The interface between pharmacoepidemiology and pharmacogenetics

Effect of Nifedipine Used in the Treatment of the Threat of Preterm Labor on Total Uterine Artery Blood Volume Flow Rate

PURPOSE

Evaluation of the effect of maternal nifedipine treatment on total uterine artery blood volume flow rate (TVFR).

METHODS

In this prospective study, 43 women who were admitted to the Perinatology Department of the University of Health Sciences Etlik Zübeyde Hanım Gynecology Training and Research Hospital, with the diagnosis of the threat of preterm labor, and 40 healthy pregnant women, who were randomly selected as the control group, were evaluated between July 1, 2018, and September 1, 2018. A transabdominal ultrasound examination of uterine arteries was performed both before and 48 hours after administration of oral nifedipine for TVFR measurement. For the final analysis, the TVFR levels of the group diagnosed with the threat of preterm labor and the control group were compared.

RESULTS

There was no significant difference in either uterine artery pulsatility index or resistance index values as well as the diameters of the uterine arteries after nifedipine treatment (p>0.05 for all). Total uterine artery blood volume flow rate (TVFR) was 424.66±236.74 mL/min before and 543.39±309.68 mL/min after treatment with nifedipine and was statistically significantly higher (p < 0.05).

CONCLUSIONS

Our study showed a statistically significant increase in total uterine artery blood volume flow rate 48 hours after oral nifedipine treatment.

Estimating heritability of glycaemic response to metformin using nationwide electronic health records and population-sized pedigree

Background

Variability of response to medication is a well-known phenomenon, determined by both environmental and genetic factors. Understanding the heritable component of the response to medication is of great interest but challenging due to several reasons, including small study cohorts and computational limitations.

Methods

Here, we study the heritability of variation in the glycaemic response to metformin, first-line therapeutic agent for type 2 diabetes (T2D), by leveraging 18 years of electronic health records (EHR) data from Israel’s largest healthcare service provider, consisting of over five million patients of diverse ethnicities and socio-economic background. Our cohort consists of 80,788 T2D patients treated with metformin, with an accumulated number of 1,611,591 HbA1C measurements and 4,581,097 metformin prescriptions. We estimate the explained variance of glycated hemoglobin (HbA1c%) reduction due to inheritance by constructing a six-generation population-size pedigree from national registries and linking it to medical health records.

Results

Using Linear Mixed Model-based framework, a common-practice method for heritability estimation, we calculate a heritability measure of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}^{2}=12.6 \%$$\end{document}h2=12.6% (95% CI, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$6.1 \%\! -\!19.1 \%$$\end{document}6.1%−19.1%) for absolute reduction of HbA1c% after metformin treatment in the entire cohort, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}^{2}=21.0 \%$$\end{document}h2=21.0% (95% CI, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$7.8 \%\! -\!34.4 \%$$\end{document}7.8%−34.4%) for males and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${h}^{2}=22.9 \%$$\end{document}h2=22.9% (95% CI, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10.0 \%\! -\!35.7 \%$$\end{document}10.0%−35.7%) in females. Results remain unchanged after adjusting for pre-treatment HbA1c%, and in proportional reduction of HbA1c%.

Conclusions

To the best of our knowledge, our work is the first to estimate heritability of drug response using solely EHR data combining a pedigree-based kinship matrix. We demonstrate that while response to metformin treatment has a heritable component, most of the variation is likely due to other factors, further motivating non-genetic analyses aimed at unraveling metformin’s action mechanism.

Individuals in a population might respond differently to the same medication and this phenomenon is commonly attributed to either genes or the environment. Here, we studied the familial aspects of the response to metformin, a medication used in the treatment of type 2 diabetes. We combined information from 18 years of medical records identifying newly treated patients with type 2 diabetes with information about how the trait was inherited within their families. We calculated a metric that tells us how well differences in people’s genes account for differences in their traits, and demonstrate that although the difference in response to metformin is in part explained by the genes people with type 2 diabetes inherit, most of it is not explained by genes. This finding contributes to a better understanding of differences in metformin response and might help inform treatment in future.

Kalka and Gavrieli et al. assessed the heritability of variation in the glycaemic response to metformin by leveraging electronic health records data gathered from a large cohort of patients with diabetes and combining it with pedigree information. The authors show that although the variability in this response has a heritable component, most of it is likely non-genetic.

Knowledge, attitude, future expectations and perceived barriers of medical students and physicians regarding pharmacogenomics in Jordan

BACKGROUND

Pharmacogenomics (PG) is a modern tool of personalising treatment protocols to improve the efficacy and safety of drug prescriptions. These benefits are offset by a slow uptake in clinical application due to a host of physician factors, patient factors and/or health system factors. Our study, thus, aimed to determine the knowledge, attitude, future expectations and perceived barriers of medical students and physicians in Jordan regarding PG testing.

METHODS

A descriptive, cross-sectional study was conducted between February and August 2019. Physicians and senior medical students from academic and non-academic institutions in North Jordan (n = 424) were surveyed. A structured, self-administered questionnaire was designed and piloted for the purpose of the study. A scoring system for each dimension assessed was calculated and presented using means. Mean scores were compared by sociodemographic and professional variables.

RESULTS

The response rate was 70.7%. The mean total PG knowledge score (±SD) was 5.42 (±1.51) out of 10, with a significantly higher mean among respondents aged <30 years (5.54 ± 1.43) compared with those ≥30 years old (5.21 ± 1.62; P = .03). The mean total PG attitude score was 21.18 (±2.58) out of 24, with significant differences by seniority levels evident (P = .03). The future expectations of PG among our sample were high, with a mean score of 10.44 (±1.64) out of 12. The top three perceived barriers in applying PG were the high cost, lack of clinical guidelines, and limited knowledge and awareness.

CONCLUSION

Physicians and medical students in Jordan have low overall knowledge, albeit strongly positive attitude and future expectations towards PG, despite the perceived high cost and lack of clinical guidelines. Thus, we strongly recommend adopting a comprehensive educational strategy that aims to integrate PG concepts into medical curricula, and promote the culture of continuous medical education about PG among practitioners.

How to Transition from Single-Gene Pharmacogenetic Testing to Preemptive Panel-Based Testing: A Tutorial

There have been significant advancements in precision medicine and approaches to medication selection based on pharmacogenetic results. With the availability of direct-to-consumer genetic testing and growing awareness of genetic interindividual variability, patient demand for more precise, individually tailored drug regimens is increasing. The University of Florida (UF) Health Precision Medicine Program (PMP) was established in 2011 to improve integration of genomic data into clinical practice. In the ensuing years, the UF Health PMP has successfully implemented several single-gene tests to optimize the precision of medication prescribing across a variety of clinical settings. Most recently, the UF Health PMP launched a custom-designed pharmacogenetic panel, including pharmacogenes relevant to supportive care medications commonly prescribed to patients undergoing chemotherapy treatment, referred to as "GatorPGx." This tutorial provides guidance and information to institutions on how to transition from the implementation of single-gene pharmacogenetic testing to a preemptive panel-based testing approach. Here, we demonstrate application of the preemptive panel in the setting of an adult solid tumor oncology clinic. Importantly, the information included herein can be applied to other clinical practice settings.

Pharmacogenetics and the treatment of functional gastrointestinal disorders

The diagnosis and management of functional gastrointestinal disorders (FGIDs) remain very challenging. In the era of precision medicine, it is important to individualize the treatment of these conditions by providing targeted and effective therapies while minimizing the risk of medication side effects. By using genetic information that predicts and affects the responses to specific medications, it is anticipated that the science of pharmacogenetics in FGIDs will advance the practice of precision medicine. The pathophysiology of FGIDs is complex, involving the interaction between predisposing genetic and environmental factors. Studies have shown that genetic polymorphisms may contribute to the variable responses to specific medications among individuals with FGIDs. Genetic variations in the CYP450 system can affect the metabolism and, hence, the pharmacokinetics of drugs used to treat FGIDs. Polymorphisms in the genes controlling proteins that are involved in the direct action of medications targeting the serotonergic, cannabinoid, adrenergic and bile acid pathways can affect the pharmacologic effects of the medications. In this review, we summarize the published literature on the pharmacogenetics of FGIDs and address the potential clinical utility and future challenges in this field. Since it was the dominant topic in the majority of the articles relevant to FGIDs, our review will focus on irritable bowel syndrome.

Whole-Genome Sequencing in Healthy People

Recent technological advances have radically changed genetic testing from an expensive and burdensome undertaking to a rapid and less costly option for many purposes. The utility of "next-generation" sequencing has been found to establish the diagnosis for hundreds of genetic disorders, to assess pharmacogenomic variants, and to identify treatable targets within malignant neoplasms. The ready availability of genomic information has led to the question of whether there would be clinical benefit of sequencing the genome of individuals who are not seeking a diagnosis, that is, genomic screening in generally healthy people, to provide anticipatory insights for their health care. Little research has been conducted in this area. We examine the considerable unresolved scientific and ethical issues encountered when considering whole-genome sequencing of healthy people.

RS11212617 is associated with metformin treatment response in type 2 diabetes in Shanghai local Chinese population

OBJECTIVE

This study was designed to examine the relevance of single-nucleotide polymorphism (SNP) rs11212617 with treatment success in type 2 diabetes patients from Shanghai local Chinese Han population.

METHODS

We genotyped rs11212617 in incident metformin users of type 2 diabetes patients from Shanghai local Chinese Han population. Association between rs11212617 and changes in HbA1c, fasting plasma glucose and postprandial glucose level were analysed.

RESULTS

Two hundred and seventy-four incident metformin users were included in the study sample. The SNP rs11212617 was significantly associated with metformin response in Shanghai local Chinese Han population.

CONCLUSION

The rs11212617 is associated with a reduction in HbA1c, fasting plasma glucose and postprandial glucose level. These results suggest that metformin treatment may be more efficacious in Shanghai and valuable for Chinese daily clinical practice.

Confronting the challenges of effective pain management in children following tonsillectomy

Tonsillectomy is an extremely common surgical procedure associated with significant morbidity and mortality. The post-operative challenges include: respiratory complications, post-tonsillectomy hemorrhage, nausea, vomiting and significant pain. The present model of care demands that most of these children are managed in an ambulatory setting. The recent Federal Drug Agency (FDA) warning contraindicating the use of codeine after tonsillectomy in children represents a significant change of practice for many pediatric otolaryngological surgeons. This introduces a number of other safety concerns when deciding on a safe alternative to codeine, especially since most tonsillectomy patients are managed by lay primary caregiver's at home. This review outlines the safety issues and proposes, based on currently available evidence, a preventative multi-modal strategy to manage pain, nausea and vomiting without increasing the risk of post-tonsillectomy bleeding.

Application of routine electronic health record databases for pharmacogenetic research

Inter-individual variability in drug responses is a common problem in pharmacotherapy. Several factors (non-genetic and genetic) influence drug responses in patients. When aiming to obtain an optimal benefit-risk ratio of medicines and with the emergence of genotyping technology, pharmacogenetic studies are important for providing recommendations on drug treatments. Advances in electronic healthcare information systems can contribute to increasing the quality and efficiency of such studies. This review describes the definition of pharmacogenetics, gene selection and study design for pharmacogenetic research. It also summarizes the potential of linking pharmacoepidemiology and pharmacogenetics (along with its strengths and limitations) and provides examples of pharmacogenetic studies utilizing electronic health record databases.

Genetics and pharmacogenomics in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is an uncommon disease in the general population, but a disease with significant morbidity and mortality. The prevalence of heritable PAH (HPAH) remains unknown. The reason for incomplete penetrance of HPAH is not well understood. A patient's clinical response to disease-specific therapy is complex, involving the severity of the patient's disease, other comorbidities, appropriateness of the prescribed therapy, and patient compliance. Warfarin is often used as an adjuvant therapy in patients with PAH.

Bioethics and the reinforcement of socio-technical expectations

Over the past few years, considerable interest has been paid to the way in which social expectations (hopes, hypes, fears) about new genomic technologies help shape, and in themselves are shaped by, emerging technologies, regulatory regimes and social concerns. In comparison, little attention has been paid to the role of expectations in related, but non-scientific discourses, such as bioethics. Drawing on a review of publications addressing the ethical issues associated with pharmacogenetics, this paper presents a detailed critique of bioethicists' contribution to these debates. The review highlights how, almost a decade after bioethical debate around pharmacogenetics started, and in contrast to the profession's self-perception as a form of regulator, bioethicists still largely restrict themselves to reviews of possible ethical issues raised by this technology, rather than critiquing others' positions and arguing for specific points of view. In addition the paper argues that bioethicists tend to: accept unquestioningly scientists' expectations about the development and ethical issues raised by pharmacogenetics; ignore contributions from bioethicists who do question these expectations; and engage in an ethical debate, the boundaries of which have been laid down and defined by academic and industry scientists. The paper concludes by offering some possible explanations for why the bioethical discourse has taken this form.

Recruitment of participants through community pharmacies for a pharmacogenetic study of antihypertensive drug treatment

OBJECTIVE

To describe the design, recruitment and baseline characteristics of participants in a community pharmacy based pharmacogenetic study of antihypertensive drug treatment.

SETTING

Participants enrolled from the population-based Pharmaco-Morbidity Record Linkage System.

METHOD

We designed a nested case-control study in which we will assess whether specific genetic polymorphisms modify the effect of antihypertensive drugs on the risk of myocardial infarction. In this study, cases (myocardial infarction) and controls were recruited through community pharmacies that participate in PHARMO. The PHARMO database comprises drug dispensing histories of about 2,000,000 subjects from a representative sample of Dutch community pharmacies linked to the national registrations of hospital discharges.

RESULTS

In total we selected 31010 patients (2777 cases and 28233 controls) from the PHARMO database, of whom 15973 (1871 cases, 14102 controls) were approached through their community pharmacy. Overall response rate was 36.3% (n = 5791, 794 cases, 4997 controls), whereas 32.1% (n = 5126, 701 cases, 4425 controls) gave informed consent to genotype their DNA. As expected, several cardiovascular risk factors such as smoking, body mass index, hypercholesterolemia, and diabetes mellitus were more common in cases than in controls.

CONCLUSION

Furthermore, cases more often used beta-blockers and calcium-antagonists, whereas controls more often used thiazide diuretics, ACE-inhibitors, and angiotensin-II receptor blockers. We have demonstrated that it is feasible to select patients from a coded database for a pharmacogenetic study and to approach them through community pharmacies, achieving reasonable response rates and without violating privacy rules.

Glutathione S-transferase M1 and T1 polymorphisms may predict adverse effects after therapy in children with medulloblastoma

Glutathione S-transferases (GSTs) are polymorphic enzymes that catalyze the glutathione conjugation of alkylating agents, platinum compounds, and free radicals formed by radiation used to treat medulloblastoma. We hypothesized that GST polymorphisms may be responsible, in part, for individual differences in toxicity and responses in pediatric medulloblastoma. We investigated the relationship between GSTM1 and GSTT1 polymorphisms and survival and toxicity in 42 children with medulloblastoma diagnosed and treated at the Texas Children's Cancer Center. We conducted Kaplan-Meier analyses to determine if the GST polymorphisms were related to progression-free survival (PFS) and performed logistic regression to explore associations between GST polymorphisms and occurrence of grade 3 or greater (> or =Gr 3) myelosuppression, ototoxicity, nephrotoxicity, neurotoxicity, and intellectual impairment. Patients with at least one null genotype had a 4.3 (95% confidence interval, 1.1-16.8), 3.7 (1-13.6), and 6.4 (1.2-34) times increased risk for any > or =Gr 3 toxicity, any > or =Gr 3 toxicity excluding peripheral neuropathy, and any > or =Gr 3 toxicity requiring omission or cessation of chemotherapy, respectively. Compared with all others, patients with at least one null genotype had, on average, 27.2 (p x= 0.0002), 29 (p = 0.0004), and 21.7 (p = 0.002) lower full-scale, performance, and verbal intelligence quotient (IQ) scores, respectively. GSTM1 and GSTT1 polymorphisms may predict adverse events, including cognitive impairment after therapy, in patients with medulloblastoma. A larger study to validate these findings is under way.

Pharmacogenetics of glucose-lowering drug treatment: a systematic review

Intensive blood glucose lowering can significantly reduce the risk of micro- and macrovascular complications in patients with diabetes mellitus. However, 30% of all treated patients do not achieve optimal blood glucose levels. Genetic factors may influence the response to glucose-lowering medication. A search of MEDLINE-indexed literature published between January 1966 and July 2007 revealed 37 studies reporting data on genetic polymorphisms and response to glucose-lowering drugs. Most studies involving cytochrome P450 (CYP) genes had small sample sizes (21 studies <50 subjects) and were among healthy volunteers. Multiple studies indicated that the CYP2C9 *3 allele (Ile359Leu polymorphism) was associated with decreased clearance of sulfonylurea drugs. Supporting this, one study reported an increased insulin secretion in CYP2C9*3 allele carriers when using the sulfonylurea agent glyburide. The CYP2C9*3 allele was also associated with a decreased clearance of meglitinides, whereas the CYP2C8*3 (Arg139Lys; Lys399Arg) variant increased the clearance of meglitinides. Polymorphisms in genes encoding the inwardly rectifying potassium channel Kir6.2 (KCNJ11) and the insulin receptor substrate-1 (IRS1) were reported to be associated with an increased risk of (secondary) failure to respond to sulfonylurea therapy. A significant decrease in fasting plasma glucose and hemoglobin A(1c) (HbA(1c)) in response to rosiglitazone was seen in subjects carrying the Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma (PPARG) gene. Conversely, carriers of this polymorphism also had a higher conversion to diabetes mellitus when treated with acarbose; this effect was also seen in adiponectin (ADIPOQ) gene polymorphism carriers. Future studies with adequate sample sizes in which several SNPs in multiple candidate genes are genotyped in patients with diabetes should provide reliable information on genetic variants and response to glucose-lowering drugs.

Folate pathway genetic polymorphisms are related to attention disorders in childhood leukemia survivors

OBJECTIVE

To test the hypothesis that 5,10-methylenetetrahydroreductase (MTHFR) polymorphisms can partially explain the individual variation in developing attention-deficit/hyperactivity disorder (ADHD) after acute lymphoblastic leukemia (ALL) therapy.

STUDY DESIGN

Parents of 48 survivors of childhood ALL completed a clinical diagnostic process to identify subtypes of ADHD. Genotyping was performed with peripheral blood DNA for MTHFR (C677T and A1298C) polymorphisms.

RESULTS

Eleven of the 48 patients (22.9%) had scores consistent with the inattentive symptoms of ADHD. Patients with genotypes related to lower folate levels (11 out of 39; 39.2%) were more likely to have ADHD. The A1298C genotype appeared to be the predominant linkage to the inattentive symptoms, leading to a 7.4-fold increase in diagnosis, compared with a 1.3-fold increase for the C677T genotype. Age at diagnosis and sex were not associated with inattentiveness.

CONCLUSIONS

Preliminary data imply a strong relationship between MTHFR polymorphisms and the inattentive symptoms of ADHD in survivors of childhood ALL.

[Drug interchangeability: clinical approach and consumer's point of view]

The rational construction of an essential drug list, considering the patient's need, drug safety, availability and the best cost-benefit ratio, is based on drug safety, efficacy and quality. However, in daily practice, the prescriber's decision is mostly influenced by drug effectiveness, following criteria that increase adherence to the treatment, such as relative drug toxicity, convenience, cost and prescriber's experience. In addition, frequent launching of new molecules for the same therapeutic indication, together with wide publicity targeting prescribers, interferes with the decision-making process. Similarly, the bonuses offered by the industry for over-the-counter drug sales interfere with the consumer's choice. The confrontation between known human biological variability and the knowledge that there is no absolute similarity between drugs of the same therapeutic class, or even generic drugs, has an impact on the prescriber's drug list, which should include the concept of first and second choice drugs. Prescribers' unfamiliarity with these subjects is a determinant factor for irrational drug use: a public health issue. The objective of this study was to introduce to drug prescribers information that can help them building up a rational drug list for their patients, based on the National Health Surveillance Agency (Anvisa) experience of drug regulation.

Linking laboratory and medication data: new opportunities for pharmacoepidemiological research

Transfer of automated laboratory data collected during routine clinical care from the laboratory information system into a database format that enables linkage to other administrative (e.g., patient characteristics) or clinical (e.g., medication, diagnoses, procedures) data provides a valuable tool for clinical epidemiological research. It allows the investigation of biochemical characteristics of diseases, therapeutic effects and diagnostic and/or prognostic markers for disease with easy access and at relatively low cost. To this end, the Utrecht Patient Oriented Database (UPOD), an infrastructure of relational databases comprising data on patient characteristics, laboratory test results, medication orders, hospital discharge diagnoses and medical procedures for all patients treated at the University Medical Centre Utrecht since January 2004, was established. Current research within UPOD is focused on the innovative linkage of laboratory and medication data, which, for example, makes it possible to assess the quality of pharmacotherapy in clinical practice, to investigate interference between laboratory tests and drugs, to study the risk of adverse drug reactions, and to develop diagnostic and prognostic markers or algorithms for adverse drug reactions. Although recently established, we believe that UPOD broadens the opportunities for clinical pharmacoepidemiological research and can contribute to patient care from a laboratory perspective.

Genetic epidemiology of acute respiratory distress syndrome: implications for future prevention and treatment

The genetic susceptibility to the development of and variable outcomes in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) has become a topic of great interest in the pulmonary and critical care community. Published studies of variable genetic susceptibility to ALI/ARDS already have identified some important candidate genes and potential gene-environment interactions. This article reviews these recent studies, features of the current approach, and implications for future prevention and treatment in ALI. The challenges and potential contributions of genetic epidemiology to the future prevention and treatment in ALI are discussed.

Pharmaceutical care in community pharmacy: practice and research in the Netherlands

OBJECTIVE

To describe the pharmaceutical care activities and research in community pharmacy in the Netherlands.

FINDINGS

Pharmaceutical care is well advanced in Dutch pharmacy practice. This is largely due to the fact that clinical pharmacy was already an integrated part of community pharmacy practice by the end of the 1980s. Activities of the International Pharmaceutical Federation (FIP), some wholesale companies, and influential individuals in the Netherlands stimulated universities and the Royal Society for the Advancement of Pharmacy to advance the implementation of pharmaceutical care.

DISCUSSION

Not all pharmacies in the Netherlands provide pharmaceutical care at the same level, although medication surveillance (concurrent and prospective medication analysis) is part of everyday practice. Implementation of quality assurance systems in community pharmacy practice could be helpful in assuring high levels of care. Similar to those in other countries, Dutch pharmacists are torn between the wish to provide pharmaceutical care and economic considerations, although the financial status of most pharmacies is still (very) healthy. New entrants into the market, such as supermarket and pharmacy chains, seem to put little emphasis on care provision.

CONCLUSIONS

Pharmaceutical care has been implemented in many Dutch community pharmacies, but not everywhere to the same extent. Due to excellent automated medication surveillance; structured, high-quality medication counseling; and the fact that patients usually visit the same pharmacy, Dutch patients are well protected against many drug-related problems.

A review on the design and reporting of studies on drug–gene interaction

OBJECTIVE

Methodological standards for clinical pharmacogenetic studies should be developed to improve reporting of studies and facilitate their inclusion in systematic reviews. The essence of these studies lies within the concept of effect modification.

STUDY DESIGN AND SETTING

A narrative review discussing methodological issues in the design and reporting of pharmacogenetic studies.

RESULTS

Studying effect modification within a trial leads to the comparison of subgroups based on genotype. Differences in effect based on genotype should preferably be expressed in absolute terms (risk differences) to facilitate clinical decisions on treatment. Information on the distribution of potential effect modifiers or prognostic factors should be available to prevent a biased comparison of differences in effect between genotypes. The distribution of genotypes should also be presented and compared to Hardy-Weinberg equilibrium to check for selection bias. Additional points of interest include the possibility of selective nonavailability of biomaterial and the choice of a statistical model to study effect modification.

CONCLUSION

Additional methodological issues should be taken into account when designing and reporting pharmacogenetic studies, to ensure high study quality. We present several important issues for future studies investigating drug-gene interactions that can serve as a basis for further discussion on methodology in pharmacogenetics.

The genesis of neurosurgery and the evolution of the neurosurgical operative environment: part II--concepts for future development, 2003 and beyond

The future development of the neurosurgical operative environment is driven principally by concurrent development in science and technology. In the new millennium, these developments are taking on a Jules Verne quality, with the ability to construct and manipulate the human organism and its surroundings at the level of atoms and molecules seemingly at hand. Thus, an examination of currents in technology advancement from the neurosurgical perspective can provide insight into the evolution of the neurosurgical operative environment. In the future, the optimal design solution for the operative environment requirements of specialized neurosurgery may take the form of composites of venues that are currently mutually distinct. Advances in microfabrication technology and laser optical manipulators are expanding the scope and role of robotics, with novel opportunities for bionic integration. Assimilation of biosensor technology into the operative environment promises to provide neurosurgeons of the future with a vastly expanded set of physiological data, which will require concurrent simplification and optimization of analysis and presentation schemes to facilitate practical usefulness. Nanotechnology derivatives are shattering the maximum limits of resolution and magnification allowed by conventional microscopes. Furthermore, quantum computing and molecular electronics promise to greatly enhance computational power, allowing the emerging reality of simulation and virtual neurosurgery for rehearsal and training purposes. Progressive minimalism is evident throughout, leading ultimately to a paradigm shift as the nanoscale is approached. At the interface between the old and new technological paradigms, issues related to integration may dictate the ultimate emergence of the products of the new paradigm. Once initiated, however, history suggests that the process of change will proceed rapidly and dramatically, with the ultimate neurosurgical operative environment of the future being far more complex in functional capacity but strikingly simple in apparent form.

Changes in prescribed drug doses after market introduction

PURPOSE

The establishment of recommended dosing regimens has always been a difficult aspect of drug development. This paper examines the extent to which postmarketing prescribing deviates from initially recommended dosing regimens. We used the World Health Organization's (WHO) periodically updated compilation of the 'Defined Daily Dose' (DDD) to reflect prevailing patterns of prescribing in national markets. The aim of this study was to evaluate DDD changes over time (1982-2000) and to identify possible determinants of these changes.

METHODS

Data on DDD changes were obtained from the WHO's Oslo Collaborating Centre. We performed a case-control analysis in which we compared drugs with (cases) and without (controls) postmarketing changes in DDD on possible determinants associated with DDD change.

RESULTS

We found 115 instances of a change of DDD in the period 1982-2000 (45 (39.1%) increases and 70 (60.9%) decreases). Antibiotics showed the greatest number of changes in DDD: predominantly increases in the 1980s, while the 1990s were dominated by decreases in DDD of mostly cardiovascular drugs.

CONCLUSION

Changes in DDD reflect the outcome of a melange of forces, including misconceptions of dose requirements during pre-market development of drug and postmarketing changes in pharmacotherapeutic knowledge, clinical concepts, economic forces, and, in the case of anti-infective agents, changing patterns of resistance/sensitivity of target microorganisms to the anti-infective agent(s) in question.

Genetic polymorphisms: importance for response to HMG-CoA reductase inhibitors

Coronary artery disease is among the leading causes of death worldwide. Clinical trials show a protective effect of statins against the sequelae of coronary artery disease. The mean risk reductions for subjects using statins compared with placebo found in these trials is about 30%. These are average reductions for all patients included in the trials. Important factors in interpreting the variability in the outcome of drug therapy include the patient's health profile, prognosis, disease severity, quality of drug prescribing, compliance with prescribed pharmacotherapy and the genetic profile of the patient. This review aims to give an overview of the known polymorphisms (Cholesteryl Ester Transfer Protein polymorphism, Stromelysin-1 polymorphism, -455G/A and TaqI polymorphisms of the beta-fibrinogen gene, apoE4, Asp(9)Asn mutation in the lipoprotein lipase gene, the -514 CT polymorphism in the hepatic lipase gene and the ACE deletion type gene) that have an influence on the effects of statins in the general population. The expectation is that in the future a subject's genotype may determine whether he will be treated with statins or not. Determining the genotype will not deny therapy to a subject, but will help in deciding the therapy that will suit the patient best.

2001: Things to come

THIS ARTICLE DISCUSSES elements in the definition of modernity and emerging futurism in neurological surgery. In particular, it describes evolution, discovery, and paradigm shifts in the field and forces responsible for their realization. It analyzes the cyclical reinvention of the discipline experienced during the past generation and attempts to identify apertures to the near and more remote future. Subsequently, it focuses on forces and discovery in computational science, imaging, molecular science, biomedical engineering, and information processing as they relate to the theme of minimalism that is evident in the field. These areas are explained in the light of future possibilities offered by the emerging field of nanotechnology with molecular engineering.