Bridging differences in outcomes of pharmacoepidemiological studies: design and first results of the PROTECT project

Identifying new drugs associated with pulmonary arterial hypertension: A WHO pharmacovigilance database disproportionality analysis

Since the 1960s, several drugs have been linked to the onset or aggravation of pulmonary arterial hypertension (PAH): dasatinib, some amphetamine-like appetite suppressants (aminorex, fenfluramine, dexfenfluramine, benfluorex) and recreational drugs (methamphetamine). Moreover, in numerous cases, the implication of other drugs with PAH have been suggested, but the precise identification of iatrogenic aetiologies of PAH is challenging given the scarcity of this disease and the potential long latency period between drug intake and PAH onset. In this context, we used the World Health Organization's pharmacovigilance database, VigiBase, to generate new hypotheses about drug associated PAH.

METHODS

We used VigiBase, the largest pharmacovigilance database worldwide to generate disproportionality signals through the Bayesian neural network method. All disproportionality signals were further independently reviewed by experts in pulmonary arterial hypertension, pharmacovigilance and vascular pharmacology and their plausibility ranked according to World Health Organization causality categories.

RESULTS

We included 2184 idiopathic PAH cases, yielding a total of 93 disproportionality signals. Among them, 25 signals were considered very likely, 15 probable, 28 possible and 25 unlikely. Notably, we identified 4 new protein kinases inhibitors (lapatinib, lorlatinib, ponatinib and ruxolitinib), 1 angiogenesis inhibitor (bevacizumab), and several chemotherapeutics (etoposide, trastuzumab), antimetabolites (cytarabine, fludarabine, fluorouracil, gemcitabine) and immunosuppressants (leflunomide, thalidomide, ciclosporin).

CONCLUSION

Such signals represent plausible adverse drug reactions considering the knowledge of iatrogenic PAH, the drugs' biological and pharmacological activity and the characteristics of the reported case. Although confirmatory studies need to be performed, the signals identified may help clinicians envisage an iatrogenic aetiology when faced with a patient who develops PAH.

Quantitative Benefit-Risk Assessment of COVID-19 Vaccines Using the Multi-Criteria Decision Analysis

In the early SARS-CoV-2 (COVID-19) pandemic, four major vaccines were approved despite limited efficacy and safety data through short regulatory review periods. Thus, it is necessary to assess the benefit-risk (BR) profiles of the COVID-19 vaccines. We conducted a quantitative BR assessment for four COVID-19 vaccines (mRNA-based: mRNA-1273 and BNT162b2; viral vector-based: Ad26.COV.2 and ChAdOx1-S) using multi-criteria decision analysis. Three benefit criteria and two risk criteria were considered: preventing COVID-19 infection for (1) adults aged ≥18 years; (2) seniors aged 60 years or older; and (3) severe COVID-19, adverse events (AEs), and serious AEs. Data were retrieved from clinical trials, observational studies, and county-specific AE monitoring reports. Based on the collected data, vaccines were scored for each criterion. 22 professionals weighted each criterion. The overall BR score was calculated using scores and weights. mRNA-1273 was the most preferred vaccine in pre-authorization and BNT162b2 in post-authorization. We found that the mRNA vaccine had a good balance between the benefits and risks. Using this BR assessment, the benefit-risk profile of COVID-19 vaccines can be updated with cumulated data. It will contribute to building evidence for decision making by policy makers and health professionals.

Influenza Vaccination and Risk of Ischemic Stroke: A Population-Based Case-Control Study

BACKGROUND AND OBJECTIVES

To assess the relationship between influenza vaccination in the general population and risk of a first ischemic stroke (IS) during pre-epidemic, epidemic, and postepidemic periods.

METHODS

A nested case-control study was conducted in a Spanish primary care database over 2001-2015. Individuals aged 40-99 years with at least 1 year registry and no history of stroke or cancer were selected to conform the source cohort, from which incident IS cases were identified and classified as cardioembolic or noncardioembolic. Five controls per case were randomly selected, individually matched with cases for exact age, sex, and date of stroke diagnosis (index date). A patient was considered vaccinated when he/she had a recorded influenza vaccination at least 14 days before the index date within the same season. Adjusted odds ratios (aORs) and their respective 95% CIs were computed through a conditional logistic regression. Pneumococcal vaccination was used as a negative control.

RESULTS

From a cohort of 3,757,621 patients, we selected 14,322 incident IS cases (9,542 noncardioembolic and 4,780 cardioembolic) and 71,610 matched controls. Of them, 41.4% and 40.5%, respectively, were vaccinated yielding a crude OR of 1.05 (95% CI 1.01-1.10). Vaccinated patients presented a higher prevalence of vascular risk factors, diseases, and comedication than those nonvaccinated, and after full adjustment, the association of influenza vaccination with IS yielded an aOR of 0.88 (95% CI 0.84-0.92), appearing early (aOR15-30 days 0.79; 95% CI 0.69-0.92) and slightly declining over time (aOR>150 days 0.92; 95% CI 0.87-0.98). A reduced risk of similar magnitude was observed with both types of IS, in the 3 epidemic periods, and in all subgroups analyzed (men, women, individuals younger and older than 65 years of age, and those with intermediate and high vascular risk). By contrast, pneumococcal vaccination was not associated with a reduced risk of IS (aOR 1.08; 95% CI 1.04-1.13).

DISCUSSION

Results are compatible with a moderate protective effect of influenza vaccine on IS appearing early after vaccination. The finding that a reduced risk was also observed in pre-epidemic periods suggests that either the "protection" is not totally linked to prevention of influenza infection or it may be partly explained by unmeasured confounding factors.

Empirical assessment of case-based methods for identification of drugs associated with acute liver injury in the French National Healthcare System database (SNDS)

PURPOSES

Drug induced acute liver injury (ALI) is a frequent cause of liver failure. Case-based designs were empirically assessed and calibrated in the French National claims database (SNDS), aiming to identify the optimum design for drug safety alert generation associated with ALI.

METHODS

All cases of ALI were extracted from SNDS (2009-2014) using specific and sensitive definitions. Positive and negative drug controls were used to compare 196 self-controlled case series (SCCS), case-control (CC), and case-population (CP) design variants, using area under the receiver operating curve (AUC), mean square error (MSE) and coverage probability. Parameters that had major impacts on results were identified through logistic regression.

RESULTS

Using a specific ALI definition, AUCs ranged from 0.78 to 0.94, 0.64 to 0.92 and 0.48 to 0.85, for SCCS, CC and CP, respectively. MSE ranged from 0.12 to 0.40, 0.22 to 0.39 and 1.03 to 5.29, respectively. Variants adjusting for multiple drug use had higher coverage probabilities. Univariate regressions showed that high AUCs were achieved with SCCS using exposed time as the risk window. The top SCCS variant yielded an AUC = 0.93 and MSE = 0.22 and coverage = 86%, with 1/7 negative and 13/18 positive controls presenting significant estimates.

CONCLUSIONS

SCCS adjusting for multiple drugs and using exposed time as the risk window performed best in generating ALI-related drug safety alert and providing estimates of the magnitude of the risk. This approach may be useful for ad-hoc pharmacoepidemiology studies to support regulatory actions.

Approaches for combining primary care electronic health record data from multiple sources: a systematic review of observational studies

OBJECTIVE

To identify observational studies which used data from more than one primary care electronic health record (EHR) database, and summarise key characteristics including: objective and rationale for using multiple data sources; methods used to manage, analyse and (where applicable) combine data; and approaches used to assess and report heterogeneity between data sources.

DESIGN

A systematic review of published studies.

DATA SOURCES

Pubmed and Embase databases were searched using list of named primary care EHR databases; supplementary hand searches of reference list of studies were retained after initial screening.

STUDY SELECTION

Observational studies published between January 2000 and May 2018 were selected, which included at least two different primary care EHR databases.

RESULTS

6054 studies were identified from database and hand searches, and 109 were included in the final review, the majority published between 2014 and 2018. Included studies used 38 different primary care EHR data sources. Forty-seven studies (44%) were descriptive or methodological. Of 62 analytical studies, 22 (36%) presented separate results from each database, with no attempt to combine them; 29 (48%) combined individual patient data in a one-stage meta-analysis and 21 (34%) combined estimates from each database using two-stage meta-analysis. Discussion and exploration of heterogeneity was inconsistent across studies.

CONCLUSIONS

Comparing patterns and trends in different populations, or in different primary care EHR databases from the same populations, is important and a common objective for multi-database studies. When combining results from several databases using meta-analysis, provision of separate results from each database is helpful for interpretation. We found that these were often missing, particularly for studies using one-stage approaches, which also often lacked details of any statistical adjustment for heterogeneity and/or clustering. For two-stage meta-analysis, a clear rationale should be provided for choice of fixed effect and/or random effects or other models.

Differential effects of antidepressant subgroups on risk of acute myocardial infarction: A nested case-control study

The primary objective of this study was to investigate the association between antidepressants use and the risk of acute myocardial infarction (AMI).

METHODS

We conducted a nested case-control study using a primary care database over the period 2002-2015. From a cohort of patients aged 40-99 years, we identified incident AMI cases and randomly selected 5 controls per case, matched to cases for exact age, sex and index date. Exposure to antidepressants were categorised as current, recent, past and nonusers. Adjusted odds ratio (AOR) and 95% confidence interval (CI) were computed using conditional logistic regression to assess the association between the current use of different antidepressants subgroups and AMI as compared to nonuse. Dose and duration effects were explored.

RESULTS

Totals of 24 155 incident AMI cases and 120 775 controls were included. The current use of antidepressants as a group was associated with a reduced risk (AOR = 0.86; 95% CI: 0.81-0.91), but mainly driven by selective serotonin reuptake inhibitors (AOR = 0.86; 95% CI:0.81-0.93). A reduced risk was also observed with trazodone (AOR = 0.76;95% CI: 0.64-0.91), and clomipramine (AOR = 0.62; 95% CI: 0.40-0.96), whereas no significant effect was observed with other antidepressants. A duration-dependent effect was suggested for selective serotonin reuptake inhibitors, trazodone and clomipramine, while there was no clear dose-dependency.

CONCLUSION

This study suggests that current use of antidepressants interfering selectively with the reuptake of serotonin, and those antagonizing the 5-HT_2A receptor, are associated with a decrease in AMI risk and should be the antidepressants of choice in patients at cardiovascular risk.

Empirical assessment of case-based methods for drug safety alert identification in the French National Healthcare System database (SNDS): Methodology of the ALCAPONE project

OBJECTIVES

To introduce the methodology of the ALCAPONE project.

BACKGROUND

The French National Healthcare System Database (SNDS), covering 99% of the French population, provides a potentially valuable opportunity for drug safety alert generation. ALCAPONE aimed to assess empirically in the SNDS case-based designs for alert generation related to four health outcomes of interest.

METHODS

ALCAPONE used a reference set adapted from observational medical outcomes partnership (OMOP) and Exploring and Understanding Adverse Drug Reactions (EU-ADR) project, with four outcomes-acute liver injury (ALI), myocardial infarction (MI), acute kidney injury (AKI), and upper gastrointestinal bleeding (UGIB)-and positive and negative drug controls. ALCAPONE consisted of four main phases: (1) data preparation to fit the OMOP Common Data Model and select the drug controls; (2) detection of the selected controls via three case-based designs: case-population, case-control, and self-controlled case series, including design variants (varying risk window, adjustment strategy, etc.); (3) comparison of design variant performance (area under the ROC curve, mean square error, etc.); and (4) selection of the optimal design variants and their calibration for each outcome.

RESULTS

Over 2009-2014, 5225 cases of ALI, 354 109 MI, 12 633 AKI, and 156 057 UGIB were identified using specific definitions. The number of detectable drugs ranged from 61 for MI to 25 for ALI. Design variants generated more than 50 000 points estimates. Results by outcome will be published in forthcoming papers.

CONCLUSIONS

ALCAPONE has shown the interest of the empirical assessment of pharmacoepidemiological approaches for drug safety alert generation and may encourage other researchers to do the same in other databases.

Clinical Infections by Herpesviruses in Patients Treated with Valproic Acid: A Nested Case-Control Study in the Spanish Primary Care Database, BIFAP

The objective of this study is to evaluate the risk of clinical infections by herpesviruses in patients exposed to valproic acid (VPA). We performed a case-control study nested in a primary cohort selected from the Spanish primary care population-based research database BIFAP (Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria) over the period 2001–2015. The events of interest were those diseases caused by any herpesviruses known to infect humans. For each case, up to 10 controls per case matched by age, gender, and calendar date were randomly selected. A conditional logistic regression was used to compute adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). Current use of VPA was associated with a trend towards a reduced risk of clinical infections by herpesviruses as compared with non-users (OR 0.84; CI 95% 0.7–1.0; p = 0.057). Among current users, a trend to a decreased risk with treatment durations longer than 90 days was also observed. The results show a trend to a reduced risk of clinical infection by herpesviruses in patients exposed to VPA. These results are consistent with those in vitro studies showing that, in cultured cells, VPA can inhibit the production of the infectious progeny of herpesviruses. This study also shows the efficient use of electronic healthcare records for clinical exploratory research studies.

Clopidogrel and Low-Dose Aspirin, Alone or Together, Reduce Risk of Colorectal Cancer

BACKGROUND & AIMS

The antiplatelet effect of low-dose aspirin, via inhibition of cyclooxygenase-1, might contribute to its ability to reduce the risk of colorectal cancer (CRC). Antiplatelet agents with a different mechanism, such as clopidogrel, might have the same effects. We aimed to quantify the effects of low-dose aspirin and clopidogrel on the risk of CRC in a Mediterranean population.

METHODS

We performed a nested case-control study using a primary care database (Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria) in Spain. We collected data, from 2001 through 2014, on 15,491 incident cases of CRC and 60,000 randomly selected individuals (controls), frequency-matched to cases by age, sex, and year. To estimate the association between exposure to different antiplatelet agents and the risk of colorectal cancer, we built multiple logistic regression models and computed the adjusted-odds ratios (AORs) and their respective 95% CIs.

RESULTS

Use of low-dose aspirin was associated with a reduced risk of CRC overall (AOR, 0.83; 95% CI, 0.78-0.89) and in patients receiving treatment for more than 1 year (AOR, 0.79; 95% CI, 0.73-0.85). Use of clopidogrel was associated with a decreased risk of CRC overall (AOR, 0.8; 95% CI, 0.69-0.93) and in patients receiving treatment for more than 1 year (AOR, 0.65; 95% CI, 0.55-0.78). Dual antiplatelet therapy had the same effect as either drug taken as monotherapy. No modification by sex or age was observed.

CONCLUSIONS

In a nested case-control study of a primary care database in Spain, we found clopidogrel use, alone or in combination with low-dose aspirin, to reduce the risk of CRC by 20% to 30%, a magnitude similar to that of low-dose aspirin alone. These data support the concept that inhibiting platelets is an effective strategy for prevention of CRC.

Population-based case-control study: chemoprotection of colorectal cancer with non-aspirin nonsteroidal anti-inflammatory drugs and other drugs for pain control

BACKGROUND

Inflammation and overexpression of cyclooxygenase-2 (COX-2) have been described to play a key role in the progression from nonpathologic intestinal mucosa to colorectal cancer (CRC).

AIMS

To assess the chemoprotective effect of non-aspirin nonsteroidal anti-inflammatory drugs (NA-NSAIDs) under different patterns of use in a Mediterranean population and to explore the potential effect of symptomatic slow-acting drugs for osteoarthritis (SYSADOAs; chondroitin sulfate and glucosamine) and metamizole (or dipyrone), also reported to influence COX-2 activity.

METHODS

We performed a case-control study nested in a cohort extracted from the primary care database, BIFAP. From 2001 to 2014, we included 15 491 incident cases and 60 000 random controls. To estimate the association between the drugs of interest and CRC, we built logistic regression models to compute the adjusted-odds ratios (AOR) and 95% confidence intervals (CI).

RESULTS

NA-NSAIDs use was associated with a reduced risk of CRC (AOR = 0.67; 95% CI: 0.63-0.71) and increased linearly with duration of treatment (p for trend <0.001). The effect diminished upon discontinuation but persisted statistically significant up to 1 year. All individual NA-NSAIDs examined showed a decreased risk. The concomitant use of proton-pump inhibitors (PPI) had no impact on the protective effect of NA-NSAIDs; AOR_{PPI + NSAID}  = 0.64; 0.58-0.71. SYSADOA use was associated with a reduced risk (0.79; 0.69-0.90) but disappeared after the exclusion of NSAID users during the previous 1 or 3 years (0.85; 0.70-1.04 and 1.00; 0.76-1.31 respectively). Metamizole did not show a chemoprotective effect.

CONCLUSIONS

NA-NSAID use is associated with a duration-dependent risk reduction of CRC not shared by SYSADOAs or metamizole.

Validity of hospital ICD-10-GM codes to identify acute liver injury in Germany

PURPOSE

Acute liver injury (ALI) is an important adverse drug reaction. We estimated the positive predictive values (PPVs) of ICD-10-GM codes of ALI used in an international postauthorisation safety study (PASS).

METHODS

Analyses used routine data (2007 to 2016, adults) from a German academic hospital in a cross-sectional design. Two algorithms from the PASS were applied to extract potential cases from the hospital information system: specific end point (A) (discharge diagnosis of liver disease-specific codes) and less specific end point (B) (discharge and outpatient-specific and nonspecific codes suggestive of liver injury). ALI cases were confirmed on the basis of plasma liver enzyme activity elevation. Secondary analysis was performed following exclusion of cases with known cancer, chronic liver, biliary and pancreatic disease, heart failure, and alcohol-related disorders, as applied in the PASS.

RESULTS

On the basis of ICD codes: outcome A, 154 cases (143 with case notes and lab data for case verification); outcome B, 485 cases (357 with case notes and lab data). ALI was confirmed in 71 outcome A cases, PPV of 49.7% (95% confidence interval [CI], 41.2%-58.1%), and 100 outcome B cases, PPV of 28.0% (95% CI, 23.4%-33.0%). Applying exclusion criteria increased PPV (95% CI) to 62.7% (50.0%-74.2%) for outcome A and 45.7% (37.2%-54.3%) for outcome B.

CONCLUSIONS

In safety studies on hepatotoxicity based on routine data using ICD-10-GM discharge codes and when validation of potential cases is not feasible, only the more specific codes should be used to describe ALI, and competing diagnoses for liver injury should be excluded to avoid substantial misclassification.

Lactic acidosis associated with metformin in patients with moderate to severe chronic kidney disease: study protocol for a multicenter population-based case-control study using health databases

BACKGROUND

The use of metformin in patients with type 2 diabetes mellitus has been associated with lactic acidosis. However, the information available in patients with moderate-severe chronic kidney disease is scarce.

METHODS

The ALIMAR-C2 study is a case-control study to assess the association between metformin and lactic acidosis in patients with type 2 diabetes mellitus and moderate-severe chronic kidney disease. The study will be performed with computerized registered electronic health records from eight Spanish hospitals linked to their corresponding primary care health areas from 2010 to 2016, comprising approximately 22.1 million person-years of follow-up. Logistic regression will be used to assess the crude and adjusted risk of lactic acidosis associated with metformin use overall and stratifying by use and dose categories, and chronic kidney disease stage. The overall case fatality rate of lactic acidosis, as well as the case fatality rate stratified by chronic kidney disease stage, will be calculated.

DISCUSSION

The ALIMAR-C2 study will provide useful information about the risk of lactic acidosis in type 2 diabetes mellitus patients with renal impairment using metformin.

Lessons from meta-analyses of randomized clinical trials for analysis of distributed networks of observational databases

Networks of constellations of longitudinal observational databases, often electronic medical records or transactional insurance claims or both, are increasingly being used for studying the effects of medicinal products in real-world use. Such databases are frequently configured as distributed networks. That is, patient-level data are kept behind firewalls and not communicated outside of the data vendor other than in aggregate form. Instead, data are standardized across the network, and queries of the network are executed locally by data partners, and summary results provided to a central research partner(s) for amalgamation, aggregation, and summarization. Such networks can be huge covering years of data on upwards of 100 million patients. Examples of such networks include the FDA Sentinel Network, ASPEN, CNODES, and EU-ADR. As this is a new emerging field, we note in this paper the conceptual similarities and differences between the analysis of distributed networks and the now well-established field of meta-analysis of randomized clinical trials (RCTs). We recommend, wherever appropriate, to apply learnings from meta-analysis to help guide the development of distributed network analyses of longitudinal observational databases.

Evaluation of Electronic Healthcare Databases for Post-Marketing Drug Safety Surveillance and Pharmacoepidemiology in China

INTRODUCTION

Electronic healthcare databases (EHDs) are used increasingly for post-marketing drug safety surveillance and pharmacoepidemiology in Europe and North America. However, few studies have examined the potential of these data sources in China.

METHODS

Three major types of EHDs in China (i.e., a regional community-based database, a national claims database, and an electronic medical records [EMR] database) were selected for evaluation. Forty core variables were derived based on the US Mini-Sentinel (MS) Common Data Model (CDM) as well as the data features in China that would be desirable to support drug safety surveillance. An email survey of these core variables and eight general questions as well as follow-up inquiries on additional variables was conducted. These 40 core variables across the three EHDs and all variables in each EHD along with those in the US MS CDM and Observational Medical Outcomes Partnership (OMOP) CDM were compared for availability and labeled based on specific standards.

RESULTS

All of the EHDs' custodians confirmed their willingness to share their databases with academic institutions after appropriate approval was obtained. The regional community-based database contained 1.19 million people in 2015 with 85% of core variables. Resampled annually nationwide, the national claims database included 5.4 million people in 2014 with 55% of core variables, and the EMR database included 3 million inpatients from 60 hospitals in 2015 with 80% of core variables. Compared with MS CDM or OMOP CDM, the proportion of variables across the three EHDs available or able to be transformed/derived from the original sources are 24-83% or 45-73%, respectively.

CONCLUSIONS

These EHDs provide potential value to post-marketing drug safety surveillance and pharmacoepidemiology in China. Future research is warranted to assess the quality and completeness of these EHDs or additional data sources in China.

Electronic healthcare databases in Europe: descriptive analysis of characteristics and potential for use in medicines regulation

OBJECTIVE

Electronic healthcare databases (EHDs) are useful tools for drug development and safety evaluation but their heterogeneity of structure, validity and access across Europe complicates the conduct of multidatabase studies. In this paper, we provide insight into available EHDs to support regulatory decisions on medicines.

METHODS

EHDs were identified from publicly available information from the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance resources database, textbooks and web-based searches. Databases were selected using criteria related to accessibility, longitudinal dimension, recording of exposure and outcomes, and generalisability. Extracted information was verified with the database owners.

RESULTS

A total of 34 EHDs were selected after applying key criteria relevant for regulatory purposes. The most represented regions were Northern, Central and Western Europe. The most frequent types of data source were electronic medical records (44.1%) and record linkage systems (29.4%). The median number of patients registered in the 34 data sources was 5 million (range 0.07-15 million) while the median time covered by a database was 18.5 years. Paediatric patients were included in 32 databases (94%). Completeness of information on drug exposure was variable. Published validation studies were found for only 17 databases (50%). Some level of access exists for 25 databases (73.5%), and 23 databases (67.6%) can be linked through a personal identification number to other databases with parent-child linkage possible in 7 (21%) databases. Eight databases (23.5%) were already transformed or were in the process of being transformed into a common data model that could facilitate multidatabase studies.

CONCLUSION

A Few European databases meet minimal regulatory requirements and are readily available to be used in a regulatory context. Accessibility and validity information of the included information needs to be improved. This study confirmed the fragmentation, heterogeneity and lack of transparency existing in many European EHDs.

Use of Real-World Data for the Research, Development, and Evaluation of Oncology Precision Medicines

Although randomized controlled trials remain the scientific ideal for determining the efficacy and safety of new treatments, they are sometimes insufficient to address the evidentiary requirements of regulators and payers. This is particularly the case when it comes to precision medicines because trials are often small, deliver incomplete insights into outcomes of most interest to policymakers (eg, overall survival), and may fail to address other complex diagnostic and treatment-related questions. Additional methods, both experimental and observational, are increasingly being used to fill critical evidentiary gaps. A number of modified early- and late-phase trial designs have been proposed to better support earlier biomarker validation, patient identification, and selection for regulatory studies, but there is still a need for confirmatory evidence from real-world data sources. These data are usually provided through observational, postapproval, phase IIIB and IV studies, which rely heavily on registries and other electronic data sets—most notably data from electronic health records. It is, therefore, crucial to understand what ethical, practical, and scientific challenges are raised by the use of electronic health records to generate evidence about precision medicines.

A new risk of bias checklist applicable to randomized trials, observational studies, and systematic reviews was developed and validated to be used for systematic reviews focusing on drug adverse events

OBJECTIVES

The objective of the study was to develop and validate an adequate tool to evaluate the risk of bias of randomized controlled trials, observational studies, and systematic reviews assessing drug adverse events.

STUDY DESIGN AND SETTING

We developed a structured risk of bias checklist applicable to randomized trials, cohort, case-control and nested case-control studies, and systematic reviews focusing on drug safety. Face and content validity was judged by three experienced reviewers. Interrater and intrarater reliability were determined using 20 randomly selected studies, assessed by three other independent reviewers including one performing a 3-week retest.

RESULTS

The developed checklist examines eight domains: study design and objectives, selection bias, attrition, adverse events information bias, other information bias, statistical methods to control confounding, other statistical methods, and conflicts of interest. The total number of questions varied from 10 to 32 depending on the study design. Interrater and intrarater agreements were fair with Kendall's W of 0.70 and 0.74, respectively. Median time to complete the checklist was 8.5 minutes.

CONCLUSION

The developed checklist showed face and content validity and acceptable reliability to assess the risk of bias for studies analyzing drug adverse events. Hence, it might be considered as a novel useful tool for systematic reviews and meta-analyses focusing on drug safety.

The IMI PROTECT project: purpose, organizational structure, and procedures

The Pharmacoepidemiological Research on Outcomes of Therapeutics by a European ConsorTium (PROTECT) initiative was a collaborative European project that sought to address limitations of current methods in the field of pharmacoepidemiology and pharmacovigilance. Initiated in 2009 and ending in 2015, PROTECT was part of the Innovative Medicines Initiative, a joint undertaking by the European Union and pharmaceutical industry. Thirty-five partners including academics, regulators, small and medium enterprises, and European Federation of Pharmaceuticals Industries and Associations companies contributed to PROTECT. Two work packages within PROTECT implemented research examining the extent to which differences in the study design, methodology, and choice of data source can contribute to producing discrepant results from observational studies on drug safety. To evaluate the effect of these differences, the project applied different designs and analytic methodology for six drug-adverse event pairs across several electronic healthcare databases and registries. This papers introduces the organizational structure and procedures of PROTECT, including how drug-adverse event and data sources were selected, study design and analyses documents were developed, and results managed centrally.

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.

Multi-centre, multi-database studies with common protocols: lessons learnt from the IMI PROTECT project

PURPOSE

To assess the impact of a variety of methodological parameters on the association between six drug classes and five key adverse events in multiple databases.

METHODS

The selection of Drug-Adverse Event pairs was based on public health impact, regulatory relevance, and the possibility to study a broad range of methodological issues. Common protocols and data analytical specifications were jointly developed and independently and blindly executed in different databases in Europe with replications in the same and different databases.

RESULTS

The association between antibiotics and acute liver injury, benzodiazepines and hip fracture, antidepressants and hip fracture, inhaled long-acting beta2-agonists and acute myocardial infarction was consistent in direction across multiple designs, databases and methods to control for confounding. Some variation in magnitude of the associations was observed depending on design, exposure and outcome definitions, but none of the differences were statistically significant. The association between anti-epileptics and suicidality was inconsistent across the UK CPRD, Danish National registries and the French PGRx system. Calcium channel blockers were not associated with the risk of cancer in the UK CPRD, and this was consistent across different classes of calcium channel blockers, cumulative durations of use up to >10 years and different types of cancer.

CONCLUSIONS

A network for observational drug effect studies allowing the execution of common protocols in multiple databases was created. Increased consistency of findings across multiple designs and databases in different countries will increase confidence in findings from observational drug research and benefit/risk assessment of medicines.

Methodological comparison of marginal structural model, time-varying Cox regression, and propensity score methods: the example of antidepressant use and the risk of hip fracture

BACKGROUND

Observational studies including time-varying treatments are prone to confounding. We compared time-varying Cox regression analysis, propensity score (PS) methods, and marginal structural models (MSMs) in a study of antidepressant [selective serotonin reuptake inhibitors (SSRIs)] use and the risk of hip fracture.

METHODS

A cohort of patients with a first prescription for antidepressants (SSRI or tricyclic antidepressants) was extracted from the Dutch Mondriaan and Spanish Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria (BIFAP) general practice databases for the period 2001-2009. The net (total) effect of SSRI versus no SSRI on the risk of hip fracture was estimated using time-varying Cox regression, stratification and covariate adjustment using the PS, and MSM. In MSM, censoring was accounted for by inverse probability of censoring weights.

RESULTS

The crude hazard ratio (HR) of SSRI use versus no SSRI use on hip fracture was 1.75 (95%CI: 1.12, 2.72) in Mondriaan and 2.09 (1.89, 2.32) in BIFAP. After confounding adjustment using time-varying Cox regression, stratification, and covariate adjustment using the PS, HRs increased in Mondriaan [2.59 (1.63, 4.12), 2.64 (1.63, 4.25), and 2.82 (1.63, 4.25), respectively] and decreased in BIFAP [1.56 (1.40, 1.73), 1.54 (1.39, 1.71), and 1.61 (1.45, 1.78), respectively]. MSMs with stabilized weights yielded HR 2.15 (1.30, 3.55) in Mondriaan and 1.63 (1.28, 2.07) in BIFAP when accounting for censoring and 2.13 (1.32, 3.45) in Mondriaan and 1.66 (1.30, 2.12) in BIFAP without accounting for censoring.

CONCLUSIONS

In this empirical study, differences between the different methods to control for time-dependent confounding were small. The observed differences in treatment effect estimates between the databases are likely attributable to different confounding information in the datasets, illustrating that adequate information on (time-varying) confounding is crucial to prevent bias.

Comparability of the age and sex distribution of the UK Clinical Practice Research Datalink and the total Dutch population

PURPOSE

The UK Clinical Practice Research Datalink (CPRD) is increasingly being used by Dutch researchers in epidemiology and pharmacoepidemiology. It is however unclear if the UK CPRD is representative of the Dutch population and whether study results would apply to the Dutch population. Therefore, as first step, our objective was to compare the age and sex distribution of the CPRD with the total Dutch population.

METHODS

As a measure of representativeness, the age and sex distribution of the UK CPRD were visually and numerically compared with Dutch census data from the StatLine database of the Dutch National Bureau of Statistics in 2011.

RESULTS

The age distribution of men and women in the CPRD population was comparable to the Dutch male and female population. Differences of more than 10% only occurred in older age categories (75+ in men and 80+ in women).

CONCLUSIONS

Results from observational studies that have used CPRD data are applicable to the Dutch population, and a useful resource for decision making in the Netherlands. Nevertheless, differences in drug exposure likelihood between countries should be kept in mind, as these could still cause variations in the actual population studied, thereby decreasing its generalizability. Copyright © 2016 John Wiley & Sons, Ltd.

Scaling up health knowledge at European level requires sharing integrated data: an approach for collection of database specification

Computerized health care databases have been widely described as an excellent opportunity for research. The availability of "big data" has brought about a wave of innovation in projects when conducting health services research. Most of the available secondary data sources are restricted to the geographical scope of a given country and present heterogeneous structure and content. Under the umbrella of the European Innovation Partnership on Active and Healthy Ageing, collaborative work conducted by the partners of the group on "adherence to prescription and medical plans" identified the use of observational and large-population databases to monitor medication-taking behavior in the elderly. This article describes the methodology used to gather the information from available databases among the Adherence Action Group partners with the aim of improving data sharing on a European level. A total of six databases belonging to three different European countries (Spain, Republic of Ireland, and Italy) were included in the analysis. Preliminary results suggest that there are some similarities. However, these results should be applied in different contexts and European countries, supporting the idea that large European studies should be designed in order to get the most of already available databases.

A methodological comparison of two European primary care databases and replication in a US claims database: inhaled long-acting beta-2-agonists and the risk of acute myocardial infarction

PURPOSE

Results from observational studies on inhaled long-acting beta-2-agonists (LABA) and acute myocardial infarction (AMI) risk are conflicting, presumably due to variation in methodology. We aimed to evaluate the impact of applying a common study protocol on consistency of results in three databases.

METHODS

In the primary analysis, we included patients from two GP databases (Dutch-Mondriaan, UK-CPRD GOLD) with a diagnosis of asthma and/or COPD and at least one inhaled LABA or a "non-LABA inhaled bronchodilator medication" (short-acting beta-2-agonist or short-/long-acting muscarinic antagonist) prescription between 2002 and 2009. A claims database (USA-Clinformatics) was used for replication. LABA use was divided into current, recent (first 91 days following the end of a treatment episode), and past use (after more than 91 days following the end of a treatment episode). Adjusted hazard ratios (AMI-aHR) and 95 % confidence intervals (95 % CI) were estimated using time-dependent multivariable Cox regression models stratified by recorded diagnoses (asthma, COPD, or both asthma and COPD).

RESULTS

For asthma or COPD patients, no statistically significant AMI-aHRs (age- and sex-adjusted) were found in the primary analysis. For patients with both diagnoses, a decreased AMI-aHR was found for current vs. recent LABA use in the CPRD GOLD (0.78; 95 % CI 0.68-0.90) and in Mondriaan (0.55; 95 % CI 0.28-1.08), too. The replication study yielded similar results. Adjusting for concomitant medication use and comorbidities, in addition to age and sex, had little impact on the results.

CONCLUSIONS

By using a common protocol, we observed similar results in the primary analysis performed in two GP databases and in the replication study in a claims database. Regarding differences between databases, a common protocol facilitates interpreting results due to minimized methodological variations. However, results of multinational comparative observational studies might be affected by bias not fully addressed by a common protocol.

Electronic Health Data for Postmarket Surveillance: A Vision Not Realized

What has been learned about electronic health data as a primary data source for regulatory decisions regarding the harms of drugs? Observational studies with electronic health data for postmarket risk assessment can now be conducted in Europe and the US in patient populations numbering in the tens of millions compared with a few hundred patients in a typical clinical trial. With standard protocols, results can be obtained in a few months; however, extensive research published by scores of investigators has illuminated the many obstacles that prevent obtaining robust, reproducible results that are reliable enough to be a primary source for drug safety decisions involving the health and safety of millions of patients. The most widely used terminology for coding patient interactions with medical providers for payment has proved ill-suited to identifying the adverse effects of drugs. Directly conflicting results were reported in otherwise similar patient health databases, even using identical event definitions and research methods. Evaluation of some accepted statistical methods revealed systematic bias, while others appeared to be unreliable. When electronic health data studies detected no drug risk, there were no robust and accepted standards to judge whether the drug was unlikely to cause the adverse effect or whether the study was incapable of detecting it. Substantial investment and careful thinking is needed to improve the reliability of risk assessments based on electronic health data, and current limitations need to be fully understood.

Systematic Review and Meta-Analysis: Macrolides- and Amoxicillin/Clavulanate-induced Acute Liver Injury

Antibacterials are frequently associated with idiosyncratic drug-induced liver injury (DILI). The objective of this study was to estimate the risk of macrolides and amoxicillin/clavulanate (AMC) on DILI. We conducted a systematic review (SR) and meta-analysis (MA) with studies retrieved from PubMed, Cochrane Library Plus, Web of Knowledge, clinicaltrials.gov, Livertox and Toxline (1980-2014). We searched for macrolides, AMC and MeSH and synonym terms for DILI. We included all study designs except case reports/series, all population ages and studies with a placebo/non-user comparator. We summarized the evidence with a random-effects MA. Quality of the studies was appraised with a checklist developed for SR of adverse effects. Heterogeneity and publication bias were assessed with different exploratory tools. We finally included 10 (two randomized clinical trials, six case-control, one cohort and one case-population studies) and 9 (case-population excluded) articles in the SR and MA, respectively. The overall summary relative risk of DILI for macrolides was 2.85 [95% confidence interval (CI) 1.81-4.47], p < 0.0001, I(2) = 57%. Three studies were perceived to be missing in the area of low statistical significance. Year of study and selected exposure window partly explained the variability between studies. For AMC, the risk of DILI was 9.38 (95% CI 0.65-135.41) p = 0.3, I2 = 95%. In conclusion, although spontaneous reports and case series have long established an association between macrolides and AMC with acute liver injury, these SR and MA have assessed the magnitude of this association. The low incidence of DILI and the therapeutic place of these antibiotics might tilt the balance in favour of their benefits.

Calcium channel blockers and cancer: a risk analysis using the UK Clinical Practice Research Datalink (CPRD)

OBJECTIVE

The evidence of an association between calcium channel blockers (CCBs) and cancer is conflicting. The objective of the present study was to evaluate the risk of cancer (all, breast, prostate and colon cancers) in association with exposure to CCB.

METHODS

This is a population-based cohort study in patients exposed to CCBs from across the UK, using two comparison cohorts: (1) patients with no exposure to CCB (non-CCB) matched on age and gender and (2) unmatched patients unexposed to CCB and at least one other antihypertensive (AHT) prescription. Cancer incidence rates computed in the exposed and the two unexposed groups were compared using HRs and 95% CIs obtained from multivariate Cox regression analyses.

RESULTS

Overall, 150,750, 557,931 and 156,966 patients were included, respectively, in the CCB, non-CCB and AHT cohorts. Crude cancer incidence rates per 1000 person-years were 16.51, 15.75 and 10.62 for the three cohorts, respectively. Adjusted HRs (CI) for all cancers comparing CCB, non-CCB and AHT cohorts were 0.88 (0.86 to 0.89) and 1.01 (0.98 to 1.04), respectively. Compared to the AHT cohort, adjusted HRs (CI) for breast, prostate and colon cancer for the CCB cohort were 0.95 (0.87 to 1.04), 1.07 (0.98 to 1.16) and 0.89 (0.81 to 0.98), respectively. Analyses by duration of exposure to CCB did not show excess risk.

CONCLUSIONS

This large population-based study provides strong evidence that CCB use is not associated with an increased risk of cancer. The analyses yielded robust results across all types of cancer and different durations of exposure to CCBs.

Designing and incorporating a real world data approach to international drug development and use: what the UK offers

Assessments of the safety, efficacy and appropriate use of new medicines lie at the heart of treatment development and subsequent adoption in clinical practice. Highly controlled randomised clinical trials routinely inform decisions on the approval, coverage and use of a medicine. Researchers and decision makers have become increasingly aware that these experimental data alone are insufficient to address those decisions fully. Real world data recorded from routine healthcare delivery by healthcare professionals and patients help provide a more complete picture of care. The UK, with its connectivity and rich longitudinal patient records, accumulated research and informatics experience and National Health Service, provides an exemplar of how real world data address a wide range of challenges across drug development.

Sales of macrolides, lincosamides, streptogramins, and amoxicillin/clavulanate in the in- and outpatient setting in 10 European countries, 2007-2010

Monitoring the use of antibiotics is relevant due to the public health impact of microbial resistance, adverse effects, and costs. We present data on the consumption of macrolides, lincosamides, streptogramins and amoxicillin/clavulanate (AMC) between 2007 and 2010 in the in-and outpatient healthcare setting in 10 European countries provided by IMS Health. Antibiotics were classified according to the anatomical therapeutic chemical classification and consumption was expressed in defined daily doses/1000 inhabitants/day (DIDs). We analysed the number of prescriptions by diagnostic codes between 2008 and 2010, based on the International Classification of Diseases, 10th revision (ICD-10). These ICD-10 codes were grouped into four main categories: respiratory infections, genitourinary infections, other infections and other diagnoses. In 2010, the consumption of macrolides and lincosamides ranged from 0.45 DIDs (Sweden) to 5.46 DIDs (Italy), and from 0.04 DIDs (Denmark) to 1.00 DID (Germany), respectively. Streptogramins were available in France, Germany, Italy, Norway, Spain and United Kingdom with a consumption of <0.001 DID exclusively in the hospital setting. The consumption of AMC ranged from <0.001 DIDs (Norway) to 11.67 DIDs (Spain). During the study period, the consumption of macrolides decreased, the consumption of AMC increased in most of European countries, and lincosamides varied very slightly. Macrolides and AMC were mainly prescribed for respiratory infections in all countries but United Kingdom, where most of the prescriptions were assigned to diagnostic codes not clearly related with an infection. Lincosamides were prescribed for the respiratory infections and other infections groups. There was a wide inter-country variability in the percentage of the prescriptions assigned to each of the diagnostic categories. The inter-country differences in the consumption of these antibiotics and their prescription by diagnostic categories point to an inappropriate use of antibiotics.

The risk of acute liver injury among users of antibiotic medications: a comparison of case-only studies

PURPOSE

The aims of this study were two-fold: (i) to investigate the effect of exposure to antibiotic agents on the risk of acute liver injury using a self-controlled case series and case-crossover study and (ii) to compare the results between the case-only studies.

METHODS

For the self-controlled case series study relative incidence ratios (IRR) were calculated by dividing the rate of acute liver injury experienced during patients' periods of exposure to antibiotics to patients' rate of events during non-exposed time using conditional Poisson regression. For the case-crossover analysis we calculated Odds Ratios (OR) using conditional logistic regression by comparing exposure during 14- and 30-day risk windows with exposure during control moments.

RESULTS

Using the self-controlled case series approach, the IRR was highest during the first 7 days after receipt of a prescription (10.01, 95% CI 6.59-15.18). Omitting post-exposure washout periods lowered the IRR to 7.2. The highest estimate in the case-crossover analysis was found when two 30-day control periods 1 year prior to the 30-day ALI risk period were retained in the analysis: OR = 6.5 (95% CI, 3.95-10.71). The lowest estimate was found when exposure in the 14-day risk period was compared to exposure in four consecutive 14-day control periods immediately prior to the risk period (OR = 3.05, 95% CI, 2.06-4.53).

CONCLUSION

An increased relative risk of acute liver injury was consistently observed using both self-controlled case series and case-crossover designs. Case-only designs can be used as a viable alternative study design to study the risk of acute liver injury, albeit with some limitations.

Do case-only designs yield consistent results across design and different databases? A case study of hip fractures and benzodiazepines

Background

The case‐crossover (CXO) and self‐controlled case series (SCCS) designs are increasingly used in pharmacoepidemiology. In both, relative risk estimates are obtained within persons, implicitly controlling for time‐fixed confounding variables.

Objectives

To examine the consistency of relative risk estimates of hip/femur fractures (HFF) associated with the use of benzodiazepines (BZD) across case‐only designs in two databases (DBs), when a common protocol was applied.

Methods

CXO and SCCS studies were conducted in BIFAP (Spain) and CPRD (UK). Exposure to BZD was divided into non‐use, current, recent and past use. For CXO, odds ratios (OR; 95%CI) of current use versus non‐use/past were estimated using conditional logistic regression adjusted for co‐medications (AOR). For the SCCS, conditional Poisson regression was used to estimate incidence rate ratios (IRR; 95%CI) of current use versus non/past‐use, adjusted for age. To investigate possible event‐exposure dependence the relative risk in the 30 days prior to first BZD exposure was also evaluated.

Results

In the CXO current use of BZD was associated with an increased risk of HFF in both DBs, AOR_BIFAP = 1.47 (1.29–1.67) and AOR_CPRD = 1.55 (1.41–1.70). In the SCCS, IRRs for current exposure was 0.79 (0.72–0.86) in BIFAP and 1.21 (1.13–1.30) in CPRD. However, when we considered separately the 30‐day pre‐exposure period, the IRR for current period was 1.43 (1.31–1.57) in BIFAP and 1.37 (1.27–1.47) in CPRD.

Conclusions

CXO designs yielded consistent results across DBs, while initial SCCS analyses did not. Accounting for event‐exposure dependence, estimates derived from SCCS were more consistent across DBs and designs. © 2015 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.

Hip/femur fractures associated with the use of benzodiazepines (anxiolytics, hypnotics and related drugs): a methodological approach to assess consistencies across databases from the PROTECT-EU project

BACKGROUND

Results from observational studies may be inconsistent because of variations in methodological and clinical factors that may be intrinsically related to the database (DB) where the study is performed.

OBJECTIVES

The objectives of this paper were to evaluate the impact of applying a common study protocol to study benzodiazepines (BZDs) (anxiolytics, hypnotics, and related drugs) and the risk of hip/femur fracture (HFF) across three European primary care DBs and to investigate any resulting discrepancies.

METHODS

To measure the risk of HFF among adult users of BZDs during 2001-2009, three cohort and nested case control (NCC) studies were performed in Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria (BIFAP) (Spain), Clinical Practice Research Datalink (CPRD) (UK), and Mondriaan (The Netherlands). Four different models (A-D) with increasing levels of adjustment were analyzed. The risk according to duration and type of BZD was also explored. Adjusted hazard ratios (cohort), odds ratios (NCC), and their 95% confidence intervals were estimated.

RESULTS

Adjusted hazard ratios (Model C) were 1.34 (1.23-1.47) in BIFAP, 1.66 (1.54-1.78) in CPRD, and 2.22 (1.55-3.29) in Mondriaan in cohort studies. Adjusted odds ratios (Model C) were 1.28 (1.16-1.42) in BIFAP, 1.60 (1.49-1.72) in CPRD, and 1.48 (0.89-2.48) in Mondriaan in NCC studies. A short-term effect was suggested in Mondriaan, but not in CPRD or BIFAP. All DBs showed an increased risk with the concomitant use of anxiolytic and hypnotic drugs.

CONCLUSIONS

Applying similar study methods to different populations and DBs showed an increased risk of HFF in BZDs users but differed in the magnitude of the risk, which may be because of inherent differences between DBs.

[Benefits of large healthcare databases for drug risk research]

Large electronic healthcare databases have become an important worldwide data resource for drug safety research after approval. Signal generation methods and drug safety studies based on these data facilitate the prospective monitoring of drug safety after approval, as has been recently required by EU law and the German Medicines Act. Despite its large size, a single healthcare database may include insufficient patients for the study of a very small number of drug-exposed patients or the investigation of very rare drug risks. For that reason, in the United States, efforts have been made to work on models that provide the linkage of data from different electronic healthcare databases for monitoring the safety of medicines after authorization in (i) the Sentinel Initiative and (ii) the Observational Medical Outcomes Partnership (OMOP). In July 2014, the pilot project Mini-Sentinel included a total of 178 million people from 18 different US databases. The merging of the data is based on a distributed data network with a common data model. In the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance (ENCEPP) there has been no comparable merging of data from different databases; however, first experiences have been gained in various EU drug safety projects. In Germany, the data of the statutory health insurance providers constitute the most important resource for establishing a large healthcare database. Their use for this purpose has so far been severely restricted by the Code of Social Law (Section 75, Book 10). Therefore, a reform of this section is absolutely necessary.

A systematic review of medication exposure assessment in prospective cohort studies of community dwelling older australians

Introduction

It is not known to what extent medication use has been comprehensively assessed in prospective cohort studies of older Australians. Understanding the varying methods to assess medication use is necessary to establish comparability and to understand the opportunities for pharmacoepidemiological analysis. The objective of this review was to compare and contrast how medication-related data have been collected in prospective cohorts of community-dwelling older Australians.

Methods

MEDLINE and EMBASE (1990–2014) were systematically searched to identify prospective cohorts of ≥1000 older participants that commenced recruitment after 1990. The data collection tools used to assess medication use in each cohort were independently examined by two investigators using a structured approach.

Results

Thirteen eligible cohorts were included. Baseline medication use was assessed in participant self-completed surveys (n = 3), by an investigator inspecting medications brought to a clinic interview (n = 7), and by interviewing participants in their home (n = 3). Five cohorts sought participant consent to access administrative claims data. Six cohorts used multiple methods to assess medication use across one or more study waves. All cohorts assessed medication use at baseline and 12 cohorts in follow-up waves. Twelve cohorts recorded prescription medications by trade or generic name; 12 cohorts recorded medication strength; and 9 recorded the daily medication dose in at least one wave of the cohort. Seven cohorts asked participants about their “current” medication use without providing a definition of “current”; and nine cohorts asked participants to report medication use over recall periods ranging from 1-week to 3-months in at least one wave of the cohort. Sixty-five original publications, that reported the prevalence or outcomes of medication use, in the 13 cohorts were identified (median = 3, range 1–21).

Conclusion

There has been considerable variability in the assessment of medication use within and between cohorts. This may limit the comparability of medication data collected in these cohorts.

Time trends of period prevalence rates of patients with inhaled long-acting beta-2-agonists-containing prescriptions: a European comparative database study

BACKGROUND

Inhaled, long-acting beta-2-adrenoceptor agonists (LABA) have well-established roles in asthma and/or COPD treatment. Drug utilisation patterns for LABA have been described, but few studies have directly compared LABA use in different countries. We aimed to compare the prevalence of LABA-containing prescriptions in five European countries using a standardised methodology.

METHODS

A common study protocol was applied to seven European healthcare record databases (Denmark, Germany, Spain, the Netherlands (2), and the UK (2)) to calculate crude and age- and sex-standardised annual period prevalence rates (PPRs) of LABA-containing prescriptions from 2002-2009. Annual PPRs were stratified by sex, age, and indication (asthma, COPD, asthma and COPD).

RESULTS

From 2002-2009, age- and sex-standardised PPRs of patients with LABA-containing medications increased in all databases (58.2%-185.1%). Highest PPRs were found in men ≥ 80 years old and women 70-79 years old. Regarding the three indications, the highest age- and sex-standardised PPRs in all databases were found in patients with "asthma and COPD" but with large inter-country variation. In those with asthma or COPD, lower PPRs and smaller inter-country variations were found. For all three indications, PPRs for LABA-containing prescriptions increased with age.

CONCLUSIONS

Using a standardised protocol that allowed direct inter-country comparisons, we found highest rates of LABA-containing prescriptions in elderly patients and distinct differences in the increased utilisation of LABA-containing prescriptions within the study period throughout the five European countries.

Seasonal changes in prescribing of long-acting beta-2-agonists-containing drugs

BACKGROUND

For patients with asthma, COPD, or asthma-COPD overlap syndrome (ACOS), inter-country comparisons of seasonal changes in drug prescriptions are scarce or missing. Hence, we aimed to compare seasonal changes in prescription rates of long-acting beta-2-agonist (LABA) in four European countries.

METHODS

A common study protocol was applied to six health care databases (Germany, Spain, the Netherlands (2), and the UK (2)) to calculate age- and sex-standardized point prevalence rates (PPRs) of LABA-containing prescriptions by the 1st of March, June, September, and December of each year during the study period 2002-2009. Seasonal variation of PPRs was quantified using seasonal indexes (SIs; based on the ratio-to-moving-average-method) and SIs averaged over the study period (aSI) stratified by sex, age, and indication (asthma, COPD, or ACOS).

RESULTS

There was a moderate seasonal change in LABA-containing prescriptions which was more pronounced in asthma or COPD patients compared to ACOS patients. For asthma and ACOS patients, highest seasonal variation was found for patients living in Spain (aSI: 87.3-110.7, aSI: 93.2-103.1) whereas for COPD highest seasonal variation was revealed for the NPCRD database (the Netherlands) (aSI: 92.2-105.6). Regarding age and sex, highest seasonal variation was found in Spanish boys under 10 years of age having a diagnosis of asthma.

CONCLUSIONS

By applying a common analysis in six databases, we could observe moderate overall seasonal changes in LABA-containing prescription rates in patients with asthma, COPD, or ACOS.

Ascertainment of acute liver injury in two European primary care databases

PURPOSE

The purpose of this study was to ascertain acute liver injury (ALI) in primary care databases using different computer algorithms. The aim of this investigation was to study and compare the incidence of ALI in different primary care databases and using different definitions of ALI.

METHODS

The Clinical Practice Research Datalink (CPRD) in UK and the Spanish "Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria" (BIFAP) were used. Both are primary care databases from which we selected individuals of all ages registered between January 2004 and December 2009. We developed two case definitions of idiopathic ALI using computer algorithms: (i) restrictive definition (definite cases) and (ii) broad definition (definite and probable cases). Patients presenting prior liver conditions were excluded. Manual review of potential cases was performed to confirm diagnosis, in a sample in CPRD (21%) and all potential cases in BIFAP. Incidence rates of ALI by age, sex and calendar year were calculated.

RESULTS

In BIFAP, all cases considered definite after manual review had been detected with the computer algorithm as potential cases, and none came from the non-cases group. The restrictive definition of ALI had a low sensitivity but a very high specificity (95% in BIFAP) and showed higher rates of agreement between computer search and manual review compared to the broad definition. Higher incidence rates of definite ALI in 2008 were observed in BIFAP (3.01 (95% confidence interval (CI) 2.13-4.25) per 100,000 person-years than CPRD (1.35 (95% CI 1.03-1.78)).

CONCLUSIONS

This study shows that it is feasible to identify ALI cases if restrictive selection criteria are used and the possibility to review additional information to rule out differential diagnoses. Our results confirm that idiopathic ALI is a very rare disease in the general population. Finally, the construction of a standard definition with predefined criteria facilitates the timely comparison across databases.

Incidence rates and trends of hip/femur fractures in five European countries: comparison using e-healthcare records databases

Hip fractures represent a major public health challenge worldwide. Multinational studies using a common methodology are scarce. We aimed to estimate the incidence rates (IRs) and trends of hip/femur fractures over the period 2003-2009 in five European countries. The study was performed using seven electronic health-care records databases (DBs) from Denmark, The Netherlands, Germany, Spain, and the United Kingdom, based on the same protocol. Yearly IRs of hip/femur fractures were calculated for the general population and for those aged ≥50 years. Trends over time were evaluated using linear regression analysis for both crude and standardized IRs. Sex- and age-standardized IRs for the UK, Netherlands, and Spanish DBs varied from 9 to 11 per 10,000 person-years for the general population and from 22 to 26 for those ≥50 years old; the German DB showed slightly higher IRs (about 13 and 30, respectively), whereas the Danish DB yielded IRs twofold higher (19 and 52, respectively). IRs increased exponentially with age in both sexes. The ratio of females to males was ≥2 for patients aged ≥70-79 years in most DBs. Statistically significant trends over time were only shown for the UK DB (CPRD) (+0.7% per year, P < 0.01) and the Danish DB (-1.4% per year, P < 0.01). IRs of hip/femur fractures varied greatly across European countries. With the exception of Denmark, no decreasing trend was observed over the study period.

Antidepressant prescribing in five European countries: application of common definitions to assess the prevalence, clinical observations, and methodological implications

PURPOSE

Drug utilization studies have applied different methods to various data types to describe medication use, which hampers comparisons across populations. The aim of this study was to describe the time trends in antidepressant prescribing in the last decade and the variation in the prevalence, calculated in a uniform manner, in seven European electronic healthcare databases.

METHODS

Annual prevalence per 10,000 person-years (PYs) was calculated for 2001-2009 in databases from Spain, Germany, Denmark, the United Kingdom (UK), and the Netherlands. Prevalence data were stratified according to age, sex, antidepressant type (selective serotonin re-uptake inhibitors [SSRIs] or tricyclic antidepressants [TCAs]) and major indications.

RESULTS

The age- and sex-standardized prevalence was lowest in the two Dutch (391 and 429 users per 10,000 PYs) and highest in the two UK (913 and 936 users per 10,000 PYs) populations in 2008. The prevalence in the Danish, German, and Spanish populations was 637, 618, and 644 users per 10,000 PY respectively. Antidepressants were prescribed most often in 20- to 60-year-olds in the two UK populations compared with the others. SSRIs were prescribed more often than TCAs in all except the German population. In the majority of countries we observed an increasing trend of antidepressant prescribing over time. Two different methods identifying recorded indications yielded different ranges of proportions of patients recorded with the specific indication (15-57% and 39-69% for depression respectively).

CONCLUSION

Despite applying uniform methods, variations in the prevalence of antidepressant prescribing were obvious in the different populations. Database characteristics and clinical factors may both explain these variations.

A compilation of research working groups on drug utilisation across Europe

Background

The assessment of the benefit-risk of medicines needs careful consideration concerning their patterns of utilization. Systems for the monitoring of medicines consumption have been established in many European countries, and several international groups have identified and described them. No other compilation of European working groups has been published.

As part of the PROTECT project, as a first step in searching for European data sources on the consumption of five selected groups of medicines, we aimed to identify and describe the main characteristics of the existing collaborative European working groups.

Findings

Google and bibliographic searches (PubMed) of articles containing information on databases and other sources of drug consumption data were conducted. For each working group the main characteristics were recorded.

Nineteen selected groups were identified, focusing on: a) general drug utilisation (DU) research (EuroDURG, CNC, ISPE’S SIG-DUR, EURO-MED-STAT, PIPERSKA Group, NorPEN, ENCePP, DURQUIM), b) specific DU research: b.1) antimicrobial drugs (ARPAC, ESAC, ARPEC, ESGAP, HAPPY AUDIT), b.2) cardiovascular disease (ARITMO, EUROASPIRE), b.3) paediatrics (TEDDY), and b.4) mental health/central nervous system effects (ESEMeD, DRUID, TUPP/EUPoMMe). Information on their aims, methods and activities is presented.

Conclusions

We assembled and updated information on European working groups in DU research and in the utilisation of five selected groups of drugs for the PROTECT project. This information should be useful for academic researchers, regulatory and health authorities, and pharmaceutical companies conducting and interpreting post-authorisation and safety studies. European health authorities should encourage national research and collaborations in this important field for public health.