measure Community pharmacists' awareness, current practice and future practice support requirements about the principles of chronotherapy.

RESULTS

Twenty-five semi-structured interviews were conducted. Most participants reported encountering cases where clinical decision making about suggesting appropriate times of drug administration to patients was needed. Their approach was mainly pragmatic rather than based on theoretical principles of circadian variation in drug disposition or on current or emerging evidence; thus there was an evidence practice chasm in some cases. However, most participants believed they have an important role to play in counselling patients about optimal administration times and were willing to enact such roles or acquire skills/competence in this area.

CONCLUSION

Community pharmacists contribute to the safe and effective use of medications in providing the patients with information on optimal timing of drug administration during counselling. Further education, practical training and access to information may help pharmacists in translating principles of chronotherapy into the practice.

Ambulatory Blood Pressure Monitoring (ABPM) as the reference standard for diagnosis of hypertension and assessment of vascular risk in adults

New information has become available since the ISC, AAMCC, and SECAC released their first extensive guidedelines to improve the diagnosis and treatment of adult arterial hypertension. A critical assessment of evidence and a comparison of what international guidelines now propose are the basis for the following statements, which update the recommendations first issued in 2013. Office blood pressure (BP) measurements should no longer be considered to be the "gold standard" for the diagnosis of hypertension and assessment of cardiovascular risk. Relying on office BP, even when supplemented with at-home wake-time self-measurements, to identify high-risk individuals, disregarding circadian BP patterning and asleep BP level, leads to potential misclassification of 50% of all evaluated persons. Accordingly, ambulatory BP monitoring is the recommended reference standard for the diagnosis of true hypertension and accurate assessment of cardiovascular risk in all adults ≥18 yrs of age, regardless of whether office BP is normal or elevated. Asleep systolic BP mean is the most significant independent predictor of cardiovascular events. The sleep-time relative SBP decline adds prognostic value to the statistical model that already includes the asleep systolic BP mean and corrected for relevant confounding variables. Accordingly, the asleep systolic BP mean is the recommended protocol to diagnose hypertension, assess cardiovascular risk, and predict cardiovascular event-free interval. In men, and in the absence of compelling clinical conditions, reference thresholds for diagnosing hypertension are 120/70 mmHg for the asleep systolic/diastolic BP means derived from ambulatory BP monitoring. However, in women, in the absence of complicating co-morbidities, the same thresholds are lower by 10/5 mmHg, i.e., 110/65 mmHg for the asleep means. In high-risk patients, including those diagnosed with diabetes or chronic kidney disease, and/or those having experienced past cardiovascular events, the thresholds are even lower by 15/10 mmHg, i.e., 105/60 mmHg. Bedtime treatment with the full daily dose of ≥1 hypertension medications is recommended as a cost-effective means to improve the management of hypertension and reduce hypertension-associated risk. Bedtime treatment entailing the full daily dose of ≥1 conventional hypertension medications must be the therapeutic regimen of choice for the elderly and those with diabetes, resistant and secondary hypertension, chronic kidney disease, obstructive sleep apnea, and medical history of past cardiovascular events, among others, given their documented high prevalence of sleep-time hypertension.

Gentamicin-induced ototoxicity and nephrotoxicity vary with circadian time of treatment and entail separate mechanisms

The aminoglycoside antibiotic gentamicin can cause both ototoxicity and nephrotoxicity, the severity of which varies with circadian time of daily treatment. However, it is not yet resolved if such drug-induced adverse effects are independent or interdependent phenomena. Two groups of 9 female Sprague-Dawley rats (200-250 g), each housed separately and entrained to a 12 h light (06:00-18:00 h) - 12 h dark cycle, received a daily subcutaneous injection of 100 mg/kg gentamicin. One group was treated at the beginning of the activity span, 2 Hours After Lights On (HALO), and the other at the beginning of the rest span, 14 HALO. Global toxicity was gauged by both body weight loss relative to the pre-treatment baseline and number of deaths. Ototoxicity, i.e., hearing loss, was assessed by changes in auditory brainstem response (ABR) for pure tone stimuli of 8, 16, 24, and 32 kHz before and after 2 and 4 weeks of gentamicin treatment. Renal toxicity was evaluated by changes in urinary N-acetyl-β-glucosaminidase (NAG)/creatinine (CR) concentration ratio before and after each week of treatment. In a complementary substudy of separate but comparable 2 and 14 HALO groups of rats, blood samples were obtained before and 30, 60, 120, and 240 min post-subcutaneous injection of 100 mg/kg gentamicin. Number of animal deaths was greater in the 2 (4 deaths) than 14 HALO (1 death) group, mirroring more severe initial (first two weeks of treatment) body weight losses from baseline, being more than 2-fold greater in animals of the 2 than 14 HALO group. Ototoxicity progressively worsened during the treatment; although, the extent of hearing loss varied according to circadian time of treatment across all frequencies (p < 0.05), particularly the 24 and 32 kHz ones (both p < 0.005), both at the 2 and 4 week assessments. At 32 kHz after 4 weeks of gentamicin dosing, the 2 HALO group showed an average 42 dB hearing loss, while the 14 HALO group exhibited only an average 10 dB loss. ABR response latencies were longer for the 2 than 14 HALO rats. The time course of nephrotoxicity differed from that of ototoxicity. The mean urinary NAG/CR ratio peaked after the first week of treatment, averaging 13.64-fold greater than baseline for the 2 HALO-treated animals compared to 7.38-fold greater than baseline for the 14 HALO-treated ones. Ratio values declined thereafter; although, even after the second week of dosing, they remained greater in the 2 than 14 HALO group (averaging 8.15-fold greater and 2.23-fold greater than baseline, respectively). Pharmacokinetic analysis of the blood gentamicin values revealed slower clearance, on average by ∼25% (p < 0.001), in the rats of the 14 than 2 HALO group (x ± S.E.: 3.22 ± 0.49 and 4.53 ± 0.63 mL/min/kg, respectively). The study findings indicate robust difference of the time course in rats of both treatment groups of gentamicin-induced ototoxicity and nephrotoxicity, supporting the hypothesis these organ toxicities are independent of one another, and further suggest the observed treatment-time differences in gentamicin adverse effects may be more dependent on local cell, tissue, or organ circadian (chrono) pharmacodynamic than (chrono) pharmacokinetic mechanisms.

[Hypertension and cardiovascular risk associated with obstructive sleep apnea in adult in Guadeloupe (French West Indies)]

BACKGROUND AND PURPOSE

In Guadeloupe, data on the relationships between arterial hypertension and obstructive sleep apnea are unavailable. The aim of this study was: to assess the frequency of hypertension and non-dipper pattern evaluated by 48-hour ambulatory blood pressure monitoring in an adult population identified obstructive sleep apnea/non-obstructive sleep apnea during overnight polygraphy ; to determine the cardio-metabolic factors associated with obstructive sleep apnea.

DESIGN AND METHOD

A cross-sectional study was realized at Pointe-à-Pitre Hospital. Patients were referred for suspected sleep apnea to sleep specialist and performed a nocturnal polygraphy. Diagnosis was confirmed if the apnea-hypopnea index was ≥ 5. We obtained two groups: sleep apnea/non-sleep apnea. All patients underwent 48-hour ambulatory blood pressure monitoring. The cardio-metabolic factors were identified and assessed (fasten level of hs-CRP and Homa-IR index).

RESULTS

A total of 204 patients were included. Mean age at diagnosis was 54 ± 10 years, 63% were women. OSA was present in 69.6% with a higher frequency in men than in women. Difference was not significant between the two groups for hypertension frequency (84.5% vs 77%; P=0.22), non-dipper pattern (77.5% vs 76%; P=0.79) and hs-CRP. Differences for age, snoring, body max index, mean waist circumference, Homa-IR index, obesity, dyslipidemia, and type 2 diabetes were significant.

CONCLUSIONS

Our data highlight raised frequency of cardiovascular metabolic factors in patients with obstructive sleep apnea and confirm their high cardiovascular risk.

Olmesartan in the treatment of hypertension in elderly patients: a review of the primary evidence

Hypertension, particularly systolic hypertension, is prevalent in the elderly and increases with advancing age, in part because of age-related endothelial dysfunction and increased arterial stiffness. There is strong evidence from randomized clinical trials that supports the use of antihypertensive treatment for effective and sustained blood pressure (BP) control in older patients to reduce the risk of vascular-related morbidity and mortality, particularly cerebrovascular accidents, including stroke. Furthermore, current evidence and guidelines suggest that all major classes of antihypertensive agents are equally effective in controlling BP and preventing cardiovascular events in older patients. Diuretics are commonly used in elderly patients, but recent outcomes data have raised doubt about their long-term benefits. Renin-angiotensin system inhibitors have a better tolerability profile than diuretics. Extensive clinical evidence has demonstrated the excellent efficacy and tolerability profile of olmesartan medoxomil (OM)--an angiotensin II receptor blocker AT1 receptor antagonist--including in elderly patients. Randomized and observational studies have shown that OM provides effective BP control across the 24 h dosing interval in the elderly. It also has a good tolerability profile, a pharmacokinetic profile unaffected by age and a low propensity for drug interactions. An additional factor is that OM once-daily regimens are simple and straightforward, which can be an important factor in maintaining adherence to therapy in elderly patients. This article provides an overview of the main recent clinical evidence supporting the use of OM-based therapy in elderly patients with hypertension.

Relationships of different blood pressure categories to indices of inflammation and platelet activity in sustained hypertensive patients with uncontrolled office blood pressure

Failure to decrease blood pressure (BP) normally during nighttime (non-dipping) in hypertension is associated with higher cardiovascular morbidity and mortality. In addition, non-dipping BP is associated with increased platelet activity and inflammatory response; however, there has been no study to evaluate the relationship of non-dipping BP to indices of platelet activity and inflammation in uncontrolled hypertensive patients. In the present study, hypertensive subjects with uncontrolled office BP were firstly divided into three groups: 84 subjects with white coat effect and 365 subjects with true uncontrolled hypertension. Then, true uncontrolled hypertensive patients were divided into two groups: 158 patients with dipping and 207 patients with non-dipping. Mean platelet volume (MPV), uric acid (UA), γ-glutamyltransferase (GGT), C-reactive protein (CRP), and high-sensitivity CRP (hs-CRP) levels were studied. The general characteristics and risk factors for coronary artery disease (CAD) of the study population were similar among the groups. MPV, UA, GGT, CRP, and hs-CRP levels were significantly higher in non-dipper group than both dipper and white coat effect groups, and were significantly higher in dipper group than in white coat effect group (MPV: 9.1 ± 1.3, 8.7 ± 1.1, and 8. ± 0.9 fL; UA: 6.9 ± 1.2, 5.9 ± 1.4, and 4.1 ± 0.8 mg/dL; GGT: 38.9 ± 11.1, 33.6 ± 14.9, and 25.2 ± 9.2 U/L; CRP: 7.1 ± 2.4, 6.2 ± 1.9, and 3.9 ± 0.8 mg/dL; hs-CRP: 3.8 ± 1.5, 3.3 ± 1.2, and 2.0 ± 0.6, non-dipper, dipper, and white coat effect groups, respectively, all p values <0.01). All study parameters strongly correlated with each other. In conclusion, in hypertensive patients with uncontrolled office BP, presence of non-dipping BP is associated with increased platelet activity and inflammation, which can be one of the underlying plausible mechanisms of non-dipping BP status.

Chronotherapy improves blood pressure control and reduces vascular risk in CKD

In patients with chronic kidney disease (CKD), the prevalence of increased blood pressure during sleep and blunted sleep-time-relative blood pressure decline (a nondipper pattern) is very high and increases substantially with disease severity. Elevated blood pressure during sleep is the major criterion for the diagnoses of hypertension and inadequate therapeutic ambulatory blood pressure control in these patients. Substantial, clinically meaningful ingestion-time-dependent differences in the safety, efficacy, duration of action and/or effects on the 24 h blood pressure pattern of six different classes of hypertension medications and their combinations have been substantiated. For example, bedtime ingestion of angiotensin-converting-enzyme inhibitors and angiotensin-receptor blockers is more effective than morning ingestion in reducing blood pressure during sleep and converting the 24 h blood pressure profile into a dipper pattern. We have identified a progressive reduction in blood pressure during sleep--a novel therapeutic target best achieved by ingestion of one or more hypertension medications at bedtime--as the most significant predictor of decreased cardiovascular risk in patients with and without CKD. Recent findings suggest that in patients with CKD, ambulatory blood pressure monitoring should be used for the diagnosis of hypertension and assessment of cardiovascular disease risk, and that therapeutic strategies given at bedtime rather than on awakening are preferable for the management of hypertension.

Dipper and non-dipper blood pressure 24-hour patterns: circadian rhythm-dependent physiologic and pathophysiologic mechanisms

Neuroendocrine mechanisms are major determinants of the normal 24-h blood pressure (BP) pattern. At the central level, integration of the major driving factors of this temporal variability is mediated by circadian rhythms of monoaminergic systems in conjunction with those of the hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, opioid, renin-angiotensin-aldosterone, plus endothelial systems and specific vasoactive peptides. Humoral secretions are typically episodic, coupled either to sleep and/or the circadian endogenous (suprachiasmatic nucleus) central pacemaker clock, but exhibiting also weekly, monthly, seasonal, and annual periodicities. Sleep induction and arousal are influenced also by many hormones and chemical substances that exhibit 24-h variation, e.g., arginine vasopressin, vasoactive intestinal peptide, melatonin, somatotropin, insulin, steroids, serotonin, corticotropin-releasing factor, adrenocorticotropic hormone, thyrotropin-releasing hormone, endogenous opioids, and prostaglandin E2, all with established effects on the cardiovascular system. As a consequence, physical, mental, and pathologic stimuli that activate or inhibit neuroendocrine effectors of biological rhythmicity may also interfere with, or modify, the temporal BP structure. Moreover, immediate adjustment to exogenous components/environment demands by BP rhythms is modulated by the circadian-time-dependent responsiveness of biological oscillators and their neuroendocrine effectors. This knowledge contributes to a better understanding of the pathophysiology of abnormalities of the 24-h BP pattern and level and their correction through circadian rhythm-based chronotherapeutic strategies.