Development and Validation of a Dried Blood Spot Assay Using UHPLC-MS/MS to Identify and Quantify 12 Antihypertensive Drugs and 4 Active Metabolites: Clinical Needs and Analytical Limitations

Quality-of-life and beliefs about medication in relation to a therapy adherence intervention in resistant hypertension: the Resistant HYpertension: MEasure to ReaCh Targets trial

OBJECTIVE

To assess the impact of personalized feedback on therapy adherence testing results on quality of life and beliefs about medication in patients with resistant hypertension, as well as to identify patient-oriented predictors of therapy adherence.

METHODS

This study was a prespecified post hoc analysis of the multicenter randomized controlled trial Resistant HYpertension: MEasure to ReaCh Targets (RHYME-RCT). Patients were randomized to a personalized feedback conversation on measured antihypertensive drug levels additional to standard-of-care, or standard-of-care only. The primary outcomes consisted of EuroQol EQ-5D-5L and Beliefs about Medicine Questionnaire (BMQ) scores at 12 months.

RESULTS

A total of 56 patients with median age 61.5 [25th-75th percentile: 55.8-69.3] years (21.4% women) were included. Mean blood pressure ±SD was 149.8/84.1 ± 14.9/13.8 mmHg while being on a median of 5.6 [4.8-7.3] defined daily dosages (DDD) of antihypertensive drugs. At 12 months, no differences were observed in EQ-5D-5L index (0.81 [0.69-0.89] vs. 0.89 [0.73-1.00]; P  = 0.18) and visual analogue scale score on general patient-perceived health (70 [60-80] vs. 70 [60-82]; P  = 0.53) between the intervention-arm and the standard-of-care only-arm. Likewise, individual EQ-5D-5L domain scores and BMQ scores did not differ between both arms. Irrespective of the intervention, independent positive predictors of the percentage adherence were patient age, EQ-5D-5L index score, BMQ-specific necessity score and concern score, whereas the total number of drugs prescribed was a negative predictor.

CONCLUSION

Within this prespecified subanalysis of the randomized RHYME-RCT trial, implementation of a personalized feedback conversation targeting therapy adherence did not improve health-related quality-of-life and beliefs about medication in patients with resistant hypertension.

'Under pressure': The role of therapeutic drug monitoring in the treatment of hypertension

Antihypertensive drugs do not qualify as optimal candidates for therapeutic drug monitoring (TDM), given their obvious physiological effect, the absence of a clear relationship between drug concentrations and pharmacodynamic outcomes and their wide therapeutic range. However, since non-adherence is a major challenge in hypertension management, using drug concentrations can be of value to identify non-adherence as a first step towards better blood pressure control. In this article we discuss the key challenges associated with measuring and interpreting antihypertensive drug concentrations that are important when TDM is used to improve non-adherence. Additionally, we elaborate on the role of TDM in optimizing antihypertensive drug treatment besides addressing non-adherence by highlighting its value in specific patient groups with altered pharmacokinetic parameters such as female vs. male or elderly patients.

Dried blood spot analysis for the quantification of vancomycin and creatinine using liquid chromatography - tandem mass spectrometry: Method development and validation

BACKGROUND

Vancomycin is a widely used antibiotic for the treatment of gram-positive bacterial infections, especially for methicillin-resistant Staphylococcus aureus (MRSA) infections. Due to a small therapeutic range and large inter-patient variability, therapeutic drug monitoring (TDM) of vancomycin is required to minimize toxicity and maximize treatment efficacy. Venous blood sampling is mostly applied for TDM of vancomycin, although this widely used sampling method is more invasive compared to less painful alternatives, such as the dried blood spot (DBS) method, which can be performed at home.

METHOD

We developed an UPLC-MS/MS method for the quantification of vancomycin and creatinine in DBS. A fast sample preparation and short analysis run time of 5.2 min were applied, which makes this method highly suitable for clinical settings. Validation was performed according to international (FDA and EMA) guidelines.

RESULTS

The validated concentration range was found linear for creatinine from 41.8 µmol/L to 722 µmol/L and for vancomycin from 3.8 mg/L to 76.6 mg/L (r2 > 0.990) and the inaccuracies, imprecisions, hematocrit effects, and recoveries were < 15 % for both compounds. No significant carryover effect was observed.

CONCLUSION

Hence, we successfully validated a quantification method for the simultaneous determination of creatinine and vancomycin in DBS.

Antihypertensive drug concentration measurement combined with personalized feedback in resistant hypertension: a randomized controlled trial

BACKGROUND

Adherence to antihypertensive drugs (AHDs) is crucial for controlling blood pressure (BP). We aimed to determine the effectiveness of measuring AHD concentrations using a dried blood spot (DBS) sampling method to identify nonadherence, combined with personalized feedback, in reducing resistant hypertension.

METHODS

We conducted a multicenter, randomized, controlled trial (RHYME-RCT, ICTRP NTR6914) in patients with established resistant hypertension. Patients were randomized to receive either an intervention with standard of care (SoC) or SoC alone. SoC consisted of BP measurement and DBS sampling at baseline, 3 months (t3), 6 months (t6), and 12 months (t12); AHD concentrations were measured but not reported in this arm. In the intervention arm, results on AHD concentrations were discussed during a personalized feedback conversation at baseline and t3. Study endpoints included the proportion of patients with RH and AHD adherence at t12.

RESULTS

Forty-nine patients were randomized to receive the intervention+SoC, and 51 were randomized to receive SoC alone. The proportion of adherent patients improved from 70.0 to 92.5% in the intervention+SoC arm ( P  = 0.008, n  = 40) and remained the same in the SoC arm (71.4%, n  = 42). The difference in adherence between the arms was statistically significant ( P  = 0.014). The prevalence of resistant hypertension decreased to 75.0% in the intervention+SoC arm ( P  < 0.001, n  = 40) and 59.5% in the SoC arm ( P  < 0.001, n  = 42) at t12; the difference between the arms was statistically nonsignificant ( P  = 0.14).

CONCLUSION

Personalized feedback conversations based on DBS-derived AHD concentrations improved AHD adherence but did not reduce the prevalence of RH.

Monitoring antihypertensive drug concentrations to determine nonadherence in hypertensive patients with or without a kidney transplant

BACKGROUND

Nonadherence to antihypertensive drugs (AHDs) is a major contributor to pseudo-resistant hypertension. The primary objective of this study was to determine the prevalence of nonadherence to AHDs among patients visiting the nephrology and vascular outpatient clinics.

METHODS

Patients were eligible to participate in this prospective observational study if they used at least two AHDs that could be measured with a validated UHPLC-MS/MS method and had an office blood pressure at least 140 and/or at least 90 mmHg. For resistant hypertension, included patients had to use at least three AHDs including a diuretic or four AHDs. Adherence was assessed by measuring drug concentrations in blood. The complete absence of drug in blood was defined as nonadherence. A posthoc analysis was performed to determine the influence of a having a kidney transplant on the adherence rates.

RESULTS

One hundred and forty-two patients were included of whom 66 patients fulfilled the definition of resistant hypertension. The overall adherence rate to AHDs was 78.2% ( n  = 111 patients), with the highest adherence rate for irbesartan (100%, n  = 9) and lowest adherence rate for bumetanide ( n  = 69%, n  = 13). In further analysis, only kidney transplantation could be identified as an important factor for adherence (adjusted odds ratio = 3.35; 95% confidence interval 1.23-9.09). A posthoc analysis showed that patients with a kidney transplant were more likely to be adherent to AHDs (non-KT cohort 64.0% vs. KT-cohort 85.7%, χ 2 (2) = 10.34, P  = 0.006).

CONCLUSION

The adherence rate to AHDs in hypertensive patients was high (78.2%) and even higher after a kidney transplant (85.7%). Furthermore, patients after kidney transplant had a lower risk of being nonadherent to AHDs.

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.

Closing the gap - development of an analytical methodology using volumetric absorptive microsampling of finger prick blood followed by LC-HRMS/MS for adherence monitoring of antihypertensive drugs

Volumetric absorptive microsampling (VAMS), an emerging microsampling technique, is a promising tool for adherence monitoring. This study focused on development of an analytical methodology to improve VAMS-based strategies for adherence assessment by analyzing angiotensin-converting-enzyme (ACE) inhibitors, loop diuretics, a potassium-sparing diuretic, and a thiazide diuretic. Development included sample preparation, chromatographic conditions, mass spectrometry settings, validation, and demonstrating proof of concept. Quantification of analytes, by name furosemide, hydrochlorothiazide, lisinopril, torasemide, and the active metabolites, canrenone, enalaprilat, and ramiprilat in finger prick blood (FPB), was validated based on international guidelines. Selectivity, carryover, and within/between-run accuracy and precision were in accordance with the recommendations. The matrix effect was evaluated at three different hematocrit levels (HT: 20%, 40%, 60%) and the coefficients of variation did not exceed 15%. Dilution integrity (1:10 and 1:20) was given for all analytes except lisinopril, yet for lisinopril, the therapeutic range was already covered by the calibration range. Long-term stability in VAMS tips was tested for 2 weeks at 24 °C in the dark and revealed no degradation of analytes. The proof of concept was performed by analyzing 35 intakes of ACE-inhibitors and diuretics in 18 VAMS and matched plasma samples. Hereby, determined concentration in FPB and plasma cannot be used interchangeably, and thus specific reference ranges for whole blood must be established. Nevertheless, the VAMS-based strategy was shown to be suitable for assessing adherence of all classes of antihypertensive drugs used in the guidelines to manage hypertension.