The Impact of Litigation-Associated Reports on Signal Identification in the US FDA’s Adverse Event Reporting System

19th ISoP Annual Meeting “New Opportunities for New Generations” Bogotá, Colombia, 26–29 October, 2019

Intravenous Infusion Administration: A Comparative Study of Practices and Errors Between the United States and England and Their Implications for Patient Safety Abstract Introduction Intravenous medication administration is widely reported to be error prone. Technologies such as smart pumps have been introduced with a view to reducing these errors. An international comparison could provide evidence of their effectiveness, including consideration of contextual factors such as regulatory systems and local cultures. Objectives The aim of this study was to investigate similarities and differences in practices and error types involving intravenous medication administration in the United States and England, and summarise methodological differences necessary to perform these parallel studies. Methods We drew on findings of separate point prevalence studies conducted across hospitals in each country. In these, we compared what was being administered at the time of observation with the prescription and relevant policies, errors were classified by type and severity, and proportions of infusions featuring each error type were calculated. We also reviewed what adaptations to the US protocol were needed for England. Authors independently reviewed findings from both studies and proposed themes for comparison. In online meetings, each country’s research team clarified assumptions and explained their findings. Results Key themes included commonalities and contrasts in methods, findings, practices and policies. Although US sites made greater use of smart infusion devices, and had more precisely defined requirements around infusion device use, patterns of errors were similar. Differences among clinical contexts within each country were as marked as differences across countries. Regulatory and quality control systems shape practices, but causal relationships are complex. Conclusion Infusion administration is a complex adaptive system with multiple interacting agents (professionals, patients, software systems, etc.) that respond in rich ways to their environments; safety depends on complex, interrelated factors.

Evaluating Renal Stress Using Pharmacokinetic Urinary Biomarker Data in Critically Ill Patients Receiving Vancomycin and/or Piperacillin–Tazobactam: A Secondary Analysis of the Multicenter Sapphire Study Abstract Introduction A drug combination that has gained recent attention for an additive risk of nephrotoxicity is vancomycin plus piperacillin–tazobactam. Clinicians need to better understand whether tubular cell stress occurs with piperacillin–tazobactam administration to establish whether renal injury associated with this combination is a valid clinical concern. Objective An evaluation of the pharmacokinetics of urinary tissue inhibitor of metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding-protein 7 (IGFBP7) for patients receiving vancomycin alone, piperacillin–tazobactam alone, and vancomycin plus piperacillin–tazobactam in combination was conducted to understand the impact on acute kidney cell stress and compare the rates of dialysis or death at 9 months among these three drug exposure types. Methods A secondary analysis of the prospective, multicenter Sapphire study (ClinicalTrials.gov identifier NCT01209169) including 35 intensive care units (ICUs) in North America and Europe was performed. Critically ill adult patients at risk for acute kidney injury (AKI) were included. Urinary [TIMP-2]∙[IGFBP7] was measured serially. Patients who received vancomycin alone, piperacillin–tazobactam alone, or vancomycin plus piperacillin–tazobactam were grouped according to their maximum AKI stage within 3 days of the first drug dose. Results Of 723 critically ill adults admitted to the ICU, 46% received either piperacillin–tazobactam (n = 110), vancomycin (n = 156), or both (n = 67). The urinary [TIMP-2]∙[IGFBP7] was highest on day 1 for the combination group. AKI stage 2/3 occurred more frequently in patients receiving the drug combination than in those receiving piperacillin–tazobactam alone (p = 0.03) but not vancomycin alone (p = 0.29). Risk of death or dialysis at 9 months was greatest for vancomycin plus piperacillin–tazobactam (48%) and similar for patients receiving vancomycin alone (29%) or piperacillin–tazobactam alone (35%) (p = 0.03 for unadjusted and p = 0.048 after adjusting for covariates). Conclusion After exposure to piperacillin–tazobactam and vancomycin in combination, there was a greater release of AKI biomarkers in patients who develop AKI than with piperacillin–tazobactam or vancomycin monotherapy and the combination is associated with possible increased long-term adverse outcomes.

Cardiovascular Safety of Prucalopride in Patients with Chronic Constipation: A Multinational Population-Based Cohort Study Abstract Introduction The serotonin 5-HT4 receptor agonist prucalopride is approved in the European Union for the treatment of chronic constipation. This offered the unique opportunity to include real-world observational data on cardiovascular safety in the new drug application for approval of prucalopride in the USA. Methods This observational population-based cohort study (EUPAS9200) conducted in five data sources (three in the UK, one in Sweden, and one in Germany [which was subsequently excluded from the pooled analyses]) aimed to estimate the pooled adjusted incidence rate ratio for major adverse cardiovascular events (defined as hospitalization for non-fatal acute myocardial infarction or stroke, and in-hospital cardiovascular death) in adult initiators of prucalopride compared with initiators of polyethylene glycol 3350 (PEG) following a common protocol. Standardized incidence rates and incidence rate ratios of major adverse cardiovascular events were derived using propensity score stratification. Sensitivity analyses explored the impact of exposure definition, outcome categories, interim cancer, and unmeasured confounding. Results The pooled analyses included 5715 initiators of prucalopride and 29,372 initiators of PEG. Average duration of use was 175 days for prucalopride and 82 days for PEG. The pooled standardized incidence rate per 1000 person-years (95% confidence interval) of major adverse cardiovascular events was 6.57 (3.90–10.39) for patients initiating prucalopride and 10.24 (6.97–14.13) for PEG. The pooled adjusted incidence rate ratio for major adverse cardiovascular events was 0.64 (95% confidence interval 0.36–1.14). Results remained consistent in various sensitivity analyses. Conclusions The pooled incidence rate ratio estimate was consistent with no indication of an increased risk above the pre-specified safety threshold of 3.00 for major adverse cardiovascular events in patients with chronic constipation using prucalopride as compared with PEG.

Comparative Effectiveness and Safety of Direct Oral Anticoagulants in Patients with Atrial Fibrillation: A Systematic Review and Meta-Analysis of Observational Studies Abstract Background There are no head-to-head randomized controlled trials comparing different direct oral anticoagulants (DOACs). Thus, we systematically reviewed and meta-analyzed observational studies assessing the comparative effectiveness and safety of DOACs for stroke prevention in patients with atrial fibrillation (AF). Methods We systematically searched MEDLINE and EMBASE up to February 2019 for observational studies comparing different DOACs head-to-head in patients with AF. Two independent reviewers identified studies, extracted data, and assessed the risk of bias using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool. Random-effects models were used to meta-analyze data across higher-quality studies. Results We identified 25 cohort studies including 1,079,565 patients with AF treated with DOACs. Meta-analysis of the 19 studies at moderate risk of bias yielded a similar risk of ischemic stroke for rivaroxaban versus dabigatran (six studies; hazard ratio [HR] 0.93; 95% confidence interval [CI] 0.83–1.04; I2: 0%), apixaban versus dabigatran (five studies; HR 0.94; 95% CI 0.82–1.09; I2: 0%), and apixaban versus rivaroxaban (four studies; HR 1.07; 95% CI 0.93–1.23; I2: 0%). Regarding major bleeding, there was an increased risk for rivaroxaban versus dabigatran (six studies; HR 1.33; 95% CI 1.20–1.47; I2: 22%) and decreased risks for apixaban versus either dabigatran (eight studies; HR 0.71; 95% CI 0.64–0.78; I2: 0%) or rivaroxaban (eight studies; HR 0.56; 95% CI 0.48–0.65; I2: 69%). Conclusions As head-to-head trials comparing different DOACs do not exist, available evidence derives exclusively from observational studies. These data suggest that while dabigatran, rivaroxaban, and apixaban have a similar effect on the risk of ischemic stroke, apixaban may be associated with a decreased risk of major bleeding compared with either dabigatran or rivaroxaban.

Pharmacovigilance as Scientific Discovery: An Argument for Trans-Disciplinarity Abstract Pharmacovigilance currently faces several unsolved challenges. Of particular importance are issues concerning how to ascertain, collect, confirm, and communicate the best evidence to assist the clinical choice for individual patients. Here, we propose that these practical challenges partially stem from deeper fundamental issues concerning the epistemology of pharmacovigilance. After reviewing some of the persistent challenges, recent measures, and suggestions in the current pharmacovigilance literature, we support the argument that the detection of potential adverse drug reactions ought to be seen as a serendipitous scientific discovery. We further take up recent innovations from the multidisciplinary field of serendipity research about the importance of networks, diversity of expertise, and plurality of methodological perspectives for cultivating serendipitous discovery. Following this discussion, we explore how pharmacovigilance could be systematized in a way that optimizes serendipitous discoveries of untargeted drug effects, emerging from the clinical application. Specifically, we argue for the promotion of a trans-disciplinary responsive network of scientists and stakeholders. Trans-disciplinarity includes extending the involvement of stakeholders beyond the regulatory community, integrating diverse methods and sources of evidence, and enhancing the ability of diverse groups to raise signals of harms that ought to be followed up by the network. Consequently, promoting a trans-disciplinary approach to pharmacovigilance is a long-term effort that requires structural changes in medical education, research, and enterprise. We suggest a number of such changes, discuss to what extent they are already in process, and indicate the advantages from both epistemological and ethical perspectives.

Unintended Effects of Communicating About Drug Safety Issues: A Critical Review of the Literature Abstract Communications about the safety and effectiveness of human drugs can influence patients’ and prescribers’ perceptions and behaviors, which in turn can affect the public’s health more broadly. We conducted a critical review of the literature on the unintended effects from communicating information to the public about safety issues with prescription and over-the-counter drugs. We searched PubMed for peer-reviewed studies published from 1990 to 2017 where study authors reported probable unintended effects of communicating drug safety. The types of communications included in these studies were news reports, direct-to-consumer advertisements, and those released by government agencies. Among the 26 studies identified, the most commonly reported unintended effects were decreased drug use or discontinuation. Other unintended effects included spillover to populations not targeted by the communications (e.g., discontinuation of antidepressants among adults following communications concerning use among youth), shifts in clinical diagnoses (e.g., fewer diagnoses of depression), increased use of alternative therapies, and other undesirable behaviors (e.g., possible increased suicide attempts because antidepressants were discontinued). Limitations to the literature include the inability to establish causation or to isolate the effects of multiple communication sources and messages. Further, because the intended effect of many communications was not known, our study was limited by challenges in defining some effects as unintended. Most studies used health insurer claims data to identify unintended effects of communications, which provide an incomplete picture; few used self-reported or other methodologies that could help illuminate the reasons underlying the effects observed in the claims data. Best practices for communicating about the potential benefits and harms of drugs in a manner that minimizes negative unintended effects are needed to protect and improve public health.

Pooling Different Safety Data Sources: Impact of Combining Solicited and Spontaneous Reports on Signal Detection In Pharmacovigilance Abstract Introduction The volume of adverse events (AEs) collected, analysed, and reported has been increasing at a rapid rate for over the past 10 years, largely due to the growth of solicited programmes. The proportion of various forms of solicited case data has evolved over time, with the main relative volume increase coming from Patient Support Programmes. In this study, we sought to examine the impact of the pooling of AE report data from solicited sources with data from spontaneous sources to safety signal detection using disproportionality analysis methods. Methods Two conditions were explored in which disproportionality scores from hypothetical drugs were evaluated in a simulated safety database. The first condition held occurrence of events constant and varied solicited case volume, while the second condition varied both proportion of occurrence of events and solicited case volume. Results In the first setting, where all AE terms have the same probability to occur with any drug, increasing volumes of solicited cases while keeping occurrence of events constant leads to reduced variability in disproportionality scores, consequently reducing or eliminating identified signals of disproportionate reporting. In the second setting, varying both case volume and reporting rates can mask true safety signals and falsely identify signals where there are none. Conclusions This analysis of simulated data suggests that pooling AE data from solicited sources with spontaneous case data may impact the results of disproportionality analyses, masking true safety signals and identifying false positives. Therefore, increased volumes of safety data do not necessarily correlate with improved safety signal detection.

Study Design and Cohort Comparability in a Study of Major Cardiovascular Events in New Users of Prucalopride Versus Polyethylene Glycol 3350 Abstract Introduction Given prior safety experience with other 5-HT4 agonists for chronic constipation, an observational, population-based cohort study in five data sources from Germany, Sweden, and the UK was conducted to evaluate the cardiovascular safety of prucalopride. Objectives Our objective is to describe the methods and resulting comparability of cohorts in a multi-database, multinational study of prucalopride initiators and polyethylene glycol 3350 (PEG) initiators following a harmonized protocol. Methods Prucalopride initiators were matched on age, sex, and index date to PEG initiators (1:5 ratio). Study exposures, cardiovascular risk factors, and other covariates were identified from healthcare utilization codes harmonized across databases. Cardiovascular outcomes were identified using database-specific algorithms based on diagnosis codes. The propensity score (PS) in each database was estimated using logistic regression, with prucalopride versus PEG as the outcome and including clinically relevant variables associated with major adverse cardiovascular events. Results In total, 12,030 prucalopride initiators and 59,985 PEG initiators were identified. After matching and trimming, cohorts from the UK and Sweden were well-balanced for cardiovascular risk factors and cancer. However, in Germany, PEG initiators remained older and sicker than prucalopride initiators. The prevalence of these characteristics also differed from those in the UK and Sweden. The pooled analyses included only data from the UK and Sweden. Conclusions Matching, trimming, and PS stratification yielded comparable cohorts in four of five data sources. Use of these methods could not achieve balance for key covariates within the German cohort, likely due to reimbursement differences in Germany.