Pharmacogenetic interventions to improve outcomes in patients with multimorbidity or prescribed polypharmacy: a systematic review

Recognizing and preventing unacknowledged prescribing errors associated with polypharmacy

BACKGROUND

Prescribing errors put an enormous burden on health and the economy, claiming implementation of effective methods to prevent/reduce them. Polypharmacy regimens (five or more drugs) are highly prone to unacknowledged prescribing errors, since the complex network of drug-drug interactions, guidelines and contraindications is challenging to be adequately evaluated in the prescription phase, especially if different doctors are involved. Clinical decision support systems aimed at polypharmacy evaluation may be crucial to recognize and correct prescribing errors.

METHODS

A commercial clinical decision support system (Drug-PIN®) was applied to estimate the frequency of unrecognized prescribing errors in a group of 307 consecutive patients accessing the hospital pre-admission service of the Sant'Andrea Hospital of Rome, Italy, in the period April-June 2023. Drug-PIN® is a two-step system, first scoring the risk (low, moderate or high) associated with a certain therapy-patient pair, then allowing therapy optimization by medications exchanges. We defined prescribing errors as cases where therapy optimization could achieve consistent reduction of the Drug-PIN® calculated risk.

RESULTS

Polypharmacy was present in 205 patients, and moderate to high risk for medication harm was predicted by Drug-PIN® in 91 patients (29.6%). In 58 of them (63.7%), Drug-PIN® guided optimization of the therapy could be achieved, with a statistically significant reduction of the calculated therapy-associated risk score. Patients whose therapy cannot be improved have a statistically significant higher number of used drugs. Considering the overall study population, the rate of avoidable prescribing errors was 18.89%.

CONCLUSIONS

Results suggest that computer-aided evaluation of medication-associated harm could be a valuable and actionable tool to identify and prevent prescribing errors in polypharmacy. We conducted the study in a Hospital pre-admission setting, which is not representative of the general population but represents a hotspot to intercept fragile population, where a consistent fraction of potentially harmful polypharmacy regimens could be promptly identified and corrected by systematic use of adequate clinical decision support tools.

A Pharmacogenetic Panel-Based Prediction of the Clinical Outcomes in Elderly Patients with Coronary Artery Disease

Clinical annotations for the actionable pharmacogenetic variants affecting the efficacy of cardiovascular drugs have been collected, yet their impacts on elderly patients with coronary artery disease (CAD) undergoing polypharmacy remain uncertain. We consecutively enrolled 892 elderly patients (mean age 80.7 ± 5.2) with CAD and polypharmacy. All the included patients underwent genotyping for 13 variants in 10 pharmacogenes (CYP2C19, CYP2C9, CYP4F2, CYP2D6, VKORC1, SLCO1B1, APOE, ACE, ADRB1, and MTHFR), which have the clinical annotations for 12 drugs that are commonly prescribed for patients with CAD. We found that 80.3% of the elderly CAD patients had at least one drug-gene pair associated with a therapeutical drug change. After adjusting for covariates, the number of drug-gene pairs was independently associated with a decreased risk of both major cardiovascular events (MACEs) (adjusted hazard ratio [HR]: 0.803, 95% confidence interval [CI]: 0.683-0.945, p = 0.008) and all-cause mortality (adjusted HR: 0.848, 95% CI: 0.722-0.996, p = 0.045), but also with an increased risk of adverse drug reactions (ADRs) (adjusted HR: 1.170, 95% CI: 1.030-1.329, p = 0.016). The Kaplan-Meier survival curves showed that compared to patients without a drug-gene pair, a significantly lower risk of MACEs could be observed in patients with a drug-gene pair during a 4-year follow-up (HR: 0.556, 95% CI: 0.325-0.951, p = 0.013). In conclusion, the carrier status of the actionable drug-gene pair is predictive for the clinical outcomes in elderly patients with CAD and polypharmacy. Implementing early or preemptive pharmacogenetic panel-guided polypharmacy holds the potential to enhance clinical outcomes for these patients.

Haplotype Inference Using Long-Read Nanopore Sequencing: Application to GSTA1 Promoter

Recovering true haplotypes can have important clinical consequences. The laboratory process is difficult and is, therefore, most often done through inference. In this paper, we show that when using the Oxford nanopore sequencing technology, we could recover the true haplotypes of the GSTA1 promoter region. Eight LCL cell lines with potentially ambiguous haplotypes were used to characterize the efficacy of Oxford nanopore sequencing to phase the correct GSTA1 promoter haplotypes. The results were compared to Sanger sequencing and inferred haplotypes in the 1000 genomes project. The average read length was 813 bp out of a total PCR length of 1336 bp. The best coverage of sequencing was in the middle of the PCR product and decreased to 50% at the PCR ends. SNPs separated by less than 200 bp showed > 90% of correct haplotypes, while at the distance of 1089 bp, this proportion still exceeded 58%. The number of cycles influences the generation of hybrid haplotypes but not extension or annealing time. The results demonstrate that this long sequencing reads methodology, can accurately determine the haplotypes without the need for inference. The technology proved to be robust but the success of phasing nonetheless depends on the distances and frequencies of SNPs.

Cumulative Update of a Systematic Overview Evaluating Interventions Addressing Polypharmacy

Importance

Polypharmacy is associated with mortality, falls, hospitalizations, and functional and cognitive decline. The study of polypharmacy-related interventions has increased substantially, prompting the need for an updated, more focused systematic overview.

Objective

To systematically evaluate and summarize evidence across multiple systematic reviews (SRs) examining interventions addressing polypharmacy.

Evidence Review

A search was conducted of MEDLINE, the Cochrane Database of Systematic Reviews, and the Database of Abstracts of Reviews of Effects for articles published from January 2017-October 2022, as well as those identified in a previous overview (January 2004-February 2017). Systematic reviews were included regardless of study design, setting, or outcome. The evidence was summarized by 4 categories: (1) medication-related process outcomes (eg, potentially inappropriate medication [PIM] and potential prescribing omission reductions), (2) clinical and functional outcomes, (3) health care use and economic outcomes, and (4) acceptability of the intervention.

Findings

Fourteen SRs were identified (3 from the previous overview), 7 of which included meta-analyses, representing 179 unique published studies. Nine SRs examined medication-related process outcomes (low to very low evidence quality). Systematic reviews using pooled analyses found significant reductions in the number of PIMs, potential prescribing omissions, and total number of medications, and improvements in medication appropriateness. Twelve SRs examined clinical and functional outcomes (very low to moderate evidence quality). Five SRs examined mortality; all mortality meta-analyses were null, but studies with longer follow-up periods found greater reductions in mortality. Five SRs examined falls incidence; results were predominantly null save for a meta-analysis in which PIMs were discontinued. Of the 8 SRs examining quality of life, most (7) found predominantly null effects. Ten SRs examined hospitalizations and readmissions (very low to moderate evidence quality) and 4 examined emergency department visits (very low to low evidence quality). One SR found significant reductions in hospitalizations and readmissions among higher-intensity medication reviews with face-to-face patient components. Another meta-analysis found a null effect. Of the 7 SRs without meta-analyses for hospitalizations and readmissions, all had predominantly null results. Two of 4 SRs found reductions in emergency department visits. Two SRs examined acceptability (very low evidence quality), finding wide variation in the adoption of polypharmacy-related interventions.

Conclusions and Relevance

This updated systematic overview noted little evidence of an association between polypharmacy-related interventions and reduced important clinical and health care use outcomes. More evidence is needed regarding which interventions are most useful and which populations would benefit most.

Gene Polymorphisms and Drug-Drug Interactions Determine the Metabolic Profile of Blonanserin

This study aimed to evaluate the effects of cytochrome P450 3A4 (CYP3A4) gene polymorphism and drug interaction on the metabolism of blonanserin. Human recombinant CYP3A4 was prepared using the Bac-to-Bac baculovirus expression system. A microsomal enzyme reaction system was established, and drug-drug interactions were evaluated using Sprague-Dawley rats. Ultra-performance liquid chromatography-tandem mass spectrometry was used to detect the concentrations of blonanserin and its metabolite. Compared with wild type CYP34A, the relative clearance of blonanserin by CYP3A4.29 significantly increased to 251.3%, while it decreased notably with CYP3A4.4, 5, 7, 8, 9, 10, 12, 13, 14, 16, 17, 18, 23, 24, 28, 31, 33, and 34, ranging from 6.09% to 63.34%. Among 153 tested drugs, nimodipine, felodipine, and amlodipine were found to potently inhibit the metabolism of blonanserin. Moreover, the inhibitory potency of nimodipine, felodipine, and amlodipine varied with different CYP3A4 variants. The half-maximal inhibitory concentration and enzymatic kinetics assay demonstrated that the metabolism of blonanserin was noncompetitively inhibited by nimodipine in rat liver microsomes and was inhibited in a mixed manner by felodipine and amlodipine in both rat liver microsomes and human liver microsomes. When nimodipine and felodipine were coadministered with blonanserin, the area under the blood concentration-time curve (AUC)(0-t), AUC(0-∞), and C max of blonanserin increased. When amlodipine and blonanserin were combined, the C max of blonanserin C increased remarkably. The vast majority of CYP3A4 variants have a low ability to catalyze blonanserin. With combined administration of nimodipine, felodipine, and amlodipine, the elimination of blonanserin was inhibited. This study provides the basis for individualized clinical use of blonanserin. SIGNIFICANCE STATEMENT: The enzyme kinetics of novel CYP3A4 enzymes for metabolizing blonanserin were investigated. Clearance of blonanserin by CYP3A4.4, 5, 7-10, 12-14, 16-18, 23-24, 28, 31, 33, and 34 decreased notably, but increased with CYP3A4.29. Additionally, we established a drug interaction spectrum for blonanserin, in which nimodipine, felodipine, and amlodipine kinetics exhibited mixed inhibition. Moreover, their inhibitory potencies decreased with CYP3A4.4 and 5 compared to CYP3A4.1. This study provides essential data for personalized clinical use of blonanserin.

Characterization of pharmacogenomic variants in a Brazilian admixed cohort of elderly individuals based on whole-genome sequencing data

Introduction: Research in the field of pharmacogenomics (PGx) aims to identify genetic variants that modulate response to drugs, through alterations in their pharmacokinetics (PK) or pharmacodynamics (PD). The distribution of PGx variants differs considerably among populations, and whole-genome sequencing (WGS) plays a major role as a comprehensive approach to detect both common and rare variants. This study evaluated the frequency of PGx markers in the context of the Brazilian population, using data from a population-based admixed cohort from Sao Paulo, Brazil, which includes variants from WGS of 1,171 unrelated, elderly individuals. Methods: The Stargazer tool was used to call star alleles and structural variants (SVs) from 38 pharmacogenes. Clinically relevant variants were investigated, and the predicted drug response phenotype was analyzed in combination with the medication record to assess individuals potentially at high-risk of gene-drug interaction. Results: In total, 352 unique star alleles or haplotypes were observed, of which 255 and 199 had a frequency < 0.05 and < 0.01, respectively. For star alleles with frequency > 5% (n = 97), decreased, loss-of-function and unknown function accounted for 13.4%, 8.2% and 27.8% of alleles or haplotypes, respectively. Structural variants (SVs) were identified in 35 genes for at least one individual, and occurred with frequencies >5% for CYP2D6, CYP2A6, GSTM1, and UGT2B17. Overall 98.0% of the individuals carried at least one high risk genotype-predicted phenotype in pharmacogenes with PharmGKB level of evidence 1A for drug interaction. The Electronic Health Record (EHR) Priority Result Notation and the cohort medication registry were combined to assess high-risk gene-drug interactions. In general, 42.0% of the cohort used at least one PharmGKB evidence level 1A drug, and 18.9% of individuals who used PharmGKB evidence level 1A drugs had a genotype-predicted phenotype of high-risk gene-drug interaction. Conclusion: This study described the applicability of next-generation sequencing (NGS) techniques for translating PGx variants into clinically relevant phenotypes on a large scale in the Brazilian population and explores the feasibility of systematic adoption of PGx testing in Brazil.

Polypharmacy and precision medicine

Precision medicine is an approach to maximise the effectiveness of disease treatment and prevention and minimise harm from medications by considering relevant demographic, clinical, genomic and environmental factors in making treatment decisions. Precision medicine is complex, even for decisions about single drugs for single diseases, as it requires expert consideration of multiple measurable factors that affect pharmacokinetics and pharmacodynamics, and many patient-specific variables. Given the increasing number of patients with multiple conditions and medications, there is a need to apply lessons learned from precision medicine in monotherapy and single disease management to optimise polypharmacy. However, precision medicine for optimisation of polypharmacy is particularly challenging because of the vast number of interacting factors that influence drug use and response. In this narrative review, we aim to provide and apply the latest research findings to achieve precision medicine in the context of polypharmacy. Specifically, this review aims to (1) summarise challenges in achieving precision medicine specific to polypharmacy; (2) synthesise the current approaches to precision medicine in polypharmacy; (3) provide a summary of the literature in the field of prediction of unknown drug-drug interactions (DDI) and (4) propose a novel approach to provide precision medicine for patients with polypharmacy. For our proposed model to be implemented in routine clinical practice, a comprehensive intervention bundle needs to be integrated into the electronic medical record using bioinformatic approaches on a wide range of data to predict the effects of polypharmacy regimens on an individual. In addition, clinicians need to be trained to interpret the results of data from sources including pharmacogenomic testing, DDI prediction and physiological-pharmacokinetic-pharmacodynamic modelling to inform their medication reviews. Future studies are needed to evaluate the efficacy of this model and to test generalisability so that it can be implemented at scale, aiming to improve outcomes in people with polypharmacy.

Genomics and multimorbidity

Multimorbidity has increased in prevalence world-wide. It is anticipated to affect over 1 in 6 of the UK population by 2035 and is now recognised as a global priority for health research. Genomic medicine has rapidly advanced over the last 20 years from the first sequencing of the human genome to integration into clinical care for rarer conditions. Genetic studies help identify new disease mechanisms as they are less susceptible to the bias and confounding that affects epidemiological studies, as genetics are assigned from conception. There is also genetic variation in the efficacy of medications and the risk of side effects, pharmacogenetics. Genomic approaches offer the potential to improve our understanding of mechanisms underpinning multiple long-term conditions/multimorbidity and guide precision approaches to risk, diagnosis and optimisation of management. In this commentary as part of the Age and Ageing 50th anniversary commentary series, we summarise genomics and the potential utility of genomics in multimorbidity.

Public perceptions of pharmacogenomic services in Ireland - Are people with chronic disease more likely to want service availability than those without? A questionnaire study

Background

As pharmacogenomic services begin to emerge in primary care, the insight of the public is crucial for its integration into clinical practice.

Objectives

To establish perceptions of pharmacogenomics (awareness, understanding, openness to availability, perceived benefits and concerns, willingness to pay, and service setting) and investigate if they differ between those with and without chronic disease(s).

Methods

An anonymous, online questionnaire generated using Qualtrics® and circulated via social media and posters placed in eight participating community pharmacies was conducted with Irish adults. The questions were designed to consider existing literature on patient perceptions of pharmacogenomics. Descriptive statistics were used to summarize questionnaire responses. Chi-square test was used to compare categorical variables, while independent sample t-test and one-way ANOVA were used to compare the mean values of two (with and without chronic disease) and three groups (multimorbidity (two or more chronic conditions) and polypharmacy (prescribed four or more regular medicines) (MMPP), a single chronic disease, and those without existing medical conditions) respectively Logistic regression was used to evaluate age and gender adjusted associations of chronic disease(s) with responses. A p-value <0.05 was considered statistically significant.

Results

A total of 421 responses were received, 30% (n = 120) of whom reported having a chronic disease. Overall, respondents reported low awareness (44%, n = 166) and poor knowledge (55%, n = 212) of pharmacogenomics. After explaining pharmacogenomics to respondents, patients with chronic disease(s) were 2.17 times more likely (p < 0.001) to want pharmacogenomic services availability than those without existing conditions, adjusted for age and gender (driven by preferences of those with MMPP than those with single chronic disease). Respondents demonstrated a high level of interest and noted both the potential benefits and downsides of pharmacogenomic testing. Willingness-to-pay was not associated with having a chronic disease and respondents were more positive about primary care (community pharmacy or general practice) rather than hospital-based pharmacogenomics implementation.

Conclusion

The Irish public in general and those with chronic disease in particular are strongly supportive of pharmacogenomic testing, highlighting an unmet need for its incorporation in medicines optimization. These data underline the need for more research on the implementation of community-based pharmacogenomics services for MMPP patients and ubiquitous pharmacogenomics education programs.

Pharmacists' Knowledge, and Insights in Implementing Pharmacogenomics in Saudi Arabia

BACKGROUND

Pharmacogenomics (PGx) and personalized medicine embrace the potential to optimize drug treatment and improve the patient's quality of life. Pharmacists' roles include contributing to genetic testing, patient counseling, and pharmacotherapies selection for superior treatment outcomes. The aim of this study is to assess the pharmacists' knowledge, insight, and self-confidence toward PGx testing, identify their future preferred education patterns, and determine the barriers to pharmacogenomic testing implementation.

METHOD

A cross-sectional study was conducted using a previously validated questionnaire among pharmacists working in the Kingdom of Saudi Arabia (KSA). The questionnaire was designed in seven major categories, consisting of 26 questions.

RESULTS

A total of 671 pharmacists participated in this survey. As for knowledge, only 29.8% of pharmacists had good knowledge regarding PGx, while 42.9% had poor knowledge levels. Respectable PGx knowledge was significantly higher among outpatient dispensing pharmacists (33.6%; p = 0.049) and among pharmacists who had completed PGx testing-related training or education (40.3%; p = 0.001). Considering perception, it was positive among 50% of pharmacists and negative among 19.8%. With regard to self-confidence, it was high among 39.2% of male pharmacists (p = 0.042), among 43% of clinical pharmacists (p = 0.006), and among 44.8% of pharmacists who had extra credentials (p = 0.001). The utmost favored continuing-education learning approaches were workshops or seminars. The barriers to the implementation of PGx testing included a lack of testing devices, clinical guidelines, training or education, and personnel.

CONCLUSION

The present study revealed that pharmacists in KSA had inadequate knowledge and understanding of PGx. Nevertheless, the majority established that PGx is a valuable tool for augmenting drug efficacy and safety.