Characteristics, drug combinations and dosages of primary care patients with uncontrolled ambulatory blood pressure and high medication adherence

Identifying pseudo-resistant hypertension and optimizing diuretic therapy for confirmed resistant cases in primary care

Background

Approximately 10% of individuals with hypertension are expected to have resistant hypertension (RH). Many have pseudo-resistant hypertension (p-RH) due to a variety of factors. To date, the prevalence of p-RH and optimal diuretic therapy in primary care have not been studied.

Methods

A retrospective chart review was conducted, including patients referred to the hypertension clinic at the Centre for Family Medicine (CFFM) Family Health Team in Kitchener, ON, from January 2010 to September 2020. Individuals ≥18 years old referred to clinic by their family physician or other health care provider with 2 consecutive blood pressure (BP) readings of ≥140/90 mmHg despite using ≥3 antihypertensive agents were included.

Results

Fifty-one patients taking ≥3 antihypertensive agents were referred during the study timeframe. Forty-one patients had ≥2 consecutive BP readings of ≥140/90 and were classified as having presumed RH. Of these, 24 patients (59%) had p-RH after BP was measured systematically in the hypertension clinic. Of the 17 with RH, 5 (29%) were prescribed optimal diuretic therapy upon referral. Most common clinic interventions included initiating or adjusting the dose of a diuretic (47%), adding a different antihypertensive agent (27%) or discontinuing an antihypertensive agent due to side effects (24%).

Discussion

To our knowledge, this is the first time that the prevalence of p-RH and optimal diuretic therapy have been studied in primary care. p-RH was common and diuretic therapy was underused in RH.

Conclusion

This study suggests that p-RH is prevalent and diuretic therapy underused in primary care. Systematic BP measurement and optimization of diuretic therapy should be prioritized prior to specialist referral.

Controversies in Hypertension V: Resistant and Refractory Hypertension

Apparent resistant hypertension, defined as uncontrolled office blood pressure despite ≥ 3 antihypertensive medications including a diuretic or use of ≥ 4 medications regardless of blood pressure, occurs in ≤ 15% of treated hypertensives. Apparent refractory hypertension, defined as uncontrolled office pressure despite use of 5 or more medications including a diuretic, occurs in ≤ 10% of resistant cases. Both are associated with increased comorbidity and enhanced cardiovascular risk. To rule out pseudo-resistant or pseudo-refractory hypertension, employ guideline-based methodology for obtaining pressure, maximize the regimen, rule out white-coat effect, and assess adherence. True resistant hypertension is characterized by volume overload and aldosterone excess, refractory by enhanced sympathetic tone. Spironolactone is the preferred agent for resistance, with lower doses. Spironolactone, potassium binders, or both, are preferred if the estimated glomerular filtration rate is below 45. If significant albuminuria, finerenone is indicated. The optimal treatment of refractory hypertension is unclear, but sympathetic inhibition (α-β blockade, centrally acting sympathoinhibitors, or both) seems reasonable. Renal denervation has shown minimal benefit for resistance, but its role in refractory hypertension remains to be defined.

Prescribing patterns of antihypertensive medications: A systematic review of literature between 2010 and 2020

Background

Hypertension has affected over 1.13 billion people worldwide in 2015 and it's one of the most preventable risk-factors for morbidity and mortality. Antihypertensives significantly reduce cardiovascular risks. Several studies on antihypertensives' prescribing patterns were conducted worldwide, and guidelines were developed on hypertension management. However, no systematic reviews were conducted globally to synthesize the evidence from these studies. This review aims to evaluate antihypertensives' prescription patterns, and adherence to international guidelines for hypertension management worldwide.

Methods

Full-text antihypertensives' prescribing patterns evaluation studies were included. Reviews, commentaries, guidelines, and editorials were excluded. Various databases were searched including PubMed, Embase, and others. Studies were limited to English only and to articles published from (01/01/2010) to (20/03/2020). Crowe Critical Appraisal Tool (CCAT) was used for quality assessment.

Results

The most commonly prescribed antihypertensives as monotherapy in adult patients with no comorbidities were ACEIs/ARBs (Angiotensin converting enzyme inhibitors/Angiotensin receptor blockers), followed by CCBs (Calcium channel blockers), and BBs (Beta Blockers). Most commonly prescribed dual combinations were thiazide diuretics+ACEIs/ARBs, BBs + CCBs and CCBs+ACEIs/ARBs. Among diabetic patients, the most common agents were ACEIs/ARBs. Among patients with heart diseases, CCBs were prescribed frequently. While patients with kidney diseases, CCBs and ARBs were most prescribed. Of the 40 studies included in the review, only four studies directly assessed the prescribing patterns of antihypertensives in adherence to clinical practice guidelines. And only two studies confirmed adherence to guidelines. Furthermore, the quality of the majority of studies was moderate (50%), while 25% of articles were reported as either high or low quality.

Conclusion

This review revealed that there are areas for improvement for prescribing practices of antihypertensives in concordance with the latest evidence and with clinical practice guidelines.

Role of home blood pressure monitoring in resistant hypertension

The definition of resistant hypertension (RHT) has been updated to include failure to achieve target blood pressure (BP) despite treatment with ≥3 antihypertensive drugs, including diuretics, renin-angiotensin system blockers, and calcium channel blockers, prescribed at the maximum or maximally tolerated doses, or as success in achieving the target blood pressure but requiring ≥4 drugs. RHT is a major clinical problem, as it is associated with higher mortality and morbidity than non-RHT. Therefore, it is crucial to accurately identify RHT patients to effectively manage their disease. Out-of-clinic BP measurement, including home BP monitoring and ambulatory BP monitoring is gaining prominence for the diagnosis and management of RHT. Home BP monitoring is advantageous as it is feasibly repetitive, inexpensive, widely available, and because of its reproducibility over long periods. In addition, home BP monitoring has crucial advantage of allowing safe titration for the maximum or maximally tolerable dose, and for self-monitoring, thereby improving clinical inertia and nonadherence, and allowing true RHT to be more accurately identified.

Immune Mechanisms of Dietary Salt-Induced Hypertension and Kidney Disease: Harry Goldblatt Award for Early Career Investigators 2020

Salt sensitivity of blood pressure is an independent risk factor for cardiovascular mortality not only in hypertensive but also in normotensive adults. The diagnosis of salt sensitivity of blood pressure is not feasible in the clinic due to lack of a simple diagnostic test, making it difficult to investigate therapeutic strategies. Most research efforts to understand the mechanisms of salt sensitivity of blood pressure have focused on renal regulation of sodium. However, salt retention or plasma volume expansion is not different between salt-sensitive and salt-resistant individuals. In addition, over 70% of extracellular fluid is interstitial and, therefore, not directly controlled by renal salt and water excretion. We discuss in this review how the seminal work by Harry Goldblatt paved the way for our attempts at understanding the mechanisms that underlie immune activation by salt in hypertension. We describe our findings that sodium, entering antigen-presenting cells via an epithelial sodium channel, triggers a PKC (protein kinase C)- and SGK1 (serum/glucocorticoid kinase 1)-stimulated activation of nicotinamide adenine dinucleotide phosphate oxidase, which, in turn, enhances lipid oxidation with generation of highly reactive isolevuglandins. Isolevuglandins adduct to proteins, with the potential to generate degraded peptide neoantigens. Activated antigen-presenting cells increase production of the TH17 polarizing cytokines, IL (interleukin)-6, IL-1β, and IL-23, which leads to differentiation and proliferation of IL-17A producing T cells. Our laboratory and others have shown that this cytokine contributes to hypertension. We also discuss where this sodium activation of antigen-presenting cells may occur in vivo and describe the multiple experiments, with pharmacological antagonists and knockout mice that we used to unravel this sequence of events in rodents. Finally, we describe experiments in mononuclear cells obtained from normotensive or hypertensive volunteers, which confirm that analogous processes of salt-induced immunity take place in humans.

Hypertension: Do Inflammation and Immunity Hold the Key to Solving this Epidemic?

Elevated cardiovascular risk including stroke, heart failure, and heart attack is present even after normalization of blood pressure in patients with hypertension. Underlying immune cell activation is a likely culprit. Although immune cells are important for protection against invading pathogens, their chronic overactivation may lead to tissue damage and high blood pressure. Triggers that may initiate immune activation include viral infections, autoimmunity, and lifestyle factors such as excess dietary salt. These conditions activate the immune system either directly or through their impact on the gut microbiome, which ultimately produces chronic inflammation and hypertension. T cells are central to the immune responses contributing to hypertension. They are activated in part by binding specific antigens that are presented in major histocompatibility complex molecules on professional antigen-presenting cells, and they generate repertoires of rearranged T-cell receptors. Activated T cells infiltrate tissues and produce cytokines including interleukin 17A, which promote renal and vascular dysfunction and end-organ damage leading to hypertension. In this comprehensive review, we highlight environmental, genetic, and microbial associated mechanisms contributing to both innate and adaptive immune cell activation leading to hypertension. Targeting the underlying chronic immune cell activation in hypertension has the potential to mitigate the excess cardiovascular risk associated with this common and deadly disease.

Reserpine Substantially Lowers Blood Pressure in Patients With Refractory Hypertension: A Proof-of-Concept Study

BACKGROUND

Refractory hypertension (RfHTN), a phenotype of antihypertensive treatment failure, is defined as uncontrolled automated office blood pressure (AOBP) ≥130/80 mm Hg and awake ambulatory blood pressure (ABP) ≥130/80 mm Hg on ≥5 antihypertensive medications, including chlorthalidone and a mineralocorticoid receptor antagonist. Previous studies suggest that RfHTN is attributable to heightened sympathetic tone. The current study tested whether reserpine, a potent sympatholytic agent, lowers blood pressure (BP) in patients with RfHTN.

METHODS

Twenty-one out of 45 consecutive patients with suspected RfHTN were determined to be fully adherent with their antihypertensive regimen. Seven patients agreed to participate in the current clinical trial with reserpine and 6 patients completed the study. Other sympatholytic medications, such as clonidine or guanfacine, were tapered and discontinued before starting reserpine. Reserpine 0.1 mg daily was administered in an open-label fashion for 4 weeks. All patients were evaluated by AOBP and 24-hour ABP at baseline and after 4 weeks of treatment.

RESULTS

Reserpine lowered mean systolic and diastolic AOBP by 29.3 ± 22.2 and 22.0 ± 15.8 mm Hg, respectively. Mean 24-hour systolic and diastolic ABPs were reduced by 21.8 ± 13.4 and 15.3 ± 9.6 mm Hg, mean awake systolic and diastolic ABPs by 23.8 ± 11.8 and 17.8 ± 9.2 mm Hg, and mean asleep systolic and diastolic ABPs by 21.5 ± 11.4 and 13.7 ± 6.4 mm Hg, respectively.

CONCLUSIONS

Reserpine, a potent sympatholytic agent, lowers BP in patients whose BP remained uncontrolled on maximal antihypertensive therapy, lending support to the hypothesis that excess sympathetic output contributes importantly to the development of RfHTN.

Antihypertensive Medication Adherence and Confirmation of True Refractory Hypertension

Refractory hypertension (RfHTN) is a phenotype of antihypertensive treatment failure defined as uncontrolled BP despite the use of effective doses of ≥5 antihypertensive medications including a long-acting thiazide-like diuretic (chlorthalidone) and a mineralocorticoid receptor antagonist. The degree of medication nonadherence is unknown among patients with RfHTN. In this prospective evaluation, 54 patients with apparent RfHTN were recruited from the University of Alabama at Birmingham Hypertension Clinic after having uncontrolled BP at 3 or more clinic visits. All patients' BP was evaluated by automated office BP and 24-hour ambulatory BP monitoring (n=49). Antihypertensive medication adherence was determined by measuring 24-hour urine specimens for antihypertensive medications and their metabolites by high-performance liquid chromatography-tandem mass spectrometry (n=45). Of the 45 patients who completed 24-hour ambulatory BP monitoring, 40 (88.9%) had confirmed RfHTN based on an elevated automated office BP (≥130/80 mm Hg), mean 24-hour ABP (≥125/75 mm Hg), and mean awake (day-time) ABP (≥130/80 mm Hg). Out of the 40 fully evaluated patients with RfHTN, 16 (40.0%) were fully adherent with all prescribed medications. Eighteen (45.0%) patients were partially adherent and 6 (15.0%) had none of the prescribed agents detected in their urine. Of 18 patients who were partially adherent, 5 (12.5%) were adherent with at least 5 medications, including chlorthalidone and the mineralocorticoid receptor antagonist, consistent with true RfHTN. Of patients identified as having apparent RfHTN, 52.5% were adherent with at least 5 antihypertensive medications, including chlorthalidone and a mineralocorticoid receptor antagonist, confirming true RfTHN. These findings validate RfHTN as a rare, but true phenotype of antihypertensive treatment failure.

Resistant Hypertension: Novel Insights

Hypertension is the most common chronic disease and the leading risk factor for disability and premature deaths in the world, accounting for more than 9 million deaths annually. Resistant hypertension is a particularly severe form of hypertension. It was described 50 years ago and since then has been a very active field of research. This review aims at summarizing the most recent findings on resistant hypertension. The recent concepts of apparent- and true-resistant hypertension have stimulated a more precise definition of resistant hypertension taking into account not only the accuracy of blood pressure measurement and pharmacological class of prescribed drugs but also patient adherence to drugs and life-style recommendations. Recent epidemiological studies have reported a 10% prevalence of resistant hypertension among hypertensive subjects and demonstrated the high cardiovascular risk of these patients. In addition, these studies identified subgroups of patients with even higher morbidity and mortality risk, probably requiring a more aggressive medical management. In the meantime, guidelines provided more standardized clinical work-up to identify potentially reversible causes for resistant hypertension such as secondary hypertension. The debate is however still ongoing on which would be the optimal method(s) to screen for non-adherence to hypertension therapy, recognized as the major cause for (pseudo)-resistance to treatment. Recent randomized clinical trials have demonstrated the strong benefit of anti-aldosterone drugs (mostly spironolocatone) as fourth-line therapies in resistant hypertension whereas clinical trials with device-based therapies displayed contrasting results. New trials with improved devices and more carefully selected patients with resistant hypertension are ongoing.

The prevalence and predictors of resistant hypertension in high-risk overweight and obese patients: A cross-sectional study based on the 2017 ACC/AHA guidelines

Obesity is significantly associated with uncontrolled blood pressure and resistant hypertension (RH). There are limited studies on the prevalence and determinants of RH in patients with higher body mass index (BMI) values. Since the hypertension guidelines changed in 2017, the prevalence of RH has become unknown and now is subject to be estimated by further studies. We conducted a cross-sectional study in an urban Federally Qualified Health Center in New York City aiming to estimate the prevalence of RH in high-risk overweight and obese patients based on the new hypertension definition, BP threshold ≥130/80 mm Hg, and also to describe the associated comorbid conditions in these patients. We identified 761 eligible high-risk overweight and obese subjects with hypertension between October 2017 and October 2018. Apparent treatment-RH was found in 13.6% among the entire study population. This represented 15.4% of those treated with BP-lowering agents. True RH confirmed with out-of-office elevated BP was found in 6.7% of the study population and 7.4% among patients treated with BP-lowering agents. Prevalence was higher with higher BMI values. Those with true RH were more likely to be black, to have diabetes mellitus requiring insulin, chronic kidney disease stage 3 or above and diastolic heart failure. In conclusion, obesity is significantly associated with RH and other significant metabolic comorbid conditions.

Masked Uncontrolled Hypertension Is Not Attributable to Medication Nonadherence

Masked uncontrolled hypertension (MUCH) in treated hypertensive patients is defined as controlled automated office blood pressure (BP; <135/85 mm Hg) in-clinic but uncontrolled out-of-clinic BP by ambulatory BP monitoring (awake [daytime] readings ≥135/85 mm Hg or 24-hour readings ≥130/80 mm Hg). To determine whether MUCH is attributable to antihypertensive medication nonadherence. One hundred eighty-four enrolled patients were confirmed to have controlled office BP; of these, 167 patients were with adequate 24-hour ambulatory BP recordings. Of 167 patients, 86 were controlled by in-clinic BP assessment but had uncontrolled ambulatory awake BP, indicative of MUCH. The remaining 81 had controlled in-clinic and ambulatory awake BP, consistent with true controlled hypertension. After exclusion of 9 patients with missing 24-hour urine collections, antihypertensive medication adherence was determined based on the detection of urinary drugs or drug metabolites by high-performance liquid chromatography-tandem mass spectrometry. Of the 81 patients with MUCH, 69 (85.2%) were fully adherent and 12 (14.8%) were partially adherent (fewer medications detected than prescribed). Of the 77 patients with true controlled hypertension, 69 (89.6%) were fully adherent with prescribed antihypertensive medications and 8 (10.4%) were partially adherent. None of the patients in either group were fully nonadherent. There was no statistically significant difference in complete or partial adherence between the MUCH and true controlled groups (P=0.403). Measurement of urinary drug and drug metabolite levels demonstrates a similarly high level of antihypertensive medication adherence in both MUCH and truly controlled hypertensive patients. These findings indicate that MUCH is not attributable to antihypertensive medication nonadherence.

Resistant Hypertension: Detection, Evaluation, and Management: A Scientific Statement From the American Heart Association

Resistant hypertension (RH) is defined as above-goal elevated blood pressure (BP) in a patient despite the concurrent use of 3 antihypertensive drug classes, commonly including a long-acting calcium channel blocker, a blocker of the renin-angiotensin system (angiotensin-converting enzyme inhibitor or angiotensin receptor blocker), and a diuretic. The antihypertensive drugs should be administered at maximum or maximally tolerated daily doses. RH also includes patients whose BP achieves target values on ≥4 antihypertensive medications. The diagnosis of RH requires assurance of antihypertensive medication adherence and exclusion of the "white-coat effect" (office BP above goal but out-of-office BP at or below target). The importance of RH is underscored by the associated risk of adverse outcomes compared with non-RH. This article is an updated American Heart Association scientific statement on the detection, evaluation, and management of RH. Once antihypertensive medication adherence is confirmed and out-of-office BP recordings exclude a white-coat effect, evaluation includes identification of contributing lifestyle issues, detection of drugs interfering with antihypertensive medication effectiveness, screening for secondary hypertension, and assessment of target organ damage. Management of RH includes maximization of lifestyle interventions, use of long-acting thiazide-like diuretics (chlorthalidone or indapamide), addition of a mineralocorticoid receptor antagonist (spironolactone or eplerenone), and, if BP remains elevated, stepwise addition of antihypertensive drugs with complementary mechanisms of action to lower BP. If BP remains uncontrolled, referral to a hypertension specialist is advised.

Renal Innervation in Resistant Hypertension: A Review of Pathophysiology and Renal Denervation as Potential Treatment

Background

Advances in treatment and increased awareness have improved the prognosis for many patients with hypertension (HTN). Resistant hypertension (RH) refers to a subset of hypertensive individuals who fail to achieve a desired blood pressure (BP) despite concurrent use of 3 different classes antihypertensive agents, one being a diuretic, and proper lifestyle changes. The prevalence and prognosis of RH are unclear owing to its heterogeneous etiologies, risk factors, and secondary comorbidities. Previous research has provided evidence that increased renal sympathetic nerve activity (RSNA) within the renal artery contributes to RH development. Renal denervation (RDN) is a procedure that attempts to ameliorate the effects of heightened RSNA via ablation renal sympathetic fibers. BP reductions associated with RDN may be attributed to decreased norepinephrine spillover, restoration of natriuresis, increasing renal blood flow, and lowering plasma renin activity. Early clinical trials perpetuated positive results, and enthusiasm grew exponentially. However, recent clinical trials have called into question RDN's efficacy. Numerous limitations must be addressed to discern the true effectiveness of RDN as a therapeutic option for RH.

Objective

We aimed to review the current understanding of RH, the anatomy of renal arteries, physiology of RH on renal arteries, anatomical pathways of the sympathetic involved in RH, RDN as a treatment option, and all relevant clinical trials treating RH with RDN.

Methods

We piloted a MEDLINE^® database search of literature extending from 1980 to 2017, with emphasis on the previous five years, combining keywords such as “resistant hypertension” and 
“renal denervation.”

Conclusion

A plethora of information is available regarding heightened RSNA leading to RH. RDN as a possible treatment option has shown a range of results. Reconciling RDN's true efficacy requires future trials to increased sites of nerve ablation, standardized protocol, increased anatomical understanding per individual basis, stricter guidelines regarding study design, increased operator experience, and integrating the use of a multielectrode catheter.

Resistant Hypertension: Diagnosis and Management

Resistant hypertension is defined as high blood pressure requiring 3 or more medications for adequate control or controlled blood pressure requiring 4 or more medications. Considering the growing prevalence of hypertension and the strong link with cardiovascular disease, it is vital to understand the causes and treatment of resistant hypertension. This review article starts with an overview of the prevalence and little-known pathophysiology of resistant hypertension. Afterward, we discuss the evaluation and management of suspected secondary resistant hypertension in 2 broad categories: pseudoresistant hypertension and true resistant hypertension. Strategies for the identification and management of pseudoresistant hypertension are addressed. In addition, causes of true resistant hypertension, such as obstructive sleep apnea, primary aldosteronism, and renal artery stenosis, are examined along with their respective treatments. Finally, treatment of resistant hypertension is reviewed including pharmacologic treatments and novel procedural interventions for resistant hypertension. Overall, the review hopes to provide practitioners with a cohesive approach for the diagnosis and treatment of resistant hypertension.

Medication adherence and treatment-resistant hypertension: a review

Nonadherence is a common reason for treatment failure and treatment resistance. No matter how it is defined, it is a major issue in the management of chronic illnesses. There are numerous methods to assess adherence, each with its own strengths and weaknesses; however, no single method is considered the best. Nonadherence is common in patients with hypertension, and it is present in a large proportion of patients with uncontrolled blood pressure taking three or more antihypertensive agents. Availability of procedure-based treatment options for these patients has shed further light on this important issue with development of new methods to assess adherence. There is, however, no consensus on the management of nonadherence, which reflects the complex interplay of factors responsible for it.

Medication adherence among patients with apparent treatment-resistant hypertension: systematic review and meta-analysis

OBJECTIVES

Medication nonadherence is a known behavioural contributor to poor blood pressure (BP) control that puts patients with hypertension at elevated cardiovascular risk. Studies of medication adherence for apparent treatment-resistant hypertension (aTRH) vary significantly with respect to design, methods, and setting, and, as a result, have produced highly variable figures describing the prevalence of nonadherence. This review aimed to describe the prevalence and potential moderators of medication nonadherence estimates for aTRH.

METHODS

Systematic review and random effects meta-analysis.

RESULTS

From an initial discovery of 921 studies, we identified 24 studies that measured medication adherence for patients with uncontrolled BP despite being prescribed three or more antihypertensive medications of different classes. By using a random effects model, the pooled prevalence of nonadherence was 31.2% (95% confidence interval = 20.2-44.7, I = 99.50) with nonadherence rates ranging from 3.3 to 86.1%. The strongest contributor to variance in nonadherence rates was the method of adherence assessment used. Studies that relied on self-report measures of adherence and/or pharmacy data reported lower levels of nonadherence than studies using more objective methods, such as liquid chromatography-mass spectrometry in single time-point bioassays or directly observed therapy.

CONCLUSION

Findings indicate that medication nonadherence is a significant problem among aTRH patients. Identifying the most accurate and clinically feasible adherence assessment methods is necessary to reduce BP and cardiovascular morbidity, facilitate early behavioural intervention, prevent unnecessary diagnostic testing, and limit sometimes unnecessary and expensive BP lowering procedures.

REGISTRATION NUMBER

CRD42016028121.

Refractory versus resistant hypertension: Novel distinctive phenotypes

Resistant hypertension (RHTN) is relatively common with an estimated prevalence of 10-20% of treated hypertensive patients. It is defined as blood pressure (BP) >140/90 mmHg treated with ≥3 antihypertensive medications, including a diuretic, if tolerated. Refractory hypertension is a novel phenotype of severe antihypertensive treatment failure. The proposed definition for refractory hypertension, i.e. BP >140/90 mmHg with use of ≥5 different antihypertensive medications, including a diuretic and a mineralocorticoid receptor antagonist (MRA) has been applied inconsistently. In comparison to RHTN, refractory hypertension seems to be less prevalent than RHTN. This review focuses on current knowledge about this novel phenotype compared with RHTN including definition, prevalence, mechanisms, characteristics and comorbidities, including cardiovascular risk. In patients with RHTN excess fluid retention is thought to be a common mechanism for the development of RHTN. Recently, evidence has emerged suggesting that refractory hypertension may be more of neurogenic etiology due to increased sympathetic activity as opposed to excess fluid retention. Treatment recommendations for RHTN are generally based on use and intensification of diuretic therapy, especially with the combination of a long-acting thiazide-like diuretic and an MRA. Based on findings from available studies, such an approach does not seem to be a successful strategy to control BP in patients with refractory hypertension and effective sympathetic inhibition in such patients, either with medications and/or device based approaches may be needed.

White-Coat Effect Is Uncommon in Patients With Refractory Hypertension

Refractory hypertension is a recently described phenotype of antihypertensive treatment failure defined as uncontrolled blood pressure (BP) despite the use of ≥5 different antihypertensive agents, including chlorthalidone and spironolactone. Recent studies indicate that refractory hypertension is uncommon, with a prevalence of ≈5% to 10% of patients referred to a hypertension specialty clinic for uncontrolled hypertension. The prevalence of white-coat effect, that is, uncontrolled automated office BP ≥135/85 mm Hg and controlled out-of-office BP <135/85 mm Hg, by awake ambulatory BP monitor in hypertensive patients overall is ≈30% to 40%. The prevalence of white-coat effect among patients with refractory hypertension has not been previously reported. In this prospective evaluation, consecutive patients referred to the University of Alabama at Birmingham Hypertension Clinic for uncontrolled hypertension were enrolled. Refractory hypertension was defined as uncontrolled automated office BP ≥135/85 mm Hg with the use of ≥5 antihypertensive agents, including chlorthalidone and spironolactone. Automated office BP measurements were based on 6 serial readings, done automatically with the use of a BpTRU device unobserved in the clinic. Out-of-office BP measurements were done by 24-hour ambulatory BP monitor. Thirty-four patients were diagnosed with refractory hypertension, of whom 31 had adequate ambulatory BP monitor readings. White-coat effect was present in only 2 patients, or 6.5% of the 31 patients with refractory hypertension, suggesting that white-coat effect is largely absent in patients with refractory hypertension. These findings suggest that white-coat effect is not a common cause of apparent lack of BP control in patients failing maximal antihypertensive treatment.

Low Blood Pressure Is Associated With Greater Risk for Cardiovascular Events in Treated Adults With and Without Apparent Treatment-Resistant Hypertension

Apparent treatment-resistant hypertension (aTRH) may confound the reported relationship between low blood pressure (BP) and increased cardiovascular disease (CVD) in treated hypertensive patients. Incident CVD was assessed in treated hypertensive patients with and without aTRH (BP ≥140 and/or ≥90 mm Hg on ≥3 medications or <140/<90 mm Hg on ≥4 BP medications) at three BP levels: 1: <120 and/or <70 mm Hg and <140/<90 mm Hg; 2: 120-139/70-89 mm Hg; and 3: ≥140 and/or ≥90 mm Hg. Electronic health data were matched to emergency and hospital claims for incident CVD in 118 356 treated hypertensive patients. In adults with and without aTRH, respectively, CVD was greater in level 1 versus level 2 (multivariable hazard ratio, 1.88 [95% confidence interval [CI], 1.70-2.07]; 1.71 [95% CI, 1.59-1.84]), intermediate in level 1 versus level 3 (hazard ratio, 1.32 [95% CI, 1.21-1.44]; 0.99, [95% CI, 0.92-1.07]), and lowest in level 2 versus level 3 (hazard ratio, 0.70 [95% CI, 0.65-0.76]; 0.58, [95% CI, 0.54-0.62]). Low treated BP was associated with more CVD than less stringent BP control irrespective of aTRH.

Prevalence of pseudoresistant hypertension due to inaccurate blood pressure measurement

The prevalence of pseudoresistant hypertension (HTN) due to inaccurate BP measurement remains unknown. Triage BP measurements and measurements obtained at the same clinic visit by trained physicians were compared in consecutive adult patients referred for uncontrolled resistant HTN (RHTN). Triage BP measurements were taken by the clinic staff during normal intake procedures. BP measurements were obtained by trained physicians using the BpTRU (VSM Med Tech Ltd. Coquitlam, Canada) device. The prevalence of uncontrolled RHTN and differences in BP measurements were compared. Of 130 patients with uncontrolled RHTN, 33.1% (n = 43) were falsely identified as having uncontrolled RHTN based on triage BP measurements. The median (inter-quartile range) of differences in systolic BP between pseudoresistant and true resistant groups were 23 (17-33) mm Hg and 13 (6-21) mm Hg, respectively (P = .0001). The median (inter-quartile range) of differences in diastolic BP between the two groups were 12 (7-18) mm Hg and 8 (4-11) mm Hg, respectively (P = .001). Triage BP technique overestimated the prevalence of uncontrolled RHTN in approximately 33% of the patients emphasizing the importance of obtaining accurate BP measurements.

Medication adherence and resistant hypertension

Non-adherence has been a major concern in the treatment of hypertension and is particularly important in understanding and intervening in patients who appear to have resistant hypertension. Relatively few studies have examined the role of non-adherence in resistant hypertension. This review will address issues related to measurement of adherence, adherence interventions and rates of non-adherence in general hypertensive populations and in patients classified as having resistant hypertension.

Detection, evaluation, and treatment of severe and resistant hypertension: proceedings from an American Society of Hypertension Interactive forum held in Bethesda, MD, U.S.A., October 10th 2013

The epidemiology, evaluation, and management of severe and resistant hypertension in the United States (US) are evolving. The American Society of Hypertension held a multi-disciplinary forum in October 2013 to review the available evidence related to the management of resistant hypertension with both drug and device therapies. There is strong evidence that resistant hypertension is an important clinical problem in the US and many other regions of the world. Complex drug therapy is effective in most of the patients with severe and resistant hypertension, but there are certain individuals who may be refractory to multiple-drug regimens or have adverse effects that make adherence to the regimen difficult. When secondary forms of hypertension and pseudo-resistance, such as medication nonadherence, or white-coat hypertension based on marked differences between clinic and 24-hour ambulatory blood pressure monitoring, have been excluded, the impact of device therapy is under evaluation through clinical trials in the US and from clinical practice registries in Europe and Australia. Clinical trial data have been obtained primarily in patients whose resistant hypertension is defined as systolic clinic blood pressures of ≥160 mm Hg (or ≥ 150 mm Hg in type 2 diabetes) despite pharmacologic treatment with at least three antihypertensive drugs (one of which is a thiazide or loop diuretic). Baroreceptor stimulation therapy has shown modest benefit in a moderately sized sham-controlled study in drug-resistant hypertension. Patients selected for renal denervation have typically been restricted to those with preserved kidney function (estimated glomerular filtration rate ≥ 45 mL/min/1.73 m2). The first sham-controlled safety and efficacy trial for renal denervation (SYMPLICITY HTN-3) did not show benefit in this population when used in addition to an average of five antihypertensive medications. Analyses of controlled clinical trial data from future trials with novel designs will be of critical importance to determine the effectiveness of device therapy for patients with severe and resistant hypertension and will allow for proper determination of patient selection and whether it will be acceptable for clinical practice. At present, the focus on the management of severe and resistant hypertension will be through careful evaluation for pseudo-resistance and secondary forms of hypertension, appropriate use of combination pharmacologic therapy, and greater utility of specialists in hypertension.

Role of aldosterone blockade in resistant hypertension

Apparent treatment-resistant hypertension (aTRH), defined as uncontrolled blood pressure using 3 or more antihypertensive medications or controlled using 4 or more antihypertensive medications, affects approximately 30% of uncontrolled and 12% of controlled blood pressure (BP) patients. aTRH is used when pseudoresistance cannot be excluded (eg, BP measurement artifacts, mainly office resistance, suboptimal adherence, suboptimal treatment regimens, and true TRH). True TRH comprises approximately 30% to 50% of TRH. Patients with TRH have a high prevalence of obesity, insulin resistance, sleep apnea, and volume expansion. Aldosterone, a mineralocorticoid, is an important contributor to TRH, with primary aldosteronism present in approximately 20% of patients. Spironolactone, a mineralocorticoid-receptor antagonist, as a fourth-line agent, decreases BP 20 to 25/10 to 12 mm Hg in TRH patients with and without primary aldosteronism. The BP response to spironolactone is roughly double that of other classes of antihypertensive medications in TRH. Although approximately 70% of patients with uncontrolled TRH have estimated glomerular filtration rate of 50 or greater and a serum potassium level of 4.5 or less, which are associated with a low risk for hyperkalemia, only a small percentage receive a mineralocorticoid-receptor antagonist. This review examines the clinical epidemiology and pharmacotherapy of controlled and uncontrolled hypertension with an emphasis on aTRH, the role of aldosterone in blood pressure regulation, and the potential benefits of mineralocorticoid-receptor antagonist in uncontrolled TRH.