Potential cost-effectiveness of therapeutic drug monitoring in patients with resistant hypertension

Cost-Effectiveness of Routine Monitoring of Long-Term Conditions in Primary Care: Informing Decision Modelling with a Systematic Review in Hypertension, Type 2 Diabetes and Chronic Kidney Disease

BACKGROUND

Long-term conditions (LTCs) are major public health problems with a considerable health-related and economic burden. Modelling is key in assessing costs and benefits of different disease management strategies, including routine monitoring, in the conditions of hypertension, type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) in primary care.

OBJECTIVE

This review aimed to identify published model-based cost-effectiveness studies of routine laboratory testing strategies in these LTCs to inform a model evaluating the cost effectiveness of testing strategies in the UK.

METHODS

We searched the Medline and Embase databases from inception to July 2023; the National Institute for Health and Care Institute (NICE) website was also searched. Studies were included if they were model-based economic evaluations, evaluated testing strategies, assessed regular testing, and considered adults aged >16 years. Studies identified were summarised by testing strategies, model type, structure, inputs, assessment of uncertainty, and conclusions drawn.

RESULTS

Five studies were included in the review, i.e. Markov (n = 3) and microsimulation (n = 2) models. Models were applied within T2DM (n = 2), hypertension (n = 1), T2DM/hypertension (n = 1) and CKD (n = 1). Comorbidity between all three LTCs was modelled to varying extents. All studies used a lifetime horizon, except for a 10-year horizon T2DM model, and all used quality-adjusted life-years as the effectiveness outcome, except a TD2M model that used glycaemic control. No studies explicitly provided a rationale for their selected modelling approach. UK models were available for diabetes and CKD, but these compared only a limited set of routine monitoring tests and frequencies.

CONCLUSIONS

There were few studies comparing routine testing strategies in the UK, indicating a need to develop a novel model in all three LTCs. Justification for the modelling technique of the identified studies was lacking. Markov and microsimulation models, with and without comorbidities, were used; however, the findings of this review can provide data sources and inform modelling approaches for evaluating the cost effectiveness of testing strategies in all three LTCs.

The effect of combining therapeutic drug monitoring of antihypertensive drugs with personalised feedback on adherence and resistant hypertension: the (RHYME-RCT) trial protocol of a multi-centre randomised controlled trial

BACKGROUND

Adherence to antihypertensive drugs (AHDs) is important for adequate blood pressure control. Not taking these drugs as prescribed is one of the main underlying causes for resistant hypertension (RH), which in turn leads to an increased risk of cardiovascular events, stroke and kidney damage. Therefore, correct identification of patients that are non-adherent to AHDs is crucial to improve clinical outcome. For this goal, therapeutic drug monitoring is the most reliable method. The primary objective of this trial is to investigate whether monitoring of drug concentrations with a dried blood spot (DBS) sampling method combined with personalised feedback leads to a decrease in prevalence of RH after 12 months due to an increase in adherence. Secondary objectives include the difference over time in the number of required AHDs as well as the defined daily dose (DDD). Lastly, the cost-utility of SoC versus the intervention in RH is determined.

METHODS

This is a multi-centre single-blinded randomised controlled trial (RHYME-RCT). First, at an eligibility visit, DBS sampling, to monitor drug concentrations in blood, and a 24-h ambulatory blood pressure measurement (24-h ABPM) are performed simultaneously. Patients with a daytime systolic blood pressure (SBP) > 135 and/or diastolic blood pressure (DBP) > 85 mmHg are randomised to SoC or intervention + SoC. The intervention is performed by the treating physician and includes information on drug concentrations and a comprehensive personalised feedback conversation with the use of a communication tool. The follow-up period is one year with visits at 3, 6 and 12 months randomisation and includes 24-h ABPM and DBS sampling.

DISCUSSION

This will be the first trial that focusses specifically on patients with RH without taking into account suspicion of non-adherence and it combines monitoring of AHD concentrations to identify non-adherence to AHDs with a comprehensive feedback to improve non-adherence. Furthermore, if this trial shows positive outcomes for the intervention it can be directly implemented in clinical practice, which would be a great improvement in the treatment of RH.

TRIAL REGISTRATION

RHYME-RCT is registered in the Dutch Trial Register on 27/12/2017 (NTR6914) and can be found in the International Clinical Trials Registry Platform.

[Therapeutic drug monitoring to optimize psychopharmacotherapy in children and adolescents - Update and guidelines for practice]

Therapeutic drug monitoring to optimize psychopharmacotherapy in children and adolescents - Update and guidelines for practice Abstract. Despite the improved evidence base, many uncertainties remain in child and adolescent psychiatric pharmacotherapy about the efficacy and tolerability of drugs, which are often prescribed off-label or in combination therapy in this age group. Because medium- to long-term use is unavoidable in many cases, clinicians should minimize adverse drug reactions as far as possible and tailor an effective dosage to the individual characteristics of the patient. Not only are children and adolescents particularly vulnerable to certain adverse drug effects, they are also exposed to iatrogenic risks from dosing or application errors, which can lead to under- or overdosing with correspondingly negative effects on the success of the therapy. In addition to determining a strict indication, it is therefore essential to establish precise dosage and systematic monitoring of the safety of the psychopharmacotherapy. This article introduces therapeutic drug monitoring as a useful clinical tool and describes how its correct application in practice can improve the efficacy as well as the safety and tolerability of psychotropic therapy in children and adolescents for the immediate benefit of patients. Keywords: Psychopharmacotherapy, adverse drug reactions, pharmacovigilance, therapeutic drug monitoring, quality assurance.

Serum Inhaled Corticosteroid Detection for Monitoring Adherence in Severe Asthma

BACKGROUND

Daily inhaled corticosteroids (ICSs) are fundamental to asthma management, but adherence is low.

OBJECTIVES

To investigate (1) whether LC-MS/MS could be used to detect ICSs in serum and (2) whether serum levels related to markers of disease severity.

METHODS

We collected blood samples over an 8-hour period from patients with severe asthma prescribed at least 1000 μg daily of beclomethasone dipropionate equivalent. Following baseline sampling, patients were observed taking their usual morning dose. Subsequent blood samples were obtained 1, 2, 4, and 8 hours postinhalation and analyzed by LC-MS/MS. Correlations between serum ICS levels and severity markers were investigated.

RESULTS

A total of 60 patients were recruited (41 females; 39 prescribed maintenance prednisolone; mean age, 49 ± 12 years; FEV₁, 63 ± 20 %predicted). Eight hours postinhalation, all patients using budesonide (n = 10) and beclomethasone dipropionate (15), and all but 1 using fluticasone propionate (28), had detectable serum drug levels. Fluticasone furorate was detected in 2 patients (of 4), ciclesonide in none (of 7). Low adherence by repeat prescription records (<80%) was identified in 43%. Blood ICS levels correlated negatively with exacerbation rate, and (for fluticasone propionate only) positively with FEV₁ %predicted.

CONCLUSIONS

Commonly used ICSs can be reliably detected in the blood at least 8 hours after dosing, and could therefore be used as a measure of adherence in severe asthma. Higher exacerbation rates and poorer lung function (for fluticasone propionate) were associated with lower blood levels.

Resistant hypertension: new insights and therapeutic perspectives

Resistant hypertension (RH) is a concept that currently goes beyond the classical definition of blood pressure ≥140/90 mmHg in subjects receiving three or more drugs of different classes at maximally tolerated doses. Here, we review the clinical relevance of RH and the different types of RH-associated phenotypes, namely refractory hypertension, controlled resistant hypertension, and masked uncontrolled hypertension. We also discuss current drug strategies and future treatments for these high-risk phenotypes.

Assessment of patient and provider attitudes towards therapeutic drug monitoring to improve medication adherence in low-income patients with hypertension: a qualitative study

OBJECTIVES

Previous studies have implicated therapeutic drug monitoring (TDM), by measuring serum or urine drug levels, as a highly reliable technique for detecting medication non-adherence but the attitudes of patients and physicians toward TDM have not been evaluated previously. Accordingly, we solicited input from patients with uncontrolled hypertension and their physicians about their views on TDM.

DESIGN

Prospective analysis of responses to a set of questions during semistructured interviews.

SETTING

Outpatient clinics in an integrated health system which provides care for a low-income, uninsured population.

PARTICIPANTS

Patients with uncontrolled hypertension with either systolic blood pressure of at least 130 mm Hg or diastolic blood pressure of at least 80 mm Hg despite antihypertensive drugs and providers in the general cardiology and internal medicine clinics.

PRIMARY AND SECONDARY OUTCOME MEASURES

Attitudes towards TDM and the potential impact on physician-patient relationship.

RESULTS

We interviewed 11 patients and 10 providers and discussed the findings with 13 community advisory panel (CAP) members. Of the patients interviewed, 91% (10 of 11) and all 10 providers thought TDM was a good idea and should be used regularly to better understand the reasons for poorly controlled hypertension. However, 63% (7 of 11) of patients and 20% of providers expressed reservations that TDM could negatively impact the physician-patient relationship. Despite some concerns, the majority of patients, providers and CAP members believed that if test results are communicated without blaming patients, the potential benefits of TDM in identifying suboptimal adherence and eliciting barriers to adherence outweighed the risks.

CONCLUSION

The idea of TDM is well accepted by patients and their providers. TDM information if delivered in a non-judgmental manner, to encourage an honest conversation between patients and physicians, has the potential to reduce patient-physician communication obstacles and to identify barriers to adherence which, when overcome, can improve health outcomes.

Cost effectiveness of therapeutic drug monitoring for imatinib administration in chronic myeloid leukemia

BACKGROUND

Imatinib mesylate (IM) is a first-line treatment option for patients with chronic myeloid leukemia (CML). Patients who fail or are intolerant to IM therapy are treated with more expensive second and third-generation tyrosine kinase inhibitors. Patients show wide variation in trough concentrations in response to standard dosing. Thus, many patients receive subtherapeutic or supratherapeutic doses. Therapeutic drug monitoring (TDM) may improve dose management that, in turn, may reduce costs and improve outcomes. However, TDM also adds to the cost of patient care. The objective of this study was to determine the cost-effectiveness of TDM for generic IM therapy.

METHODS

We developed a microsimulation model for the trough plasma concentration of IM which is related to a cytogenetic or molecular response. We compared two cohorts: one with TDM and one without TDM (NTDM). The lifetime incremental cost-effectiveness ratio (ICER) was calculated using quality-adjusted life years (QALYs) as the effectiveness measure. One-way and probabilistic sensitivity analyses were performed.

RESULTS

The lifetime cost and QALY of treatment with TDM were $2,137K [95% Ci: 2,079K; 2,174K] and 12.37 [95% CI: 12.07; 12.55], respectively. The cost and QALY of NTDM were $2,132K [95% CI: 2,091K; 2,197K] and 12.23 [95% CI: 11.96; 12.50], respectively. The incremental cost and QALY for TDM relative to NTDM was $4,417 [95% CI: -52,582; 32,097]) and 0.15 [95% CI: -0.13; 0.28]. The ICER for TDM relative to NTDM was $30,450/QALY. Probabilistic sensitivity analysis showed that TDM was cost-effective relative to NTDM in 90% of the tested scenarios at a willingness-to-pay threshold of $100,000/QALY.

CONCLUSIONS

Although the impact of TDM is modest, the cost-effectiveness over a lifetime horizon (societal perspective, ($30,450/QALY) falls within the acceptable range (< $100k/QALY).

Resistant hypertension-defining the scope of the problem

The updated scientific statement by the American Heart Association has defined resistant hypertension (HTN;RH) as uncontrolled blood pressure (BP) ≥ 130/80 mmHg, despite concurrent use of 3 anti-HTN drug classes comprising a calcium channel blocker, a blocker of renin-angiotensin system, and a thiazide diuretic, preferably chlorthalidone. Using the updated BP criteria, the prevalence of RH in the United States is found to be modestly increased by approximately 3-4% among treated population. Meta-analysis of observational studies have demonstrated that pseudo-RH from white coat HTN or medication nonadherence is as much common as the truly RH. Thus, screening for pseudo-resistance in the evaluation of all apparent RH is of utmost importance as diagnosis of white-coat HTN requires no treatment, while medication nonadherence would benefit from identifying and targeting barriers to adherence.

Stability of 21 Antihypertensive Drugs in Serum Collected in Standard (Nongel) Serum Tubes Versus Tubes Containing a Gel Separator

Background:

Therapeutic drug monitoring of antihypertensive drugs is being increasingly used to optimize treatment and to assess nonadherence. Separator gels are often used in blood collection tubes to facilitate serum or plasma separation from other blood constituents before analyses. Drug adsorption into the separator gel presents a possible pre-analytical cause of falsely low concentrations or false negative results.

Methods:

Drug-free blood from blood donors was spiked with therapeutic concentrations of 21 antihypertensive drugs, transferred to serum tubes with and without separator gel (Vacuette gel plastic tubes and plain serum plastic tubes, respectively), and centrifuged. Serum was collected immediately after centrifugation and after 24 and 72 hours of room temperature storage, samples were analyzed in triplicates using liquid chromatography–mass spectrometry.

Results:

Serum samples collected immediately after centrifugation or 24 hours later, had the same drug concentrations in the gel and nongel tubes. After 72 hours of room temperature storage, verapamil and lercanidipine serum concentrations were 43% and 29%, respectively, lower in gel tubes than nongel tubes. Canrenone, diltiazem, and bendroflumethiazide showed between 10% and 20% concentration loss in gel tubes, compared with nongel tubes, with the 2 latter observed as unstable also in nongel tubes.

Conclusions:

Except for verapamil, lercanidipine, and canrenone, which showed substantial concentration loss in gel tubes, gel tubes may be used for therapeutic drug monitoring purposes for the most commonly used antihypertensive drugs. Transferring serum to gel-free containers immediately after centrifugation minimizes concentration loss; however, bendroflumethiazide and diltiazem are generally unstable at room temperature.

Therapeutic Drug Monitoring to Assess Drug Adherence in Assumed Resistant Hypertension: A Comparison With Directly Observed Therapy in 3 Nonadherent Patients

Resistant hypertension is a common health problem leading to suboptimal cardiovascular prevention. A large number of patients with resistant hypertension have poor medication adherence explaining their assumed resistance to therapy. We combined directly observed therapy (DOT) with therapeutic drug monitoring (TDM) in 3 patients at several time points to enable an extensive feedback on blood pressure (BP) and drug levels. BP was measured with an automatic oscillatory device at regular intervals of 5 minutes (directly before and after drug intake) and at 30-minute intervals (at night) during admission. Blood samples were obtained at different time points (t = in hours; t = 0, 2, 4, 6, 12, and 24 hours after drug intake). DOT was performed under supervision of the physician. In 2 of the 3 patients, automated BP decreased directly after DOT, -10/0 and -5/-5 mm Hg, respectively. Plasma drug levels for several drugs or active metabolites were 0 at t = 0, whereas plasma levels were positive at t = 24 hours after observed intake. We recommend a more frequent use of TDM combined with repeated BP measurements in clinical practice because this is a convenient, objective method of measurement and to ensure that actual drug levels reflect the BP at the time of measurement.

Therapeutic drug monitoring-guided definition of adherence profiles in resistant hypertension and identification of predictors of poor adherence

AIMS

Arterial hypertension is an important cardiovascular risk factor. A substantial proportion of patients show resistance to antihypertensive treatment but poor adherence to medication regimens is also a significant cause of treatment failure. In this context, therapeutic drug monitoring (TDM) could be useful. The objective of this study was to assess adherence to treatment in patients with resistant hypertension by TDM and to identify parameters that predict nonadherence.

METHODS

Liquid chromatography tandem mass spectrometry was used to quantify a wide panel of antihypertensive drugs in human plasma to assess treatment compliance. Associations between TDM-determined adherence profiles, self-reported adherence and other patient-related clinical, anthropometric or demographic features were evaluated as potentially useful pre-TDM predictors of poor adherence.

RESULTS

TDM was performed on 50 patients with suspected resistant hypertension: 24% of patients partially complied to treatment and 18% were nonadherent. No concordance was observed with questionnaire results, while nonadherence was associated with high diastolic blood pressure, high heart rate, previous onset of stroke and previous use of invasive treatments, including renal denervation or baroreceptor stimulation.

CONCLUSIONS

This evidence highlights the high prevalence of poor adherence in patients with resistant hypertension and the need for caution in using invasive approaches. These preliminary data require validation in a larger cohort, to confirm the need for TDM in routine clinical practice.

Heart rate is a useful marker of adherence to beta-blocker treatment in hypertension

OBJECTIVES

Suboptimal medication adherence is common among patients with hypertension. Measurements of plasma or urinary levels of antihypertensive drugs are useful, but not widely available. The aim of our study was to investigate the relation of patients' heart rates to their serum beta-blocker levels.

METHODS

We correlated 220 measurements of serum beta-blocker levels in 106 patients with apparently resistant hypertension to their corresponding office heart rate. A significant proportion, 44.6% of patients, were non-adherent to beta-blocker treatment according to serum level measurement. Non-adherent patients had significantly higher heart rates (80.9 vs. 66.6 bpm, p < .001), systolic (157.4 vs. 147.0 mm Hg, p = .002) and diastolic blood pressure (91.1 vs. 87.2 mm Hg, p = .041) in comparison to adherent patients.

RESULTS

Heart rate above 75.5 beats per minute predicted non-adherence to beta-blocker treatment with a sensitivity of 62.5%, specificity 86.8% and AUC ROC 0.802 (p < .001). Higher heart rate cutoff might be applicable for nebivolol but was not determined due to the low number of patients treated with nebivolol.

CONCLUSIONS

We concluded that heart rate was shown to be a good predictor of non-adherence to beta-blocker treatment, and might become a quick and easy measure to determine patient adherence in hypertensive patients.

UHPLC-MS/MS method with sample dilution to test therapeutic adherence through quantification of ten antihypertensive drugs in urine samples

Nowadays, hypertension represents an important health problem, particularly in developed countries. In some cases the standard therapeutic approaches are not able to reestablish the normal blood pressure values: this condition is called "resistant hypertension". However, a fraction of cases of resistant hypertension are actually due to poor adherence to the prescribed therapy. Therapeutic Drug Monitoring could represent a direct and useful tool to correctly identify non-compliant patients. Nevertheless, high throughput methods for the simultaneous monitoring of a wide panel of drugs in the same analysis are lacking and, furthermore, there is not a generally acknowledged "standard" matrix for this test (plasma or urine). In this work, we validated a UHPLC-MS/MS assay to quantify ten among the most used antihypertensive agents in urine samples, covering all the current classes: amlodipine, atenolol, clonidine, chlortalidone, doxazosin, hydrochlorothiazide, nifedipine, olmesartan, ramipril and telmisartan. Both standards and quality controls were prepared in urine matrix. Only 100μL of each sample were added with 40μL of internal standard and 860μL of water:acetonitrile 90:10, acidified with 0.05% formic acid. Chromatographic separation was performed on an Acquity^® UPLC HSS T3 1.8μm 2.1×150mm column, with a gradient of water and acetonitrile, both added with 0.05% formic acid. Accuracy, intra-day and inter-day precision fitted FDA guidelines for all analytes, while matrix effects resulted reproducible among different urine lots. Method performances were tested on urine samples from hypertensive patients with good results. This simple analytical method could represent a useful tool for the management of antihypertensive therapy.

How to Screen for Non-Adherence to Antihypertensive Therapy

The quality of assessment of non-adherence to treatment in hypertensive is poor. Within this review, we discuss the different methods used to assess adherence to blood-pressure-lowering medications in hypertension patients. Subjective reports such as physicians' perceptions are inaccurate, and questionnaires completed by patients tend to overreport adherence and show a low diagnostic specificity. Indirect objective methods such as pharmacy database records can be useful, but they are limited by the robustness of the recorded data. Electronic medication monitoring devices are accurate but usually track adherence to only a single medication and can be expensive. Overall, the fundamental issue with indirect objective measures is that they do not fully confirm ingestion of antihypertensive medications. Detection of antihypertensive medications in body fluids using liquid chromatography-tandem mass spectrometry is currently, in our view, the most robust and clinically useful method to assess non-adherence to blood-pressure-lowering treatment. It is particularly helpful in patients presenting with resistant, refractory or uncontrolled hypertension despite the optimal therapy. We recommend using this diagnostic strategy to detect non-adherence alongside a no-blame approach tailoring support to address the perceptions (e.g. beliefs about the illness and treatment) and practicalities (e.g. capability and resources) influencing motivation and ability to adhere.

Adherence to antihypertensive therapy and therapeutic dosage of antihypertensive drugs

Adherence to antihypertensive therapy is critical to achieving adequate blood pressure control. About half of hypertensive patients do not take their drugs as directed and the physicians often underestimate this issue. Non-adherence has important public health economic implications (numbers of visits, diagnostic procedures, prescribed drugs) and, moreover, it results in increased morbidity and mortality rates. Poor adherence can have several patients and therapy related causes. Currently, multiple different direct and indirect methods to measure therapeutic adherence are available, but, in clinical practice, there is no cost-effective and simple one. Therapeutic drug monitoring (TDM), characterized by drug (or metabolites) concentration measurement in body fluids (blood or urine), is a cost-effective direct method to assess therapeutic adherence. Despite some limitations, TDM may decrease health costs, by reducing the number of visits and by identifying those patients who would undergo unnecessary invasive procedures. Moreover, TDM can be a new alternative method to identify patients with true resistant hypertension, improving the achievement of blood pressure control In this minor revision, we would assess poor therapeutic adherence in hypertensive population, analyzing the different direct and direct available methods, with emphasis on TDM.

Clinical Diagnosis and Management of Resistant Hypertension

Resistant hypertension (RHT) is variably defined as insufficient blood pressure (BP) response to multiple drug treatment. Prevalence of RHT has been thoroughly studied in the recent years, ranging from about 5 to 30 % in various cohorts. Initial management of patients with apparent RHT requires identification of true treatment resistance by out-of-office BP measurements, assessment of adherence and screening for treatable causes of uncontrolled BP. Endorsement of lifestyle modifications and maximisation of the doses of a suitable regimen, preferably with the further addition of an aldosterone antagonist, are the mainstay of treatment. An invasive approach to RHT, mainly represented by renal nerve ablation, should be kept for persistently severe cases managed in a specialised hypertension centre.

Screening for non-adherence to antihypertensive treatment as a part of the diagnostic pathway to renal denervation

Renal denervation is a potential therapeutic option for resistant hypertension. A thorough clinical assessment to exclude reversible/spurious causes of resistance to antihypertensive therapy is required prior to this procedure. The extent to which non-adherence to antihypertensive treatment contributes to apparent resistance to antihypertensive therapy in patients considered for renal denervation is not known. Patients (n=34) referred for renal denervation entered the evaluation pathway that included screening for adherence to antihypertensive treatment by high-performance liquid chromatography-tandem mass spectrometry-based urine analysis. Biochemical non-adherence to antihypertensive treatment was the most common cause of non-eligibility for renal denervation-23.5% of patients were either partially or completely non-adherent to prescribed antihypertensive treatment. About 5.9% of those referred for renal denervation had admitted non-adherence prior to performing the screening test. Suboptimal pharmacological treatment of hypertension and 'white-coat effect' accounted for apparently resistant hypertension in a further 17.7 and 5.9% of patients, respectively. Taken together, these three causes of pseudo-resistant hypertension accounted for 52.9% of patients referred for renal denervation. Only 14.7% of referred patients were ultimately deemed eligible for renal denervation. Without biochemical screening for therapeutic non-adherence, the eligibility rate for renal denervation would have been 38.2%. Non-adherence to antihypertensive treatment and other forms of therapeutic pseudo-resistance are by far the most common reason of 'resistant hypertension' in patients referred for renal denervation. We suggest that inclusion of biochemical screening for non-adherence to antihypertensive treatment may be helpful in evaluation of patients with 'resistant hypertension' prior to consideration of renal denervation.

Cost-Effectiveness of Therapeutic Drug Monitoring in Diagnosing Primary Aldosteronism in Patients With Resistant Hypertension

Primary aldosteronism (PA) is present in up to 20% of patients with treatment-resistant hypertension (TRH). Investigation for PA in patients with TRH is recommended by current guidelines after medication nonadherence is excluded. Studies using therapeutic drug monitoring (TDM) have shown that >50% of patients with TRH are nonadherent to their prescribed antihypertensive medications. However, the relationship between the prevalence of PA and medication adherence as confirmed by TDM has not been previously assessed. A retrospective analysis from a hypertension referral clinic showed that prevalence of PA in adherent patients with TRH by TDM was significantly higher than in nonadherent patients (28% vs 8%, P<.05). Furthermore, cost analysis showed that TDM-guided PA screening was $590.69 less expensive per patient, with minimal impact on the diagnostic accuracy. These data support a TDM-guided PA screening approach as a cost-saving strategy compared with routine PA screening for TRH.

Renal sympathetic denervation after Symplicity HTN-3 and therapeutic drug monitoring in severe hypertension

Renal sympathetic denervation (RDN) has been and is still proposed as a new treatment modality in patients with apparently treatment resistant hypertension (TRH), a condition defined as persistent blood pressure elevation despite prescription of at least 3 antihypertensive drugs including a diuretic. However, the large fall in blood pressure after RDN reported in the first randomized study, Symplicity HTN-2 and multiple observational studies has not been confirmed in five subsequent prospective randomized studies and may be largely explained by non-specific effects such as improvement of drug adherence in initially poorly adherent patients (the Hawthorne effect), placebo effect and regression to the mean. The overall blood-pressure lowering effect of RDN seems rather limited and the characteristics of true responders are largely unknown. Accordingly, RDN is not ready for clinical practice. In most patients with apparently TRH, drug monitoring and improvement of drug adherence may prove more effective and cost-beneficial to achieve blood pressure control. In the meantime, research should aim at identifying characteristics of those patients with truly TRH who may respond to RDN.

Renal Denervation After Symplicity HTN-3 - Back to Basics. Review of the Evidence

Renal sympathetic denervation (RDN) has been proposed as a new treatment modality in patients with apparent treatment resistant hypertension, a condition defined as office blood pressure elevation despite prescription of at least three antihypertensive drugs including a diuretic. However, the impressive fall in blood pressure reported after RDN in Symplicity HTN-2, the first randomised study, and multiple observational studies has not been confirmed in the US sham-controlled trial Symplicity HTN-3 and four subsequent prospective randomised studies, all published or presented in 2014. The blood pressure reduction documented in earlier studies may be largely due to non-specific effects such as improvement of drug adherence in initially poorly adherent patients (Hawthorne effect), placebo effect and regression to the mean. The overall blood pressure lowering effect of RDN seems rather limited and the characteristics of true responders remain largely unknown. Accordingly, RDN is not ready for clinical practice. In most patients with apparent drug-resistant hypertension, drug monitoring and subsequent improvement of drug adherence may prove more effective and cost-beneficial to achieve blood pressure control. In the meantime, research should aim at identifying characteristics of those few patients adherent to drug treatment and with true resistant hypertension who may respond to RDN.