'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.

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 ±â€Š14.9/13.8 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.

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.