Clinical Value of Emerging Bioanalytical Methods for Drug Measurements: A Scoping Review of Their Applicability for Medication Adherence and Therapeutic Drug Monitoring

Can we Predict Drug Excretion into Saliva? A Systematic Review and Analysis of Physicochemical Properties

BACKGROUND AND OBJECTIVES

Saliva is a patient-friendly matrix for therapeutic drug monitoring (TDM) but is infrequently used in routine care. This is due to the uncertainty of saliva-based TDM results to inform dosing. This study aimed to retrieve data on saliva-plasma concentration and subsequently determine the physicochemical properties that influence the excretion of drugs into saliva to increase the foundational knowledge underpinning saliva-based TDM.

METHODS

Medline, Web of Science and Embase (1974-2023) were searched for human clinical studies, which determined drug pharmacokinetics in both saliva and plasma. Studies with at least ten subjects and five paired saliva-plasma concentrations per subject were included. For each study, the ratio of the area under the concentration-time curve between saliva and plasma was determined to assess excretion into saliva. Physicochemical properties of each drug (e.g. pKa, lipophilicity, molecular weight, polar surface area, rotatable bonds and fraction of drug unbound to plasma proteins) were obtained from PubChem and Drugbank. Drugs were categorised by their ionisability, after which saliva-to-plasma ratios were predicted with adjustment for protein binding and physiological pH via the Henderson-Hasselbalch equation. Spearman correlation analyses were performed for each drug category to identify factors predicting saliva excretion (α = 5%). Study quality was assessed by the risk of bias in non-randomised studies of interventions tool.

RESULTS

Overall, 42 studies including 40 drugs (anti-psychotics, anti-microbials, immunosuppressants, anti-thrombotic, anti-cancer and cardiac drugs) were included. The median saliva-to-plasma ratios were similar for drugs in the amphoteric (0.59), basic (0.43) and acidic (0.41) groups and lowest for drugs in the neutral group (0.21). Higher excretion of acidic drugs (n = 5) into saliva was associated with lower ionisation and protein binding (correlation between predicted versus observed saliva-to-plasma ratios: R2 = 0.85, p = 0.02). For basic drugs (n = 21), pKa predicted saliva excretion (Spearman correlation coefficient: R = 0.53, p = 0.02). For amphoteric drugs (n = 10), hydrogen bond donor (R = - 0.76, p = 0.01) and polar surface area (R = - 0.69, p = 0.02) were predictors. For neutral drugs (n = 10), protein binding (R = 0.84, p = 0.004), lipophilicity (R = - 0.65, p = 0.04) and hydrogen bond donor count (R = - 0.68, p = 0.03) were predictors. Drugs considered potentially suitable for saliva-based TDM are phenytoin, tacrolimus, voriconazole and lamotrigine. The studies had a low-to-moderate risk of bias.

CONCLUSIONS

Many commonly used drugs are excreted into saliva, which can be partly predicted by a drug's ionisation state, protein binding, lipophilicity, hydrogen bond donor count and polar surface area. The contribution of drug transporters and physiological factors to the excretion needs to be evaluated. Continued research on drugs potentially suitable for saliva-based TDM will aid in adopting this person-centred TDM approach to improve patient outcomes.

Medication adherence to CFTR modulators in patients with cystic fibrosis: a systematic review

BACKGROUND

In the last decade, a fundamental shift in the treatment of cystic fibrosis (CF) took place due to the introduction of CF transmembrane conductance regulator (CFTR) modulators. Adequate medication adherence is a prerequisite for their effectiveness, but little is known about adherence to CFTR modulators. We aimed to assess the extent of medication adherence to CFTR modulators in patients with CF and assess which characteristics are associated with adherence.

METHODS

A systematic review following PRISMA guidelines was performed. Studies needed to report adherence to CFTR modulators. Main outcomes were: 1) level of medication adherence and 2) associations of demographic and/or clinical characteristics with adherence.

RESULTS

In total, 4082 articles were screened and 21 full-text papers were assessed for eligibility. Ultimately, seven studies were included. Most studies were retrospective and focused on adherence to ivacaftor or lumacaftor-ivacaftor with only one focusing on elexacaftor-tezacaftor-ivacaftor. The majority used pharmacy refill data with adherence determined with the proportion of days covered (PDC) or the medication possession ratio (MPR). One study additionally used electronic monitoring and patient self-reported adherence. Adherence was 0.62-0.99 based on pharmacy data (PDC or MPR), 61% via electronic monitoring and 100% via self-report. Age <18 years appeared to be associated with good adherence, as was a higher lung function.

CONCLUSIONS

Despite the wide variety of adherence methods used, adherence to CFTR modulators is suboptimal, based on objective measures such as pharmacy refill data or electronic monitoring. CFTR modulator adherence measurement and definitions requires more standardisation with a preference for objective and granular methods.

Therapeutic drug monitoring guidelines in oncology: what do we know and how to move forward? Insights from a systematic review

Background

Compared with anti-infective drugs, immunosuppressants and other fields, the application of therapeutic drug monitoring (TDM) in oncology is somewhat limited.

Objective

We aimed to provide a comprehensive understanding of TDM guidelines for antineoplastic drugs and to promote the development of individualized drug therapy in oncology.

Design

This study type is a systematic review.

Data sources and methods

This study was performed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 statement. Databases including PubMed, Embase, the official websites of TDM-related associations and Chinese databases were comprehensively searched up to March 2023. Two investigators independently screened the literature and extracted data. The methodological and reporting quality was evaluated using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) and the Reporting Items for Practice Guidelines in Healthcare (RIGHT), respectively. Recommendations and quality evaluation results were presented by visual plots. This study was registered in PROSPERO (No. CRD42022325661).

Results

A total of eight studies were included, with publication years ranging from 2014 to 2022. From the perspective of guideline development, two guidelines were developed using evidence-based methods. Among the included guidelines, four guidelines were for cytotoxic antineoplastic drugs, three for small molecule kinase inhibitors, and one for antineoplastic biosimilars. Currently available guidelines and clinical practice provided recommendations of individualized medication in oncology based on TDM, as well as influencing factors. With regard to methodological quality based on AGREE II, the average overall quality score was 55.21%. As for the reporting quality by RIGHT evaluation, the average reporting rate was 53.57%.

Conclusion

From the perspective of current guidelines, TDM in oncology is now being expanded from cytotoxic antineoplastic drugs to newer targeted treatments. Whereas, the types of antineoplastic drugs involved are still small, and there is still room for quality improvement. Furthermore, the reflected gaps warrant future studies into the exposure-response relationships and population pharmacokinetics models.

Salivary Therapeutic Drug Monitoring of Antimicrobial Therapy: Feasible or Futile?

Personalised drug dosing through therapeutic drug monitoring (TDM) is important to maximise efficacy and to minimise toxicity. Hurdles preventing broad implementation of TDM in routine care include the need of sophisticated equipment and highly trained staff, high costs and lack of timely results. Salivary TDM is a non-invasive, patient-friendly alternative to blood sampling, which has the potential to overcome barriers with traditional TDM. A mobile UV spectrophotometer may provide a simple solution for analysing drug concentrations in saliva samples. Salivary TDM utilising point-of-care tests can support personalised dosing in various settings including low-resource as well as remote settings. In this opinion paper, we describe how hurdles of implementing traditional TDM may be mitigated by salivary TDM with new strategies for patient-friendly point-of-care testing.

Prevalence of medication adherence and glycemic control among patients with type 2 diabetes and influencing factors: A cross-sectional study

Background

This study aimed to assess medication adherence, glycemic control, and their influencing factors among outpatients at an Indonesian clinic with type 2 diabetes.

Methods

A cross-sectional study was conducted among patients with type 2 diabetes at a hospital-based clinic in Surabaya, Indonesia, from September to December 2018. A purposive sampling was used; patients aged 18 years and older, had diabetes and any comorbidity, received hypoglycemic agents, and provided written informed consent were included. The previously validated Brief Medication Questionnaire was used to measure medication adherence, while glycosylated hemoglobin (A1C) levels were used to evaluate glycemic control. Binary logistic regression was used to identify factors associated with medication adherence and glycemic control.

Results

Of 321 patients enrolled in the study, 268 (83.5%) patients were medication nonadherent. Patients who did not engage regularly in physical activity (aOR: 0.49, 95% CI: 0.26-0.93) was more likely to be medication adherent. Poor glycemic control (A1C: >7%) was observed in 106 (33.0%) of the patients. Patients who used a combination of oral hypoglycemic agents and insulin (aOR: 2.74, 95% CI: 1.09-6.86), did not take biguanide (aOR: 2.73, 95% CI: 1.16-6.43), reported hyperglycemia (aOR: 4.24, 95% CI: 1.53-11.81), and had comorbid diseases (aOR: 4.33, 95% CI: 1.08-17.34) increased the risk of having poor glycemic control. Patients who were more likely to achieve good glycemic control were male (aOR: 0.39, 95% CI: 0.20-0.74) and aged older (aOR: 0.95, 95% CI: 0.92-0.99).

Conclusions

The proportion of patients who were medication nonadherent was much higher than those with poor glycemic control. Whereas regular exercise was a predictor of nonadherence, age, sex, diabetes medication, not taking biguanide, acute complications, and comorbidity were predictors of poor glycemic control. Therefore, strategies are needed to improve medication adherence and glycemic control.

Psychometric Properties of a Machine Learning-Based Patient-Reported Outcome Measure on Medication Adherence: Single-Center, Cross-Sectional, Observational Study

BACKGROUND

Medication adherence plays a critical role in controlling the evolution of chronic disease, as low medication adherence may lead to worse health outcomes, higher mortality, and morbidity. Assessment of their patients' medication adherence by clinicians is essential for avoiding inappropriate therapeutic intensification, associated health care expenditures, and the inappropriate inclusion of patients in time- and resource-consuming educational interventions. In both research and clinical practices the most extensively used measures of medication adherence are patient-reported outcome measures (PROMs), because of their ability to capture subjective dimensions of nonadherence. Machine learning (ML), a subfield of artificial intelligence, uses computer algorithms that automatically improve through experience. In this context, ML tools could efficiently model the complexity of and interactions between multiple patient behaviors that lead to medication adherence.

OBJECTIVE

This study aimed to create and validate a PROM on medication adherence interpreted using an ML approach.

METHODS

This cross-sectional, single-center, observational study was carried out a French teaching hospital between 2021 and 2022. Eligible patients must have had at least 1 long-term treatment, medication adherence evaluation other than a questionnaire, the ability to read or understand French, an age older than 18 years, and provided their nonopposition. Included adults responded to an initial version of the PROM composed of 11 items, each item being presented using a 4-point Likert scale. The initial set of items was obtained using a Delphi consensus process. Patients were classified as poorly, moderately, or highly adherent based on the results of a medication adherence assessment standard used in the daily practice of each outpatient unit. An ML-derived decision tree was built by combining the medication adherence status and PROM responses. Sensitivity, specificity, positive and negative predictive values (NPVs), and global accuracy of the final 5-item PROM were evaluated.

RESULTS

We created an initial 11-item PROM with a 4-point Likert scale using the Delphi process. After item reduction, a decision tree derived from 218 patients including data obtained from the final 5-item PROM allowed patient classification into poorly, moderately, or highly adherent based on item responses. The psychometric properties were 78% (95% CI 40%-96%) sensitivity, 71% (95% CI 53%-85%) specificity, 41% (95% CI 19%-67%) positive predictive values, 93% (95% CI 74%-99%) NPV, and 70% (95% CI 55%-83%) accuracy.

CONCLUSIONS

We developed a medication adherence tool based on ML with an excellent NPV. This could allow prioritization processes to avoid referring highly adherent patients to time- and resource-consuming interventions. The decision tree can be easily implemented in computerized prescriber order-entry systems and digital tools in smartphones. External validation of this tool in a study including a larger number of patients with diseases associated with low medication adherence is required to confirm its use in analyzing and assessing the complexity of medication adherence.

Half a Century of Fragmented Research on Deviations from Advised Therapies: Is This a Good Time to Call for Multidisciplinary Medication Adherence Research Centres of Excellence?

Medication adherence is a key precondition of the effectiveness of evidence-based therapies. However, in real-life settings, non-adherence to medication is still very common. This leads to profound health and economic consequences at both individual and public health levels. The problem of non-adherence has been extensively studied in the last 50 years. Unfortunately, with more than 130,000 scientific papers published on that subject so far, we are still far from finding an ultimate solution. This is, at least partly, due to fragmented and poor-quality research that has been conducted in this field sometimes. To overcome this deadlock, there is a need to stimulate the adoption of best practices in medication adherence-related research in a systematic way. Therefore, herein we propose the establishment of dedicated medication adherence research Centres of Excellence (CoEs). These Centres could not only conduct research but could also create a profound societal impact, directly serving the needs of patients, healthcare providers, systems and economies. Additionally, they could play a role as local advocates for good practices and education. In this paper, we propose some practical steps that might be taken in order to establish such CoEs. We describe two success stories, i.e., Dutch and Polish Medication Adherence Research CoEs. The COST Action "European Network to Advance Best practices & technoLogy on medication adherencE" (ENABLE) aims to develop a detailed definition of the Medication Adherence Research CoE in the form of a list of minimal requirements regarding their objectives, structure and activities. We hope that it will help to create a critical mass and catalyse the setup of regional and national Medication Adherence Research CoEs in the near future. This, in turn, may not only increase the quality of the research but also raise the awareness of non-adherence and promote the adoption of the best medication adherence-enhancing interventions.

Current Status of Therapeutic Drug Monitoring in Mental Health Treatment: A Review

Therapeutic drug monitoring (TDM) receives growing interest in different psychiatric clinical settings (emergency, inpatient, and outpatient services). Despite its usefulness, TDM remains underemployed in mental health. This is partly due to the need for evidence about the relationship between drug serum concentration and efficacy and tolerability, both in the general population and even more in subpopulations with atypical pharmacokinetics. This work aims at reviewing the scientific literature published after 2017, when the most recent guidelines about the use of TDM in mental health were written. We found 164 pertinent records that we included in the review. Some promising studies highlighted the possibility of correlating early drug serum concentration and clinical efficacy and safety, especially for antipsychotics, potentially enabling clinicians to make decisions on early laboratory findings and not proceeding by trial and error. About populations with pharmacokinetic peculiarities, the latest studies confirmed very common alterations in drug blood levels in pregnant women, generally with a progressive decrease over pregnancy and a very relevant dose-adjusted concentration increase in the elderly. For adolescents also, several drugs result in having different dose-related concentration values compared to adults. These findings stress the recommendation to use TDM in these populations to ensure a safe and effective treatment. Moreover, the integration of TDM with pharmacogenetic analyses may allow clinicians to adopt precise treatments, addressing therapy on an individual pharmacometabolic basis. Mini-invasive TDM procedures that may be easily performed at home or in a point-of-care are very promising and may represent a turning point toward an extensive real-world TDM application. Although the highlighted recent evidence, research efforts have to be carried on: further studies, especially prospective and fixed-dose, are needed to replicate present findings and provide clearer knowledge on relationships between dose, serum concentration, and efficacy/safety.

Second and Third Generational Advances in Therapies of the Immune-Mediated Kidney Diseases in Children and Adolescents

Therapy of immune-mediated kidney diseases has evolved during recent decades from the non-specific use of corticosteroids and antiproliferative agents (like cyclophosphamide or azathioprine), towards the use of more specific drugs with measurable pharmacokinetics, like calcineurin inhibitors (cyclosporine A and tacrolimus) and mycophenolate mofetil, to the treatment with biologic drugs targeting detailed specific receptors, like rituximab, eculizumab or abatacept. Moreover, the data coming from a molecular science revealed that several drugs, which have been previously used exclusively to modify the upregulated adaptive immune system, may also exert a local effect on the kidney microstructure and ameliorate the functional instability of podocytes, reducing the leak of protein into the urinary space. The innate immune system also became a target of new therapies, as its specific role in different kidney diseases has been de novo defined. Current therapy of several immune kidney diseases may now be personalized, based on the detailed diagnostic procedures, including molecular tests. However, in most cases there is still a space for standard therapies based on variable protocols including usage of steroids with the steroid-sparing agents. They are used as a first-line treatment, while modern biologic agents are selected as further steps in cases of lack of the efficacy or toxicity of the basic therapies. In several clinical settings, the biologic drugs are effective as the add-on therapy.

Detecting, preventing, and treating non-adherence to immunosuppression after kidney transplantation

Medication non-adherence (MNA) is a major issue in kidney transplantation and it is associated with increased risk of rejection, allograft loss, patients’ death and higher healthcare costs. Despite its crucial importance, it is still unclear what are the best strategies to diagnose, prevent and treat MNA. MNA can be intentional (deliberate refusal to take the medication as prescribed) or unintentional (non-deliberate missing the prescribed medication). Its diagnosis may rely on direct methods, aiming at measuring drug ingestions, or indirect methods that analyse the habits of patients to adhere to correct drug dose (taking adherence) and interval (time adherence). Identifying individual risk factors for MNA may provide the basis for a personalized approach to the treatment of MNA. Randomized control trials performed so far have tested a combination of strategies, such as enhancing medication adherence through the commitment of healthcare personnel involved in drug distribution, the use of electronic reminders, therapy simplification or various multidisciplinary approaches to maximize the correction of individual risk factors. Although most of these approaches reduced MNA in the short-term, the long-term effects on MNA and, more importantly, on clinical outcomes remain unclear. In this review, we provide a critical appraisal of traditional and newer methods for detecting, preventing and treating non-adherence to immunosuppression after kidney transplantation from the perspective of the practising physician.

Electronic Smart Blister Packages to Monitor and Support Medication Adherence: A Usability Study

PURPOSE

An electronic version of the Dosepak^® (EDP) which records date and time of dosing events has been developed to monitor adherence to medication packaged in blisters. This study aimed to evaluate its usability and acceptance and to monitor dose-taking adherence for optimal implementation in future clinical trials and practice.

METHODS

Healthy volunteers aged over 18 years were asked to dispense placebo tablets twice daily from EDPs equipped with a re-usable electronic module for a total duration of four weeks. Afterwards, subjects were asked to complete an online questionnaire and partake in a short one-on-one interview. The usability of the EDP was assessed using the System Usability Scale (SUS), while dose-taking adherence was monitored by EDP records, pill counting, and self-report. The short interview explored user experiences in more detail.

RESULTS

Twenty subjects with median [IQR] age 41.5 [32-49.8] years, 55% female, 45% healthcare professionals, and 20% chronic medication users completed the study and found the EDP easy to use, with a mean [SD] SUS score of 78.0 [11.2]. Median [IQR] dose-taking adherence was 89% [82-95%] based on EDP records, 96.5% [89-100%] based on pill counting, 92% [91-96%] based on self-report, and the levels differed significantly (p < 0.05). Four themes emerged from the interviews: user preference, experience, patient burden, and ideas for improvement. Most participants preferred smaller sized blisters. They found the EDP simple to use and did not see any patient burden for its use in trials or clinical practice. Some reported forgetfulness and suggested reminders built into the blister or sent to their mobile phones. Adequate information or instruction should also be provided for older people and polypharmacy patients.

CONCLUSION

EDP had good perceived usability, was well accepted, and differed significantly from other adherence measurement methods. This study provides input to further guide scale-up of the blister packages.