Regulatory, health technology assessment and company interactions: the current landscape and future ecosystem for drug development, review and reimbursement.

BACKGROUND: Multi-stakeholder interactions have evolved at product and policy levels. There is a need to assess the current and future landscape of interactions between companies, and regulatory and HTA agencies to address challenges and identify areas for improvement. OBJECTIVES: The aims of this study were to review the current interactions within and across regulatory and HTA agencies, and companies' experiences in engaging in these activities; to assess the added value of interactions as well as limitations; to explore the future ecosystem for stakeholder interactions. METHOD: Three separate questionnaires were developed for companies, regulators and HTA agencies, respectively, to assess their experiences and perceptions. The responses were analyzed using descriptive statistics and discussed at a multi-stakeholder workshop. Key outcomes from the surveys and workshop discussion were reported. RESULTS: All seven regulators and seven HTA agencies in the survey indicated that they had stakeholder interactions. More formal collaboration occurred with regulators compared with HTA agencies. All nine companies have taken early advice but indicated the need for future prioritization. Success indicators can be built at the product and therapy levels, with the added value of faster patient access. Four principles were proposed for the future ecosystem: separate remit and functions between regulators and HTA; align processes; converge evidence requirements where possible; increase transparency. CONCLUSIONS: This research brought together regulators, HTA agencies, companies to examine how they interact with one another. We propose measures of value and make recommendations on future evolution to enable better evidence generation and improve regulatory and HTA decision-making.

Genetic susceptibility to radiation-induced breast cancer after Hodgkin lymphoma.

Female Hodgkin lymphoma (HL) patients treated with chest radiotherapy (RT) have a very high risk of breast cancer. The contribution of genetic factors to this risk is unclear. We therefore examined 211 155 germline single-nucleotide polymorphisms (SNPs) for gene-radiation interaction on breast cancer risk in a case-only analysis including 327 breast cancer patients after chest RT for HL and 4671 first primary breast cancer patients. Nine SNPs showed statistically significant interaction with RT on breast cancer risk (false discovery rate, <20%), of which 1 SNP in the PVT1 oncogene attained the Bonferroni threshold for statistical significance. A polygenic risk score (PRS) composed of these SNPs (RT-interaction-PRS) and a previously published breast cancer PRS (BC-PRS) derived in the general population were evaluated in a case-control analysis comprising the 327 chest-irradiated HL patients with breast cancer and 491 chest-irradiated HL patients without breast cancer. Patients in the highest tertile of the RT-interaction-PRS had a 1.6-fold higher breast cancer risk than those in the lowest tertile. Remarkably, we observed a fourfold increased RT-induced breast cancer risk in the highest compared with the lowest decile of the BC-PRS. On a continuous scale, breast cancer risk increased 1.4-fold per standard deviation of the BC-PRS, similar to the effect size found in the general population. This study demonstrates that genetic factors influence breast cancer risk after chest RT for HL. Given the high absolute breast cancer risk in radiation-exposed women, these results can have important implications for the management of current HL survivors and future patients.

Comparing risk of major bleeding between users of different oral anticoagulants in patients with nonvalvular atrial fibrillation.

AIMS: The introduction of direct oral anticoagulants (DOACs) has broadened the treatment arsenal for nonvalvular atrial fibrillation, but observational studies on the benefit-risk balance of DOACs compared to vitamin K antagonists (VKAs) are needed. The aim of this study was to characterize the risk of major bleeding in DOAC users using longitudinal data collected from electronic health care databases from 4 different EU-countries analysed with a common study protocol. METHODS: A cohort study was conducted among new users (≥18 years) of DOACs or VKAs with nonvalvular atrial fibrillation using data from the UK, Spain, Germany and Denmark. The incidence of major bleeding events (overall and by bleeding site) was compared between current use of DOACs and VKAs. Cox regression analysis was used to calculate hazard ratios and 95% confidence intervals (CI) and adjust for confounders. RESULTS/CONCLUSION: Overall, 251 719 patients were included across the 4 study cohorts (mean age ~75 years, % females between 41.3 and 54.3%), with overall hazard ratios of major bleeding risk for DOACs vs VKAs ranging between 0.84 (95% CI: 0.79-0.90) in Denmark and 1.13 (95% CI 1.02-1.25) in the UK. When stratifying according to the bleeding site, risk of gastrointestinal bleeding was increased by 48-67% in dabigatran users and 30-50% for rivaroxaban users compared to VKA users in all data sources except Denmark. Compared to VKAs, apixaban was not associated with an increased risk of gastrointestinal bleeding in all data sources and seemed to be associated with the lowest risk of major bleeding events compared to dabigatran and rivaroxaban.

Major bleeding in users of direct oral anticoagulants in atrial fibrillation: A pooled analysis of results from multiple population-based cohort studies.

OBJECTIVE: To establish the risk of major bleeding in direct oral anticoagulant (DOAC) users (overall and by class) versus vitamin K antagonist (VKA) users, using health care databases from four European countries and six provinces in Canada. METHODS: A retrospective cohort study was performed according to a similar protocol. First-users of VKAs or DOACs with a diagnosis of non-valvular atrial fibrillation (NVAF) were included. The main outcome of interest was major bleeding and secondary outcomes included gastrointestinal (GI) bleeding and intracranial haemorrhage (ICH). Incidence rates of events per 1000 person years were calculated. Hazard ratios (HRs) and 95% confidence intervals (95% CI) were estimated using a Cox proportional hazard regression model. Exposure and confounders were measured and analysed in a time-dependant way. Risk estimates were pooled using a random effect model. RESULTS: 421 523 patients were included. The risk of major bleeding for the group of DOACs compared to VKAs showed a pooled HR of 0.94 (95% CI: 0.87-1.02). Rivaroxaban showed a modestly increased risk (HR 1.11, 95% CI: 1.06-1.16). Apixaban and dabigatran showed a decreased risk of respectively HR 0.76 (95% CI: 0.69-0.84) and HR 0.85 (95% CI: 0.75-0.96). CONCLUSIONS: This study confirms that the risk of major bleeding of DOACs compared to VKAs is not increased when combining all DOACs. However, we observed a modest higher risk of major bleeding for rivaroxaban, whereas for apixaban and dabigatran lower risks of major bleeding were observed compared to VKAs.

Advanced therapy medicinal product manufacturing under the hospital exemption and other exemption pathways in seven European Union countries.

BACKGROUND AIMS: As part of the advanced therapy medicinal product (ATMP) regulation, the hospital exemption (HE) was enacted to accommodate manufacturing of custom-made ATMPs for treatment purposes in the European Union (EU). However, how the HE pathway has been used in practice is largely unknown. METHODS: Using a survey and interviews, we provide the product characteristics, scale and motivation for ATMP manufacturing under HE and other, non-ATMP-specific exemption pathways in seven European countries. RESULTS: Results show that ATMPs were manufactured under HE by public facilities located in Finland, Germany, Italy and the Netherlands, which enabled availability of a modest number of ATMPs (n = 12) between 2009 and 2017. These ATMPs were shown to have close proximity to clinical practice, and manufacturing was primarily motivated by clinical needs and clinical experience. Public facilities used HE when patients could not obtain treatment in ongoing or future trials. Regulatory aspects motivated (Finland, Italy, the Netherlands) or limited (Belgium, Germany) HE utilization, whereas financial resources generally limited HE utilization by public facilities. Public facilities manufactured other ATMPs (n = 11) under named patient use (NPU) between 2015 and 2017 and used NPU in a similar fashion as HE. The scale of manufacturing under HE over 9 years was shown to be rather limited in comparison to manufacturing under NPU over 3 years. In Germany, ATMPs were mainly manufactured by facilities of private companies under HE. CONCLUSIONS: The HE enables availability of ATMPs with close proximity to clinical practice. Yet in some countries, HE provisions limit utilization, whereas commercial developments could be undermined by private HE licenses in Germany. Transparency through a public EU-wide registry and guidance for distinguishing between ATMPs that are or are not commercially viable as well as public-private engagements are needed to optimize the use of the HE pathway and regulatory pathways for commercial development in a complementary fashion.

Adjusting for unmeasured confounding using validation data: Simplified two-stage calibration for survival and dichotomous outcomes.

In epidemiology, one typically wants to estimate the risk of an outcome associated with an exposure after adjusting for confounders. Sometimes, outcome and exposure and maybe some confounders are available in a large data set, whereas some important confounders are only available in a validation data set that is typically a subset of the main data set. A generally applicable method in this situation is the two-stage calibration (TSC) method. We present a simplified easy-to-implement version of the TSC for the case where the validation data are a subset of the main data. We compared the simplified version to the standard TSC version for incidence rate ratios, odds ratios, relative risks, and hazard ratios using simulated data, and the simplified version performed better than our implementation of the standard version. The simplified version was also tested on real data and performed well.

The association of diabetes mellitus and insulin treatment with expression of insulin-related proteins in breast tumors.

BACKGROUND: The insulin receptor (INSR) and the insulin growth factor 1 receptor (IGF1R) play important roles in the etiology of both diabetes mellitus and breast cancer. We aimed to evaluate the expression of hormone and insulin-related proteins within or related to the PI3K and MAPK pathway in breast tumors of women with or without diabetes mellitus, treated with or without insulin (analogues). METHODS: Immunohistochemistry was performed on tumor tissue of 312 women with invasive breast cancer, with or without pre-existing diabetes mellitus, diagnosed in 2000-2010, who were randomly selected from a Danish breast cancer cohort. Women with diabetes were 2:1 frequency matched by year of birth and age at breast cancer diagnosis to those without diabetes. Tumor Microarrays were successfully stained for p-ER, EGFR, p-ERK1/2, p-mTOR, and IGF1R, and scored by a breast pathologist. Associations of expression of these proteins with diabetes, insulin treatment (human insulin and insulin analogues) and other diabetes medication were evaluated by multivariable logistic regression adjusting for menopause and BMI; effect modification by menopausal status, BMI, and ER status was assessed using interactions terms. RESULTS: We found no significant differences in expression of any of the proteins in breast tumors of women with (n = 211) and without diabetes (n = 101). Among women with diabetes, insulin use (n = 53) was significantly associated with higher tumor protein expression of IGF1R (OR = 2.36; 95%CI:1.02-5.52; p = 0.04) and p-mTOR (OR = 2.35; 95%CI:1.13-4.88; p = 0.02), especially among women treated with insulin analogues. Menopause seemed to modified the association between insulin and IGF1R expression (p = 0.07); the difference in IGF1R expression was only observed in tumors of premenopausal women (OR = 5.10; 95%CI:1.36-19.14; p = 0.02). We found no associations between other types of diabetes medication, such as metformin, and protein expression of the five proteins evaluated. CONCLUSIONS: In our study, breast tumors of women with pre-existing diabetes did not show an altered expression of selected PI3K/MAPK pathway-related proteins. We observed an association between insulin treatment and increased p-mTOR and IGF1R expression of breast tumors, especially in premenopausal women. This observation, if confirmed, might be clinically relevant since the use of IGF1R and mTOR inhibitors are currently investigated in clinical trials.

Cancer risk among insulin users: comparing analogues with human insulin in the CARING five-country cohort study.

AIMS/HYPOTHESIS: The aim of this work was to investigate the relationship between use of certain insulins and risk for cancer, when addressing the limitations and biases involved in previous studies. METHODS: National Health Registries from Denmark (1996-2010), Finland (1996-2011), Norway (2005-2010) and Sweden (2007-2012) and the UK Clinical Practice Research Datalink database (1987-2013) were used to conduct a cohort study on new insulin users (N = 327,112). By using a common data model and semi-aggregate approach, we pooled individual-level records from five cohorts and applied Poisson regression models. For each of ten cancer sites studied, we estimated the rate ratios (RRs) by duration (≤0.5, 0.5-1, 1-2, 2-3, 3-4, 4-5, 5-6 and >6 years) of cumulative exposure to insulin glargine or insulin detemir relative to that of human insulin. RESULTS: A total of 21,390 cancer cases occurred during a mean follow-up of 4.6 years. No trend with cumulative treatment time for insulin glargine relative to human insulin was observed in risk for any of the ten studied cancer types. Of the 136 associations tested in the main analysis, only a few increased and decreased risks were found: among women, a higher risk was observed for colorectal (RR 1.54, 95% CI 1.06, 2.25) and endometrial cancer (RR 1.78, 95% CI 1.07, 2.94) for ≤0.5 years of treatment and for malignant melanoma for 2-3 years (RR 1.92, 95% CI 1.02, 3.61) and 4-5 years (RR 3.55, 95% CI 1.68, 7.47]); among men, a lower risk was observed for pancreatic cancer for 2-3 years (RR 0.34, 95% CI 0.17, 0.66) and for liver cancer for 3-4 years (RR 0.36, 95% CI 0.14, 0.94) and >6 years (RR 0.22, 95% CI 0.05, 0.92). Comparisons of insulin detemir with human insulin also showed no consistent differences. CONCLUSIONS/INTERPRETATION: The present multi-country study found no evidence of consistent differences in risk for ten cancers for insulin glargine or insulin detemir use compared with human insulin, at follow-up exceeding 5 years.

Infradiaphragmatic irradiation and high procarbazine doses increase colorectal cancer risk in Hodgkin lymphoma survivors.

BACKGROUND: Hodgkin lymphoma (HL) survivors are at increased risk of second malignancies, but few studies have assessed colorectal cancer (CRC) risk after HL treatment. We assessed long-term, subsite-specific CRC risk associated with specific radiation fields and chemotherapy regimens. METHODS: In a Dutch cohort of 3121 5-year HL survivors treated between 1965 and 1995, subsite-specific CRC incidence was compared with general population rates. Treatment effects were quantified by Cox regression analyses. RESULTS: After a median follow-up of 22.9 years, 55 patients developed CRC. The standardized incidence ratios (SIR) was 2.4-fold increased (95% confidence interval (95%CI) 1.8-3.2), leading to 5.7 excess cases per 10 000 patient-years. Risk was still increased 30 years after HL treatment (SIR: 2.8; 95%CI: 1.6-4.6). The highest (SIR: 6.5, 95%CI: 3.3-11.3) was seen for transverse colon cancer (15.0 (95%CI: 4.3-40.8) after inverted-Y irradiation). A prescribed cumulative procarbazine dose >4.2 g m-2 was associated with a 3.3-fold higher CRC risk (95%CI: 1.8-6.1) compared to treatment without procarbazine. Patients receiving >4.2 g m-2 procarbazine and infradiaphragmatic radiotherapy had a hazard ratio of 6.8 (95%CI: 3.0-15.6) compared with patients receiving neither treatment, which is significantly higher than an additive joint effect (Padditivity=0.004). CONCLUSIONS: Colorectal cancer surveillance should be considered for HL survivors who received Infradiaphragmatic radiotherapy and a high cumulative procarbazine dose.

Use of incretin agents and risk of acute and chronic pancreatitis: A population-based cohort study.

AIM: To determine the association between the use of incretin agents (dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists) for the treatment of type 2 diabetes mellitus (T2DM) and the risk of any, acute and chronic pancreatitis. RESEARCH DESIGN AND METHODS: A population-based cohort study was conducted using data from the UK Clinical Practice Research Datalink (CPRD 2007-2012). A total of 182 428 adult patients with ≥1 non-insulin antidiabetic drug (NIAD) prescription were matched to control subjects without diabetes. Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of pancreatitis in incretin-users (N = 28 370) compared with controls and with other NIAD users. Adjustments were made for lifestyle, disease and drug history. In a sensitivity analysis, a new-user design was used. RESULTS: Current incretin users had a 1.5-fold increased risk of any pancreatitis compared with NIAD users (adjusted HR 1.47, 95% CI 1.06-2.04). In incident current incretin users the risk of any and acute pancreatitis was increased 2.1- and 2.0-fold compared with NIAD users (adjusted HR 2.12, 95% CI 1.31-3.43 and adjusted HR 1.96, 95% CI 1.13-3.41), whereas there was no increased risk found for chronic pancreatitis. CONCLUSIONS: Incretin use was associated with an increased risk of any pancreatitis. Moreover, risk of any and acute pancreatitis was higher when applying a new-user design. We were not able to detect an association with chronic pancreatitis, but the number in this subgroup was small.

Registries in European post-marketing surveillance: a retrospective analysis of centrally approved products, 2005-2013.

PURPOSE: Regulatory agencies and other stakeholders increasingly rely on data collected through registries to support their decision-making. Data from registries are a cornerstone of post-marketing surveillance for monitoring the use of medicines in clinical practice. This study was aimed at gaining further insight into the European Medicines Agency's (EMA) requests for new registries and registry studies using existing registries and to review the experience gained in their conduct. METHODS: European Public Assessment Reports were consulted to identify products for which a request for a registry was made as a condition of the marketing authorisation. All centrally authorised products that received a positive opinion of the EMA Committee for Medicinal Products for Human Use between 1 January 2005 and 31 December 2013 were included. Data regarding registry design and experiences were collected from EMA electronic record keeping systems. RESULTS: Of 392 products that received a positive Committee for Medicinal Products for Human Use opinion during 2005-2013, 31 registries were requested for 30 products in total. Sixty-five percent were product registries whereas 35% were disease registries and 71% of the registries had a primary safety objective. Most commonly reported issues with registries were delayed time to start and low patient accrual rates. CONCLUSIONS: The delays found in getting new registries up and running support the need to improve the timeliness of data collection in the post-marketing setting. Methodological challenges met in conducting this study highlighted the need for a clarification of definitions and epidemiological concepts around patient registries. The results will inform the EMA Patient Registry initiative to support use of existing patient registries for the post-authorisation benefit-risk monitoring of medicinal products. © 2017 Commonwealth of Australia. Pharmacoepidemiology & Drug Safety © 2017 John Wiley & Sons, Ltd.

Ankylosing spondylitis and risk of ischaemic heart disease: a population-based cohort study.

OBJECTIVE: To investigate the incidence and risk of ischaemic heart disease (IHD) and acute myocardial infarction (AMI), including the role of non-steroidal anti-inflammatory drugs (NSAID), in patients with ankylosing spondylitis (AS) compared with population controls. METHODS: All patients with newly diagnosed AS (n=3809) from the British Clinical Practice Research Datalink (1987-2012) were matched with up to seven persons without AS by year of birth, gender and practice (n=26 197). Incidence rate ratios (IRR) and HRs for development of IHD and AMI were calculated. Stepwise analyses were performed adjusting for age, gender, comorbidity and drug use, including NSAIDs. RESULTS: At baseline, 4.3% of the patients had IHD and 1.8% had AMI compared with 3.4% and 1.4% of the controls, respectively. After exclusion of pre-existing IHD or AMI, the IRRs were 1.18 (95% CI 0.96 to 1.46) and 0.91 (95% CI 0.65 to 1.27) for IHD and AMI, respectively. Compared with controls, the age-gender adjusted HR for developing IHD was 1.20 (95% CI 0.97 to 1.48), and for AMI 0.91 (95% CI 0.65 to 1.28). In female patients, the risk of developing IHD was increased (HR 1.88, 95% CI 1.22 to 2.90), but after adjustment for all possible risk factors only a non-significant trend was found (HR 1.31, 95% CI 0.83 to 2.08). In particular, NSAID use explained this change (HR IHD adjusted for age-gender-NSAID use 1.57, 95% CI 0.99 to 2.48). CONCLUSIONS: Female patients with AS had an increased age-adjusted risk of developing IHD, but after adjustment for NSAID use only a non-significant trend towards increased risk was found.

Characteristics and follow-up of postmarketing studies of conditionally authorized medicines in the EU.

AIM: The aim of the present study was to provide an insight into the characteristics and follow-up of postmarketing studies of medicines that were conditionally authorized in the European Union (EU). METHODS: We compiled a list of all postmarketing studies attached as specific obligations to the licence of medicines that were granted conditional marketing authorization from January 2006 to April 2014. Studies were characterized based on their objective, design, status upon marketing authorization (MA) and due data set by authorities. They were linked to online study registrations (Clinicaltrials.gov, ENCePP) to determine completion date. We described and associated characteristics of studies and medicines, and determined whether studies were completed on time. RESULTS: A total of 59 postmarketing studies were requested for 21 conditionally authorized medicines. Most studies had an interventional study design (73%), were ongoing upon MA (61%) and aimed to provide additional data on efficacy (45%). Interventional studies were more often ongoing and providing efficacy data, while observational and other studies were more often new and providing safety data. Frequent grounds for requesting postmarketing studies were 'long-term follow-up' and 'increase data on subpopulations'. Of the 34 studies eligible for follow-up analysis, 26 (76%) were completed and 17 (50%) completed on time. Actual completion time took a median (interquartile range) of 274 (-121 to 556) days longer than expected. CONCLUSIONS: Our results indicated that most postmarketing studies attached to a conditional marketing authorization were eventually completed but that half were completed with a substantial delay. The observations suggest caution when broadening the use of postmarketing studies for resolving uncertainties about benefits and risks after MA.

Insulin glargine use and breast cancer risk: Associations with cumulative exposure.

BACKGROUND: This study was aimed to assess the risk of breast cancer associated with exposure to insulin glargine in women with type 2 diabetes and evaluate whether the pattern of risk concurs with the hypothesized trend of an increase in risk with longer duration of use, taking into account previous cumulative exposure to other types of insulin. METHODS: We performed a restrospective cohort study (2002-2013) in the Clinical Practice Research Datalink among adult female patients with a first ever insulin prescription (n = 12 468). Time-dependent exposure measures were used to assess associations with duration of use of: (1) other insulin types before glargine was first prescribed (i.e. among switchers); and (2) of glargine during follow-up. Analyses were performed separately for insulin-naïve glargine users and patients switched to glargine. Cox proportional hazards models were used to derive p-trends, hazard ratios (HR) and 95% confidence intervals (CI) for breast cancer associated with glargine use. RESULTS: During 66 151 person years, 186 breast cancer cases occurred; 76 in glargine users (3.0/1000 years) and 110 in users of other insulins (2.7/1000 years). Among insulin-naïve women, no association with cumulative glargine use was observed (p-trend = 0.91), even after ≥5 years (HR = 1.06, 95% CI 0.48-2.33). Among switchers, a linear trend with years of prior exposure to other insulins was found (p-trend = 0.02). An increased risk was observed in glargine users with extensive (>3 years) past exposure to other insulins (HR = 3.17, 95% CI 1.28-7.84). A non-significant trend with cumulative glargine exposure was found among switchers (p-trend = 0.24). CONCLUSIONS: Exposure to glargine was not associated with an increased breast cancer risk in insulin-naïve patients. Exposure to other insulins prior to the start of glargine appears to be relevant when studying breast cancer risk associated with glargine use.

Benefit-risk reassessment of medicines: a retrospective analysis of all safety-related referral procedures in Europe during 2001-2012.

PURPOSE: The aim of this study was to determine the outcomes and timing within the product life cycle of all benefit-risk reassessment procedures for marketed products that were completed by the committee for medicinal product for human use during 2001-2012. METHODS: A cohort of all referral procedures for benefit-risk reassessment (Article 20, Article 31, Article 36, Article 107 procedures) for which committee for medicinal product for human use issued an opinion between 1 January 2001 and 31 December 2012 was created. The European Medicines Agency website and the Dutch Medicines Evaluation Board website were used to collect all data. RESULTS: There were a total of 73 benefit-risk reassessments during the study period; 61 reassessments for a single product and 12 reassessments for multiple products or an entire product class. Nineteen reassessments resulted in the recommendation to remove the product from the market. On average, a benefit-risk reassessment was performed 18.7 years after the product was first marketed. Seventeen products were marketed 5 years or less when the reassessment procedure was completed; six of these products were subsequently removed from the market. CONCLUSIONS: The majority of all benefit-risk reassessments that were performed during the study period did not result in removing the product from the market, but rather, in confirming the positive benefit-risk of the product, conditional to changes to the product's marketing authorisation. About half of all products that were removed from the market during the 2000s had been marketed for more than 20 years. Copyright © 2016 John Wiley & Sons, Ltd.

The effect of exposure misclassification in spontaneous ADR reports on the time to detection of product-specific risks for biologicals: a simulation study.

BACKGROUND AND OBJECTIVE: The availability of accurate product-specific exposure information is essential in the pharmacovigilance of biologicals, because differences in the safety profile may emerge between products containing the same active substance. In spontaneous adverse drug reaction (ADR) reports, drug exposure may, however, be misclassified, that is, attributed to the incorrect product. The aim of this study was to explore the effect of exposure misclassification on the time to detection of product-specific risks in spontaneous reporting systems. METHODS: We used data simulations to explore the effect of exposure misclassification. We simulated an active substance-specific subset of a spontaneous reporting system and used the proportional reporting ratio for signal detection. The effect of exposure misclassification was evaluated in three test cases representing product-specific ADRs that may occur for biologicals and studied in relative terms by varying the model parameters (market share and relative risk). RESULTS: We found that exposure misclassification results in the largest delay in identification of risks that have a weak association (relative risk < 2 or 3) with the product of interest and in situations where the product associated with the unique risk has a large (>50%) market share. The absolute public health impact of exposure misclassification, in terms of cases/time to detection, varied considerably across the test cases. CONCLUSION: Exposure misclassification in ADR reports may result in a delayed detection of product-specific risks, particularly in the detection of weak drug-event associations. Our findings can help inform the future implementation and refinement of product-specific and batch-specific signal detection procedures.

The risk of acute liver injury associated with the use of antibiotics--evaluating robustness of results in the pharmacoepidemiological research on outcomes of therapeutics by a European consortium (PROTECT) project.

PURPOSE: To examine the robustness of findings of case-control studies on the association between acute liver injury (ALI) and antibiotic use in the following different situations: (i) Replication of a protocol in different databases, with different data types, as well as replication in the same database, but performed by a different research team. (ii) Varying algorithms to identify cases, with and without manual case validation. (iii) Different exposure windows for time at risk. METHODS: Five case-control studies in four different databases were performed with a common study protocol as starting point to harmonize study outcome definitions, exposure definitions and statistical analyses. RESULTS: All five studies showed an increased risk of ALI associated with antibiotic use ranging from OR 2.6 (95% CI 1.3-5.4) to 7.7 (95% CI 2.0-29.3). Comparable trends could be observed in the five studies: (i) without manual validation the use of the narrowest definition for ALI showed higher risk estimates, (ii) narrow and broad algorithm definitions followed by manual validation of cases resulted in similar risk estimates, and (iii) the use of a larger window (30 days vs 14 days) to define time at risk led to a decrease in risk estimates. CONCLUSIONS: Reproduction of a study using a predefined protocol in different database settings is feasible, although assumptions had to be made and amendments in the protocol were inevitable. Despite differences, the strength of association was comparable between the studies. In addition, the impact of varying outcome definitions and time windows showed similar trends within the data sources.

Validity of diagnostic codes and laboratory measurements to identify patients with idiopathic acute liver injury in a hospital database.

PURPOSE: The development and validation of algorithms to identify cases of idiopathic acute liver injury (ALI) are essential to facilitate epidemiologic studies on drug-induced liver injury. The aim of this study is to determine the ability of diagnostic codes and laboratory measurements to identify idiopathic ALI cases. METHODS: In this cross-sectional validation study, patients were selected from the hospital-based Utrecht Patient Oriented Database between 2008 and 2010. Patients were identified using (I) algorithms based on ICD-9-CM codes indicative of idiopathic ALI combined with sets of liver enzyme values (ALT > 2× upper limit of normal (ULN); AST > 1ULN + AP > 1ULN + bilirubin > 1ULN; ALT > 3ULN; ALT > 3ULN + bilirubin > 2ULN; ALT > 10ULN) and (II) algorithms based on solely liver enzyme values (ALT > 3ULN + bilirubin > 2ULN; ALT > 10ULN). Hospital medical records were reviewed to confirm final diagnosis. The positive predictive value (PPV) of each algorithm was calculated. RESULTS: A total of 707 cases of ALI were identified. After medical review 194 (27%) patients had confirmed idiopathic ALI. The PPV for (I) algorithms with an ICD-9-CM code as well as abnormal tests ranged from 32% (13/41) to 48% (43/90) with the highest PPV found with ALT > 2ULN. The PPV for (II) algorithms with liver test abnormalities was maximally 26% (150/571). CONCLUSIONS: The algorithm based on ICD-9-CM codes indicative of ALI combined with abnormal liver-related laboratory tests is the most efficient algorithm for identifying idiopathic ALI cases. However, cases were missed using this algorithm, because not all ALI cases had been assigned the relevant diagnostic codes in daily practice.

Understanding inconsistency in the results from observational pharmacoepidemiological studies: the case of antidepressant use and risk of hip/femur fractures.

PURPOSE: Results from observational studies on the same exposure-outcome association may be inconsistent because of variations in methodological factors, clinical factors or health care systems. We evaluated the consistency of results assessing the association between antidepressant use and the risk of hip/femur fractures in three European primary care databases using two different study designs. METHODS: Cohort and nested case control studies were conducted in three European primary care databases (Spanish BIFAP, Dutch Mondriaan and UK THIN) to assess the association between use of antidepressants and hip/femur fracture. A common protocol and statistical analysis plan was applied to harmonize study design and conduct between data sources. RESULTS: Current use of antidepressants was consistently associated with a 1.5 to 2.5-fold increased risk of hip/femur fractures in all data sources with both designs, with estimates for SSRIs generally higher than those for TCAs. In general, risk estimates in Mondriaan, the smallest data source, were higher compared to the other data sources. This difference may be partially explained by an interaction between SSRI and age in Mondriaan. Adjustment for GP-recorded lifestyle factors and matching on general practice had negligible impact on adjusted relative risk estimates. CONCLUSION: We found a consistent increased risk of hip/femur fracture with current use of antidepressants across different databases and different designs. Applying similar pharmacoepidemiological study methods resulted in similar risks for TCA use and some variation for SSRI use. Some of these differences may express real (or natural) variance in the exposure-outcome co-occurrences.

Exposure to benzodiazepines (anxiolytics, hypnotics and related drugs) in seven European electronic healthcare databases: a cross-national descriptive study from the PROTECT-EU Project.

PURPOSE: Studies on drug utilization usually do not allow direct cross-national comparisons because of differences in the respective applied methods. This study aimed to compare time trends in BZDs prescribing by applying a common protocol and analyses plan in seven European electronic healthcare databases. METHODS: Crude and standardized prevalence rates of drug prescribing from 2001-2009 were calculated in databases from Spain, United Kingdon (UK), The Netherlands, Germany and Denmark. Prevalence was stratified by age, sex, BZD type [(using ATC codes), i.e. BZD-anxiolytics BZD-hypnotics, BZD-related drugs and clomethiazole], indication and number of prescription. RESULTS: Crude prevalence rates of BZDs prescribing ranged from 570 to 1700 per 10,000 person-years over the study period. Standardization by age and sex did not substantially change the differences. Standardized prevalence rates increased in the Spanish (+13%) and UK databases (+2% and +8%) over the study period, while they decreased in the Dutch databases (-4% and -22%), the German (-12%) and Danish (-26%) database. Prevalence of anxiolytics outweighed that of hypnotics in the Spanish, Dutch and Bavarian databases, but the reverse was shown in the UK and Danish databases. Prevalence rates consistently increased with age and were two-fold higher in women than in men in all databases. A median of 18% of users received 10 or more prescriptions in 2008. CONCLUSION: Although similar methods were applied, the prevalence of BZD prescribing varied considerably across different populations. Clinical factors related to BZDs and characteristics of the databases may explain these differences.