Application of the Bradford Hill Criteria to Assess the Causality of Cisapride-Induced Arrhythmia

Ocular adverse events associated with platins: a disproportionality analysis of pharmacovigilance data and extensive systematic review of case reports

BACKGROUND

Anti-cancer drugs, particularly platinum-based chemotherapy drugs, have been showing ocular adverse events (OAEs) in patients undergoing chemotherapy, which is concerning due to the potential impact on patient's quality of life and the ability to continue effective cancer treatment.

RESEARCH DESIGN AND METHODS

A retrospective case/non-case study was conducted using spontaneous reports on OAEs by platins from the FDA Adverse Event Reporting System (FAERS) database. A disproportionality analysis was performed by calculating the Proportional Reporting Ratio (PRR), Reporting Odds Ratio (ROR), and the Information Component (IC) to identify OAE signals for platinum-based chemotherapy drugs. In parallel, a review of case reports for OAEs from platins was conducted by a systematic literature search in PubMed and Google Scholar.

RESULTS

Using disproportionality analysis, 69 signals were identified for platinum-based chemotherapy drugs and OAEs (carboplatin: 42, oxaliplatin: 16, cisplatin: 11). Choroidal infarction [PRR = 215.1; χ2 = 4527.1; lower bound (LB) ROR = 140.7; IC025 = 5.1] and orbital hemorrhage [PRR = 120.0; χ2 = 300.5; LB ROR = 35.1; IC025 = 1.3] were the strong signals identified for carboplatin. Optic disc hyperemia [PRR = 208.2; χ2 = 742.5; LB ROR = 74.1; IC025 = 2.2] and blindness cortical [PRR = 23.7; χ2 = 382.5; LB ROR = 14.8; IC025 = 3.1] were the signals identified for oxaliplatin and cisplatin, respectively. A total of 32 case reports of OAEs from platinum-based chemotherapy drugs were identified through a systematic search in PubMed and Google Scholar, strengthening the association.

CONCLUSION

The study revealed a potential risk of OAEs when using platinum-based chemotherapy drugs as an anticancer medication.

The REporting of A Disproportionality Analysis for DrUg Safety Signal Detection Using Individual Case Safety Reports in PharmacoVigilance (READUS-PV): Explanation and Elaboration

In pharmacovigilance, disproportionality analyses based on individual case safety reports are widely used to detect safety signals. Unfortunately, publishing disproportionality analyses lacks specific guidelines, often leading to incomplete and ambiguous reporting, and carries the risk of incorrect conclusions when data are not placed in the correct context. The REporting of A Disproportionality analysis for drUg Safety signal detection using individual case safety reports in PharmacoVigilance (READUS-PV) statement was developed to address this issue by promoting transparent and comprehensive reporting of disproportionality studies. While the statement paper explains in greater detail the procedure followed to develop these guidelines, with this explanation paper we present the 14 items retained for READUS-PV guidelines, together with an in-depth explanation of their rationale and bullet points to illustrate their practical implementation. Our primary objective is to foster the adoption of the READUS-PV guidelines among authors, editors, peer reviewers, and readers of disproportionality analyses. Enhancing transparency, completeness, and accuracy of reporting, as well as proper interpretation of their results, READUS-PV guidelines will ultimately facilitate evidence-based decision making in pharmacovigilance.

Important Considerations for Signal Detection and Evaluation

Safety clinicians have a wealth of resources describing how to perform signal detection. Nevertheless, there are some nuances concerning approaches taken by regulatory authorities and statistical considerations that should be appreciated. New approaches, such as the FDA Medical Queries, illustrate the value of considering medical concepts over individual adverse events. One area which would benefit from further clarity is how safety signals may be evaluated for evidence of a causal relationship to the drug of interest. Just as such safety signals can take many forms, the types of tools and methods required to interrogate these signals are equally as diverse. An understanding of the complexity of this process can aid the safety reviewer in successfully characterizing the emerging safety profile of a drug during the pre-marketing phase of development.

Signals of Adverse Drug Reactions Communicated by Pharmacovigilance Stakeholders: A Scoping Review of the Global Literature

INTRODUCTION AND OBJECTIVE

Signals of adverse drug reactions (ADRs) can be supported by reports of ADRs and by interventional and non-interventional studies. The evidence base and features of ADR reports that are used to support signals remain to be comprehensively described. To this end, we have undertaken a scoping review.

METHODS

We searched the following databases: PubMed, EMBASE, PsycINFO, Web of Science, and Google Scholar, without language or time restrictions. We also hand searched the bibliographies of relevant studies. We included studies of any design if the results were described as signals. We assessed the levels of evidence using the Oxford Centre for Evidence-Based Medicine (OCEBM) criteria and coded features of reports of ADRs using the Bradford Hill guidelines.

RESULTS

Overall, 1974 publications reported 2421 studies of signals; 1683/2421 were clinical assessments of anecdotal reports of ADRs, but only 225 (13%) of these included explicit judgments on which features of the ADR reports were supportive of a signal. These 225 studies yielded 228 signals; these were supported by features, which were: 'experimental evidence' (i.e., positive dechallenge or rechallenge, 154 instances [68%]), 'temporality' (i.e., time to onset, 130 [57%]), 'exclusion of competing causes' (49 [21%]), and others (40 [17%]). Positive dechallenge/rechallenge often co-occurred with temporality (77/228). OCEBM 4 (i.e., case series and case-control studies) was the most frequent level of evidence (2078 studies). Between 2013 and 2019, there was a three-fold increase in clinical assessments of reports of ADRs compared with a less than two-fold increase in studies supported by higher levels of evidence (i.e., OCEBM 1-3). We identified an increased rate between 2013 and 2019 in disproportionality analyses (about 15 studies per year), mostly from academia.

CONCLUSIONS

Most signals were supported by temporality and dechallenge/rechallenge, but clear reporting of judgments on causality remains infrequent. The number of studies supported only by anecdotal reports of ADRs increased from year to year. The impact of a growing number of signals of disproportionate reporting communicated without an accompanying clinical assessment should be evaluated.

c4c: Paediatric pharmacovigilance: Methodological considerations in research and development of medicines for children - A c4c expert group white paper

Children frequently respond differently to therapies compared to adults. Differences also exist between paediatric age groups for pharmacokinetics and pharmacodynamics in both efficacy and safety. Paediatric pharmacovigilance requires an understanding of the unique aspects of children with regard to, for example, drug response, growth and development, clinical presentation of adverse drug reactions (ADRs), how they can be detected and population-specific factors (e.g., more frequent use of off-label/unlicensed drugs). In recognition of these challenges, a group of experts has been formed in the context of the conect4children (c4c) project to support paediatric drug development. This expert group collaborated to develop methodological considerations for paediatric drug safety and pharmacovigilance throughout the life-cycle of medicinal products which are described in this article. These considerations include practical points to consider for the development of the paediatric section of the risk management plan (RMP), safety in paediatric protocol development, safety data collection and analysis. Furthermore, they describe the specific details of post-marketing pharmacovigilance in children using, for example, spontaneous reports, electronic health care records, registries and record-linkage, as well as the use of paediatric pharmacoepidemiology studies for risk characterisation. Next the details of the assessment of benefit-risk and challenges related to medicinal product formulation in the context of a Paediatric Investigation Plan (PIP) are presented. Finally, practical issues in paediatric signal detection and evaluation are included. This paper provides practical points to consider for paediatric pharmacovigilance throughout the life-cycle of medicinal products for RMPs, protocol development, safety data collection and analysis and PIPs.

Indapamide-Induced Rhabdomyolysis: An Evaluation of Case Reports in VigiBase Using the Bradford Hill Criteria

BACKGROUND

Indapamide can cause hypokalaemia and hyponatraemia. Rhabdomyolysis associated with these electrolyte abnormalities has been reported.

OBJECTIVE

The aim of this study was to assess causal association between the use of indapamide and the occurrence of rhabdomyolysis using the Bradford Hill criteria.

METHODS

Variables in the rhabdomyolysis case reports and literature were reviewed. Bradford Hill criteria were used in the assessment of causal association.

RESULTS

Up to 11 November 2020, there were 28 unique cases in VigiBase from 13 countries reporting indapamide-associated rhabdomyolysis. In 18 of these cases, hypokalaemia (n = 14) or hyponatremia (n = 8) was a co-reported event, including four cases where both of these events were reported. Indapamide was the only suspected drug in nine of these 18 cases and positive dechallenge was mentioned in 13 of them. In addition, there were risk factors such as falls, concomitant drugs with risk of hypokalaemia, or muscle injury. In two cases, liquorice (containing glycyrrhizin) was concomitantly used with indapamide before hypokalaemia and rhabdomyolysis occurred. Thiazide diuretics, known to cause hypokalaemia, showed similar disproportionality patterns as indapamide regarding rhabdomyolysis and myopathy, while calcium channel blockers (not causing hypokalaemia), had lower disproportionality values than indapamide.

CONCLUSIONS

Based on the review of case series and causality assessment using Bradford Hill criteria, indapamide may cause rhabdomyolysis due to hypokalaemia or hyponatremia. Considering the seriousness of the reported cases, health care professionals should be aware of this potential risk following indapamide intake, particularly when there are risk factors for hypokalaemia and hyponatremia such as excessive liquorice consumption. A similar risk of muscle injuries may apply to thiazide diuretics as well.

Maternal paracetamol intake and fetal ductus arteriosus constriction/closure: comprehensive signal evaluation using the Austin Bradford Hill criteria

PURPOSE

Acetaminophen (APAP) is available over-the-counter and widely regarded as safe for use in pregnancy. APAP has been used to close a persistently patent ductus arteriosus. Fetal constriction/closure of the ductus arteriosus (FCCDA), of public health interest given the drug's widespread use during pregnancy, is being monitored globally, including by the European Medicines Agency Pharmacovigilance Risk Assessment Committee. Our objective was to share a comprehensive signal evaluation of FCCDA with in utero APAP exposure to determine if the totality of evidence is sufficiently more consistent with one of the following two possibilities: (1) APAP never contributes to FCCDA (null hypothesis or H_O) versus (2) APAP may in some cases be at least a contributory cause of in utero DA narrowing (alternative hypothesis or H_A) to justify risk communication.

METHODS

To assess the relative support for H_O versus H_A, we synthesize and interpret within an Austin Bradford Hill criteria framework a comprehensive, cross-disciplinary set of published information and de novo analysis, including toxicology, epidemiology, clinical pharmacology, and clinical and quantitative pharmacovigilance analysis of spontaneous reports.

RESULTS

While residual uncertainty remains, the totality of information is more compatible with H_A than H₀, to the extent that it is reasonably possible that APAP may sometimes be at least a contributory cause of FCCDA.

CONCLUSION

It is reasonably possible that APAP may sometimes be at least a contributory cause of FCCDA, and this should therefore be communicated to stakeholders.

TRIAL REGISTRATION

CLINICALTRIALS.

GOV REGISTRATION

NOT APPLICABLE.

Tumor necrosis factor inhibitor-induced pleuropericarditis: A retrospective evaluation using data from VigiBase

OBJECTIVE

The aim of this study was to assess the causality of anti-TNFα agents-associated pleuropericarditis in VigiBase with a focus on its diverse types.

METHODS

All variables contained in the pleuropericarditis reports were reviewed. Well-documented reports, vigiGrade completeness score ≥ 0.80 or with an informative narrative, were analyzed and with a focus on the clinical features of the cases. Bradford-Hill criteria were used in the case series assessment of causality.

RESULTS

From 1968 up to 18 December 2019, there were 94 unique cases from 18 countries reporting pleuropericarditis with anti-TNFα agents as a suspected or interacting medicine. Among the 94 reports, 42 were identified as well-documented and further assessed for clinical features. Of the 42 cases, 39 were serious, including three fatal and seven life-threatening. In 35 cases, an anti-TNFα agent was the only suspected drug. Positive de- and re-challenge were reported in 95% and 17% of the 42 cases, respectively. The times to onset (TTO) varied greatly among individual cases, ranging from one month to 75 months (mean = 24 months). The most commonly involved anti-TNFα agents were adalimumab, infliximab and etanercept; and the mostly reported pleuropericarditis types were classified as autoimmune-related with (n = 17) or without (n = 15) co-reported drug-induced lupus (DIL), or infection-related (n = 8). While adalimumab was the most reported in the infection-related cases (7/8), infliximab was the most frequent in the autoimmune-related cases, in particular co-reported with DIL (9/17). There were four cases where the reaction occurred one to two months after the anti-TNFα agents (infliximab and adalimumab) were stopped. Based on the review of the case series using Bradford-Hill criteria the anti-TNFα agents associated pleuropericarditis are considered as a class effect.

CONCLUSIONS

To clinically recognize and manage these potentially life-threatening serious cardiopulmonary complications, health care professionals should be aware of this possible risk. Meanwhile, attention should be paid to the clinical features of pleuropericarditis cases, since they may cause diagnostic and therapeutic difficulties. Considering the long elimination time, clinicians need to be reminded to remain vigilant for the adverse reactions even after discontinuing anti-TNFα therapy.

Nintedanib and ischemic colitis: Signal assessment with the integrated use of two types of real-world evidence, spontaneous reports of suspected adverse drug reactions, and observational data from large health-care databases

Purpose

Statistical screening of Vigibase, the global database of individual case safety reports, highlighted an association between the MedDRA Preferred Term (PT) “colitis” and nintedanib. Nintedanib is a protein kinase inhibitor authorized in accelerated regulatory procedures for the treatment of idiopathic pulmonary fibrosis (IPF). The aim of this report is to describe the integration of two types of real‐world evidence, spontaneous reports of adverse drug reactions (ADR), and observational health data (OHD) in the assessment of a post‐authorization safety signal of ischemic colitis.

Methods

Assessment of the statistical signal of “nintedanib – colitis” was undertaken using data from VigiBase, OHD from the Observational Heath Data Sciences and Informatics (OHDSI) collaborative, published literature, and openly available regulatory documents. Evidence synthesis was performed to support Bradford Hill criteria in causality assessment.

Results

Evidence for strength of association, specificity, consistency, and analogy was found upon review of the case series. OHD was used to calculate incidence rates of colitis in new users of nintedanib across multiple populations, supportive of consistency, and further evidence for strength of association. Literature review identified support for biological plausibility and analogy. Signal assessment was supplemented with characterization of real‐world users and exploration of potential risk factors using OHD.

Conclusions

An integrated approach using two forms of real‐world data, spontaneous reports of ADRs and data from observational databases allowed a comprehensive and efficient signal assessment of nintedanib and colitis. Further exploration of the complementary use of real‐time OHD in signal assessment could inform more efficient approaches to current signal management practices.

Reviewing the Mechanistic Evidence Assessors E-Synthesis and EBM+: A Case Study of Amoxicillin and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)

Background:

Basic science has delivered unprecedented insights into intricate relationships on the smallest scales within well-controlled environments. Addressing pressing societal decision problems requires an understanding of systems on larger scales in real-world situations.

Objective:

To assess how well the evidence assessors E-Synthesis and EBM+ assess basic science findings to support medical decision making.

Method:

We demonstrate the workings of E-Synthesis and EBM+ on a case study: the suspected causal connection between the widely-used drug amoxicillin (AMX) and the putative adverse drug reaction: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS).

Results:

We determine an increase in the probability that AMX can cause DRESS within the E-Synthesis approach and using the EBM+ standards assess the basic science findings as supporting the existence of a mechanism linking AMX and DRESS.

Conclusions:

While progress is made towards developing methodologies which allow the incorporation of basic science research in the decision making process for pressing societal questions, there is still considerable need for further developments. A continued dialogue between basic science researchers and methodologists, philosophers and statisticians seems to offer the best prospects for developing and evaluating continuously evolving methodologies.

Efficacy of Capsaicin for the Treatment of Cannabinoid Hyperemesis Syndrome: A Systematic Review

Objective: Cannabinoid hyperemesis syndrome (CHS) is characterized by cyclic vomiting, abdominal pain, and alleviation of symptoms via hot showers in chronic cannabinoid users. Capsaicin is recommended as a reasonable first-line treatment approach for CHS despite limited clinical evidence regarding its use. The objective of this study is to systematically review the efficacy data for capsaicin in CHS. Data Sources: A literature search using keywords related to cannabinoids, emesis, and capsaicin was performed in MEDLINE, CINAHL, and EMBASE from inception through March 31, 2019. Study Selection and Data Extraction: Studies and published abstracts in which capsaicin was used for CHS and clinical outcomes were reported were eligible for inclusion. Data Synthesis: A total of 241 articles were screened, of which 5 full-text articles and 6 conference abstracts were included. Full-text case reports (n = 3) and case series (n = 2) found capsaicin to be effective in a total of 18 patients. Published abstracts were in the form of case reports (n = 1), case series (n = 3), and retrospective cohort studies (n = 2). Relevance to Patient Care and Clinical Practice: Capsaicin use was described as beneficial in all case series and case reports; however, both retrospective cohort studies were unable to find a significant benefit for capsaicin on primary outcomes (emergency department length of stay). Conclusion: Current data for capsaicin efficacy in CHS is of low methodological quality. However, the limited data on alternative antiemetic therapies and capsaicin’s favorable risk-benefit profile make it a reasonable adjunctive treatment option.

The spurious relationship between ecstasy use and neurocognitive deficits: A Bradford Hill review

Numerous studies have suggested that MDMA can cause neurocognitive deficits. However, the available data can only suggest an association - rather than a causal relationship - between MDMA use and neurocognitive deficits. The reliability and robustness of this association was evaluated using Bradford Hill's criteria for determining causation in epidemiology research. Several limitations in the literature were found. Studies have recruited people who abuse ecstasy - an illicit drug that does not always contain MDMA. There is inherent risk in consuming impure or falsely identified substances; and using this as a source as for scientific opinion may introduce biases in our understanding the actuals risks associated with MDMA. Importantly, given that ecstasy research is predominately retrospective, baseline functioning cannot be established; which may be influenced by a variety of preexisting factors. Many studies introduce statistical errors by inconsistently dichotomizing and comparing light and heavy ecstasy users, making dose-response relationships inconclusive. When interpreting the ecstasy literature effect sizes are a more meaningful indicator of neurocognitive functioning rather than relying on p-values alone. Most meta-analyses have failed to find clinically relevant differences between ecstasy users and controls. There is also consistent evidence of publication bias in this field of research, which indicates that the literature is both biased and incomplete. Finally, suggestions for improving the ecstasy literature are provided.

[Regulatory science in public health: What are we talking about?]

This article sheds light on a concept little known to public health actors in France: regulatory science, used to describe the range of scientific activities used to produce the knowledge mobilized to support, develop or adapt public policy decisions. The objective is to understand how the expression appeared in the mid-1980s and was formalized into a sociological concept by the American writer Sheila Jasanoff in 1990, and has gradually imposed itself in American, Japanese and European regulatory agencies as a new scientific discipline. The article examines the evolution of the concept and the various approaches proposed to define regulatory science. It highlights its hybrid and heterogeneous nature, underlining the different characteristics that the expression covers according to the institution which formulates it (FDA, EMA, PMDA) and the scope of application that it covers. Based on concrete examples of the application of regulatory science practices in three broad areas of health risk, the paper focuses on the role of research in the decision-making process by showing how the emergence of new methods designed to strengthen the regulatory capacities of regulators and the role of academic communities associated with this approach, contribute to the strengthening of public health policies in France and worldwide.

Adverse Drug Event Causality Analysis (ADECA): A Process for Evaluating Evidence and Assigning Drugs to Risk Categories for Sudden Death

Growing evidence indicates that many drugs have the ability to cause a potentially lethal cardiac arrhythmia, torsades de pointes (TdP). This necessitates the development of a compilation of drugs that have this potential toxicity. Such a list is helpful in identifying the etiology of TdP in patients taking multiple drugs and assists decision making by those caring for patients at high risk of TdP. The Arizona Center for Education and Research on Therapeutics (AZCERT) has developed a process to standardize the identification of drugs and place them in risk categories for their clinical ability to cause TdP and QT prolongation. AZCERT's Adverse Drug Event Causality Analysis (ADECA) utilizes 16 types of data drawn from four sources to compile an open-source knowledge base, QTdrugs, which is maintained on the CredibleMeds.org website. Because the evidence for most drugs is incomplete, the ADECA process is used to place drugs into one of three categories that represent different levels of certainty: known TdP risk, possible TdP risk, and conditional TdP risk. Each category has strict evidentiary requirements for clinical evidence of TdP and/or QT prolongation. These are described in this paper. Because evidence can evolve over time, the ADECA process includes the continuous gathering and analysis of newly emerging evidence to revise the lists. The QTdrugs lists have proven to be a valued, readily available, commercial influence-free resource for healthcare providers, patients, researchers, and authors of consensus guidelines for the safe use of medicines.

Causality Assessment of Olfactory and Gustatory Dysfunction Associated with Intranasal Fluticasone Propionate: Application of the Bradford Hill Criteria

Causality assessment is crucial to post-marketing pharmacovigilance and helps optimize safe and appropriate use of medicines by patients in the real world. Self-reported olfactory and gustatory dysfunction are common in the general population as well as in patients with allergic rhinitis and nasal polyposis. Intranasal corticosteroids, including intranasal fluticasone propionate (INFP), are amongst the most effective drugs indicated in the treatment of allergic rhinitis and nasal polyposis. While intranasal corticosteroids are associated with olfactory and gustatory dysfunction and are currently labeled for these adverse events, causality assessment has not been performed to date. Although there is no single widely accepted method to assess causality in pharmacovigilance, the Bradford Hill criteria offer a robust and comprehensive approach because nine distinct aspects of an observed potential drug–event association are assessed. In this literature-based narrative review, Hill’s criteria were applied to determine causal inference between INFP and olfactory and gustatory dysfunction.

A supervised adverse drug reaction signalling framework imitating Bradford Hill's causality considerations

Big longitudinal observational medical data potentially hold a wealth of information and have been recognised as potential sources for gaining new drug safety knowledge. Unfortunately there are many complexities and underlying issues when analysing longitudinal observational data. Due to these complexities, existing methods for large-scale detection of negative side effects using observational data all tend to have issues distinguishing between association and causality. New methods that can better discriminate causal and non-causal relationships need to be developed to fully utilise the data. In this paper we propose using a set of causality considerations developed by the epidemiologist Bradford Hill as a basis for engineering features that enable the application of supervised learning for the problem of detecting negative side effects. The Bradford Hill considerations look at various perspectives of a drug and outcome relationship to determine whether it shows causal traits. We taught a classifier to find patterns within these perspectives and it learned to discriminate between association and causality. The novelty of this research is the combination of supervised learning and Bradford Hill's causality considerations to automate the Bradford Hill's causality assessment. We evaluated the framework on a drug safety gold standard known as the observational medical outcomes partnership's non-specified association reference set. The methodology obtained excellent discrimination ability with area under the curves ranging between 0.792 and 0.940 (existing method optimal: 0.73) and a mean average precision of 0.640 (existing method optimal: 0.141). The proposed features can be calculated efficiently and be readily updated, making the framework suitable for big observational data.

Evaluating weight of evidence in the mystery of Balkan endemic nephropathy

Balkan endemic nephropathy (BEN) is a chronic, progressive wasting disease of the kidneys, endemic in certain rural regions of the Balkan nations Croatia, Serbia, Bulgaria, and Romania. It is irreversible and ultimately fatal. Though this disease was first described in the 1950s, its causes have been a mystery and a source of much academic and clinical contention. Possible etiologic agents that have been explored include exposure to metals and metalloids, viruses and bacteria, and the dietary toxins aristolochic acid (AA) and ochratoxin A (OTA). AA is a toxin produced by weeds of the genus Aristolochia, common in Balkan wheat fields. Aristolochia seeds may intermingle with harvested grains and thus inadvertently enter human diets. OTA is a mycotoxin (fungal toxin) common in many foods, including cereal grains. In this study, we analyzed the weight of evidence for each of the suspected causes of BEN using the Bradford Hill criteria (BHC): nine conditions that determine weight of evidence for a causal relationship between an agent and a disease. Each agent postulated to cause BEN was evaluated using the nine criteria, and for each criterion was given a rating based on the strength of the association between exposure to the substance and BEN. From the overall available scientific evidence for each of these suspected risk factors, AA is the agent with the greatest weight of evidence in causing BEN. We describe other methods for testing causality from epidemiological studies, which support this conclusion of AA causing BEN.

Identifying plausible adverse drug reactions using knowledge extracted from the literature

Pharmacovigilance involves continually monitoring drug safety after drugs are put to market. To aid this process; algorithms for the identification of strongly correlated drug/adverse drug reaction (ADR) pairs from data sources such as adverse event reporting systems or Electronic Health Records have been developed. These methods are generally statistical in nature, and do not draw upon the large volumes of knowledge embedded in the biomedical literature. In this paper, we investigate the ability of scalable Literature Based Discovery (LBD) methods to identify side effects of pharmaceutical agents. The advantage of LBD methods is that they can provide evidence from the literature to support the plausibility of a drug/ADR association, thereby assisting human review to validate the signal, which is an essential component of pharmacovigilance. To do so, we draw upon vast repositories of knowledge that has been extracted from the biomedical literature by two Natural Language Processing tools, MetaMap and SemRep. We evaluate two LBD methods that scale comfortably to the volume of knowledge available in these repositories. Specifically, we evaluate Reflective Random Indexing (RRI), a model based on concept-level co-occurrence, and Predication-based Semantic Indexing (PSI), a model that encodes the nature of the relationship between concepts to support reasoning analogically about drug-effect relationships. An evaluation set was constructed from the Side Effect Resource 2 (SIDER2), which contains known drug/ADR relations, and models were evaluated for their ability to "rediscover" these relations. In this paper, we demonstrate that both RRI and PSI can recover known drug-adverse event associations. However, PSI performed better overall, and has the additional advantage of being able to recover the literature underlying the reasoning pathways it used to make its predictions.

Baclofen for the treatment of pediatric GERD

BACKGROUND AND AIM

Baclofen, a γ-aminobutyric acid receptor agonist, has been shown to reduce the episodes of gastroesophageal reflux (GER) by reducing the incidence of transient lower esophageal sphincter relaxations. Although baclofen has been shown to reduce reflux symptoms in adults, data in pediatric patients are limited. The aim of the study was to evaluate the efficacy of baclofen in children with refractory GER.

METHODS

Medical charts of patients 1 to 18 years of age treated with baclofen for persistent GER symptoms were reviewed retrospectively. Short-term (at first clinic visit) and long-term (12 months) clinical responses were assessed.

RESULTS

A total of 53 patients were included in the final analysis. The mean duration of illness was 1.5 years and the mean age was 6.1 years. All of the patients were taking either once- (53%) or twice-daily (47%) doses of proton pump inhibitors (PPIs) at the time of initiation of baclofen. Thirty-five (66%) patients experienced a significant reduction in clinical symptoms at their first follow-up visit. In the remaining 18 patients, however, baclofen was stopped because of either no response (n = 15) or adverse events (n = 3). A total of 27 patients continued treatment and were assessed for long-term response. Of those, 22 (81%) had a sustained response to baclofen at 12 months, whereas 5 (19%) lost response. We recognized no clinical characteristic differences between those with and without a response to baclofen at either time point.

CONCLUSIONS

Baclofen can be used as supplemental therapy to proton pump inhibitors in children with refractory GER; however, prospective trials are needed to further validate our results and assess safety.

Forensic epidemiology: a method for investigating and quantifying specific causation

The field of forensic epidemiology was initially introduced as a systematic approach to the investigation of acts of bioterrorism. In recent years, however, the applications of forensic epidemiology have expanded greatly, covering a wide range of medicolegal issues routinely encountered in both criminal and civil court settings. Forensic epidemiology provides a method of evaluating causation in groups and individuals based in the application of the Hill Criteria, with conclusions given in terms of relative or comparative risk, or as a Probability of Causation. The purpose of this paper is to give a brief overview of the methods and applications of forensic epidemiology.

Work-relatedness of low back pain in nursing personnel: a systematic review

BACKGROUND

Although non-specific low back pain (LBP) is known to be multifactorial, studies from across the globe have documented their higher prevalence in nurses. This systematic review was conducted to ascertain whether this much-documented association constitutes a causal relationship, and whether there is a discernible threshold of exposures associated with this elevated risk.

METHODS

PRISMA guidelines were followed and standard critical appraisal tools were applied. The outcome of interest was non-specific LBP or back injury; exposure was "performing nursing duties." Applicable studies, published in English during 1980-2012, were identified through database searches, screened against preset inclusion/exclusion criteria. Ergonomic assessments of nursing tasks were included along with epidemiological studies. Bradford Hill considerations for causation were utilized as a framework for discussing findings.

FINDINGS

Of 987 studies identified, 89 qualified for inclusion, comprising 21 longitudinal, 36 cross-sectional analytic, 23 descriptive biomechanical/ergonomic, and 9 review studies. Overall studies showed that nursing activities conferred increased risk for, and were associated with back disorders regardless of nursing technique, personal characteristics, and non-work-related factors. Patient handling appears to confer the highest risk, but other nursing duties are also associated with elevated risk, and confound dose-response assessments related to patient handling alone. Associations were strong, consistent, temporally possible, plausible, coherent, and analogous to other exposure-outcomes, with risk estimates ranging from 1·2 to 5·5 depending on definitions. A threshold of nursing activities below which the risk of back disorders is not elevated has not been established.

INTERPRETATION

Notwithstanding the bio-psycho-social nature of LBP, and complexities of studying this area, sufficient evidence exists of a causal relationship between nursing tasks and back disorders to warrant new policies.

Assessing cardiovascular drug safety for clinical decision-making

Optimal therapeutic decision-making requires integration of patient-specific and therapy-specific information at the point of care, particularly when treating patients with complex cardiovascular conditions. The formidable task for the prescriber is to synthesize information about all therapeutic options and match the best treatment with the characteristics of the individual patient. Computerized decision support systems have been developed with the goal of integrating such information and presenting the acceptable therapeutic options on the basis of their effectiveness, often with limited consideration of their safety for a specific patient. Assessing the safety of therapies relative to each patient is difficult, and sometimes impossible, because the evidence required to make such an assessment is either imperfect or does not exist. In addition, many of the alerts sent to prescribers by decision-support systems are not perceived as credible, and 'alert fatigue' causes warnings to be ignored putting patients at risk of harm. The CredibleMeds.org and BrugadaDrugs.org websites are prototypes for evidence-based sources of safety information that rank drugs for their risk of a specific form of drug toxicity-in these cases, drug-induced arrhythmias. Broad incorporation of this type of information in electronic prescribing algorithms and clinical decision support could speed the evolution of safe personalized medicine.

Atrial fibrillation and the use of oral bisphosphonates

Background:

Epidemiological studies investigating a possible association between bisphosphonates and atrial fibrillation (AF) have reported conflicting findings. The objective of our study was to determine whether exposure to oral nitrogen-containing bisphosphonates alendronate and risedronate are associated with increased incidence of atrial fibrillation.

Methods:

In a retrospective cohort study we analyzed data from three large independent databases, two from the United States (MarketScan^® and Ingenix^®) and one from the United Kingdom (THIN). 144,548 women, age 50–89, bisphosphonate users during 2002–2005 were compared to 668,891 sex- and age-matched controls (1:4). Our primary outcome measure was new incident atrial fibrillation for up to three years; Cox models adjusted for disease and drug history were used to estimated relative risks.

Results:

We identified a total of 8,001, 1,984, and 817 AF cases in oral bisphosphonate users and nonusers during 744,340 (MarketScan), 243,898 (Ingenix), and 148,779 (THIN) person-years of follow-up, respectively. Compared to nonusers, overall adjusted relative risk (adjRR) (95% confidence interval [CI]) for AF in oral bisphosphonates users was 0.92 (0.85–0.99; MarketScan), 1.00 (0.87–1.16; Ingenix), and 0.97 (0.79–1.20; THIN); overall adjRR (95% CI) for any cardiac dysrrhythmia for MarketScan was 1.01 (0.98–1.05), Ingenix 1.06 (0.99–1.13), and THIN 0.97 (0.79–1.20).

Conclusions:

In all three databases from the two countries, the risk of AF or cardiac dysrrhythmia was not increased in postmenopausal women treated for up to three years with oral alendronate or risedronate.

Neuroleptic malignant syndrome: mechanisms, interactions, and causality

This review focuses on new data from recent publications concerning how compounding interactions between different thermoregulatory pathways influence the development of hyperthermia and/or neuroleptic malignant syndrome (NMS), and the fundamental issue of the presumed causal role of antipsychotic drugs. The formal criteria for substantiating cause-effect relationships in medical science, established by Hill, are applied to NMS and, for comparison, also to malignant hyperthermia and serotonin toxicity. The risk of morbidities related to hyperthermia is reviewed from human and experimental data: temperatures in excess of 39.5°C cause physiological and cellular dysfunction and high mortality. The most temperature-sensitive elements of neural cells are mitochondrial and plasma membranes, in which irreversible changes occur around 40°C. Temperatures of up to 39°C are "normal" in mammals, so, the term hyperthermia should be reserved for temperatures of 39.5°C or greater. The implicitly accepted presumption that NMS is a hypermetabolic and hyperthermic syndrome is questionable and does not explain the extensive morbidity in the majority of cases, where the temperature is less than 39°C. The thermoregulatory effects of dopamine and acetylcholine are outlined, especially because they are probably the main pathways by which neuroleptic drugs might affect thermoregulation. It is notable that even potent antagonism of these mechanisms rarely causes temperature elevation and that multiple mechanisms, including the acute phase response, stress-induced hyperthermia, drugs effects, etc., involving compounding interactions, are required to precipitate hyperthermia. The application of the Hill criteria clearly supports causality for drugs inducing both MH and ST but do not support causality for NMS.

Modelling the time to onset of adverse reactions with parametric survival distributions: a potential approach to signal detection and evaluation

BACKGROUND

It has been postulated that the time to onset of adverse drug reactions is connected to the underlying pharmacological (or toxic) mechanism of adverse drug reactions whether the reaction is time dependent or not.

OBJECTIVE

We have conducted a preliminary study using the parametric modelling of the time to onset of adverse reactions as an approach to signal detection on spontaneous reporting system databases.

METHODS

We performed a parametric modelling of the reported time to onset of adverse drug reactions for which the underlying toxic mechanism is characterized. For the purpose of our study, we have used the reported liver injuries associated with bosentan, and the infections associated with the use of the tumour necrosis factor (TNF) inhibitors, adalimumab, etanercept and infliximab, which are used in Crohn's disease and rheumatoid arthritis, reported to EudraVigilance between December 2001 and September 2006.

RESULTS

The main results reflect the fact that the reported time to onset is a surrogate of the true time to onset of the reaction and combines three hazards (occurrence, diagnosis and reporting) that cannot be disentangled. Consequently, the modelling of the time to onset of reactions reported with TNF inhibitors showed differences that could reflect different pharmacological activities, indications, monitoring of the patients or different reporting patterns. These variations could also limit the interpretation of the parametric modelling.

CONCLUSIONS

Some consistency that was found between the occurrences of the infections with the TNF inhibitors suggests a causal association. There are statistical issues that are important to keep in mind when interpreting the results (the impact of the data quality on the fit of the distributions and the absence of a test of hypothesis linked to the absence of a relevant comparator). The study suggests that the modelling of the reported time to onset of adverse reactions could be a useful adjunct to other signal detection methods.

Quality of methods for assessing and reporting serious adverse events in clinical trials of cancer drugs

The validity of information regarding drug toxicity in humans depends on the quality of the methods and instruments used to assess adverse drug events (ADEs). This study evaluates the quality of instruments used to assess and report ADEs to institutional review boards (IRBs) at US cancer centers. Forms from all 49 National Cancer Institute (NCI)-designated centers were assessed for utility in abstracting event type, severity, and causality; patient demographics; safety monitoring; and consequent changes in the conduct of the relevant study. Of the 55 items considered essential for ADE reporting, one item (event description) was present on all the forms. Seventy-eight percent of the instruments prompted for global introspection of the investigator, a method known to be unreliable. Of the 34 items that our panel of experts considered essential for event description, the median number of items present was four (domain = 1-11). The use of a validated tool to describe and assess event type, severity, and causality may lead to more timely, accurate identification of safety signals in cancer treatment.

Pediatric gastroesophageal reflux clinical practice guidelines: joint recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN)

OBJECTIVE

To develop a North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) international consensus on the diagnosis and management of gastroesophageal reflux and gastroesophageal reflux disease in the pediatric population.

METHODS

An international panel of 9 pediatric gastroenterologists and 2 epidemiologists were selected by both societies, which developed these guidelines based on the Delphi principle. Statements were based on systematic literature searches using the best-available evidence from PubMed, Cumulative Index to Nursing and Allied Health Literature, and bibliographies. The committee convened in face-to-face meetings 3 times. Consensus was achieved for all recommendations through nominal group technique, a structured, quantitative method. Articles were evaluated using the Oxford Centre for Evidence-based Medicine Levels of Evidence. Using the Oxford Grades of Recommendation, the quality of evidence of each of the recommendations made by the committee was determined and is summarized in appendices.

RESULTS

More than 600 articles were reviewed for this work. The document provides evidence-based guidelines for the diagnosis and management of gastroesophageal reflux and gastroesophageal reflux disease in the pediatric population.

CONCLUSIONS

This document is intended to be used in daily practice for the development of future clinical practice guidelines and as a basis for clinical trials.

Causal criteria and the problem of complex causation

Nancy Cartwright begins her recent book, Hunting Causes and Using Them, by noting that while a few years ago real causal claims were in dispute, nowadays "causality is back, and with a vengeance." In the case of the social sciences, Keith Morrison writes that "Social science asks 'why?'. Detecting causality or its corollary-prediction-is the jewel in the crown of social science research." With respect to the health sciences, Judea Pearl writes that the "research questions that motivate most studies in the health sciences are causal in nature." However, not all data used by people interested in making causal claims come from experiments that use random assignment to control and treatment groups. Indeed, much research in the social and health science depends on non-experimental, observational data. Thus, one of the most important problems in the social and health sciences concerns making warranted causal claims using non-experimental, observational data; viz., "Can observational data be used to make etiological inferences leading to warranted causal claims?" This paper examines one method of warranting causal claims that is especially widespread in epidemiology and the health sciences generally-the use of causal criteria. It is argued that cases of complex causation generally, and redundant causation-both causal overdetermination and causal preemption-specifically, undermine the use of such criteria to warrant causal claims.

The role of causal criteria in causal inferences: Bradford Hill's "aspects of association"

As noted by Wesley Salmon and many others, causal concepts are ubiquitous in every branch of theoretical science, in the practical disciplines and in everyday life. In the theoretical and practical sciences especially, people often base claims about causal relations on applications of statistical methods to data. However, the source and type of data place important constraints on the choice of statistical methods as well as on the warrant attributed to the causal claims based on the use of such methods. For example, much of the data used by people interested in making causal claims come from non-experimental, observational studies in which random allocations to treatment and control groups are not present. Thus, one of the most important problems in the social and health sciences concerns making justified causal inferences using non-experimental, observational data. In this paper, I examine one method of justifying such inferences that is especially widespread in epidemiology and the health sciences generally - the use of causal criteria. I argue that while the use of causal criteria is not appropriate for either deductive or inductive inferences, they do have an important role to play in inferences to the best explanation. As such, causal criteria, exemplified by what Bradford Hill referred to as "aspects of [statistical] associations", have an indispensible part to play in the goal of making justified causal claims.