Antoine Pariente

Benzodiazepine use and risk of Alzheimer’s disease: case-control study

Objectives To investigate the relation between the risk of Alzheimer’s disease and exposure to benzodiazepines started at least five years before, considering both the dose-response relation and prodromes (anxiety, depression, insomnia) possibly linked with treatment. Design Case-control study. Setting The Quebec health insurance program database (RAMQ). Participants 1796 people with a first diagnosis of Alzheimer’s disease and followed up for at least six years before were matched with 7184 controls on sex, age group, and duration of follow-up. Both groups were randomly sampled from older people (age >66) living in the community in 2000-09. Main outcome measure The association between Alzheimer’s disease and benzodiazepine use started at least five years before diagnosis was assessed by using multivariable conditional logistic regression. Ever exposure to benzodiazepines was first considered and then categorised according to the cumulative dose expressed as prescribed daily doses (1-90, 91-180, >180) and the drug elimination half life. Results Benzodiazepine ever use was associated with an increased risk of Alzheimer’s disease (adjusted odds ratio 1.51, 95% confidence interval 1.36 to 1.69; further adjustment on anxiety, depression, and insomnia did not markedly alter this result: 1.43, 1.28 to 1.60). No association was found for a cumulative dose <91 prescribed daily doses. The strength of association increased with exposure density (1.32 (1.01 to 1.74) for 91-180 prescribed daily doses and 1.84 (1.62 to 2.08) for >180 prescribed daily doses) and with the drug half life (1.43 (1.27 to 1.61) for short acting drugs and 1.70 (1.46 to 1.98) for long acting ones). Conclusion Benzodiazepine use is associated with an increased risk of Alzheimer’s disease. The stronger association observed for long term exposures reinforces the suspicion of a possible direct association, even if benzodiazepine use might also be an early marker of a condition associated with an increased risk of dementia. Unwarranted long term use of these drugs should be considered as a public health concern.

Data mining on electronic health record databases for signal detection in pharmacovigilance: which events to monitor?

Data mining on electronic health records (EHRs) has emerged as a promising complementary method for post‐marketing drug safety surveillance. The EU‐ADR project, funded by the European Commission, is developing techniques that allow mining of EHRs for adverse drug events across different countries in Europe. Since mining on all possible events was considered to unduly increase the number of spurious signals, we wanted to create a ranked list of high‐priority events.

Increased risk of narcolepsy in children and adults after pandemic H1N1 vaccination in France

An increased incidence of narcolepsy in children was detected in Scandinavian countries where pandemic H1N1 influenza ASO3-adjuvanted vaccine was used. A campaign of vaccination against pandemic H1N1 influenza was implemented in France using both ASO3-adjuvanted and non-adjuvanted vaccines. As part of a study considering all-type narcolepsy, we investigated the association between H1N1 vaccination and narcolepsy with cataplexy in children and adults compared with matched controls; and compared the phenotype of narcolepsy with cataplexy according to exposure to the H1N1 vaccination. Patients with narcolepsy-cataplexy were included from 14 expert centres in France. Date of diagnosis constituted the index date. Validation of cases was performed by independent experts using the Brighton collaboration criteria. Up to four controls were individually matched to cases according to age, gender and geographic location. A structured telephone interview was performed to collect information on medical history, past infections and vaccinations. Eighty-five cases with narcolepsy-cataplexy were included; 23 being further excluded regarding eligibility criteria. Of the 62 eligible cases, 59 (64% males, 57.6% children) could be matched with 135 control subjects. H1N1 vaccination was associated with narcolepsy-cataplexy with an odds ratio of 6.5 (2.1-19.9) in subjects aged<18 years, and 4.7 (1.6-13.9) in those aged 18 and over. Sensitivity analyses considering date of referral for diagnosis or the date of onset of symptoms as the index date gave similar results, as did analyses focusing only on exposure to ASO3-adjuvanted vaccine. Slight differences were found when comparing cases with narcolepsy-cataplexy exposed to H1N1 vaccination (n=32; mostly AS03-adjuvanted vaccine, n=28) to non-exposed cases (n=30), including shorter delay of diagnosis and a higher number of sleep onset rapid eye movement periods for exposed cases. No difference was found regarding history of infections. In this sub-analysis, H1N1 vaccination was strongly associated with an increased risk of narcolepsy-cataplexy in both children and adults in France. Even if, as in every observational study, the possibility that some biases participated in the association cannot be completely ruled out, the associations appeared robust to sensitivity analyses, and a specific analysis focusing on ASO3-adjuvanted vaccine found similar increase.

Benzodiazepines and Injurious Falls in Community Dwelling Elders

BackgroundBenzodiazepines are frequently used medications in the elderly, in whom they are associated with an increased risk of falling, with sometimes dire consequences.ObjectiveTo estimate the impact of benzodiazepine-associated injurious falls in a population of elderly persons.MethodA nested case-control study was conducted using data collected during 10 years of follow-up of the French PAQUID (Personnes Agées QUID) community-based cohort. The main outcome measure was the occurrence of an injurious fall, which was defined as a fall resulting in hospitalization, fracture, head trauma or death. Controls (3:1) were frequency-matched to cases. Benzodiazepine exposure was the use of benzodiazepines over the previous 2 weeks reported at the follow-up visit preceding the fall.ResultsBenzodiazepine use was significantly associated with the occurrence of injurious falls, with a significant interaction with age. The adjusted odds ratio for injurious falls in subjects exposed to benzodiazepines was 2.2 (95% CI 1.4, 3.4) in subjects aged ≥80 years and 1.3 (95% CI 0.9, 1.9) in subjects aged <80 years. The population attributable risk for injurious falls in subjects exposed to benzodiazepines was 28.1% (95% CI 16.7, 43.2) for subjects aged ≥80 years. The incidence of injurious falls in subjects aged ≥80 years exposed to benzodiazepines in the PAQUID cohort was 2.8/100 person-years. Over 9% of these falls were fatal. According to these results and to recent population estimates, benzodiazepine use could be held responsible for almost 20 000 injurious falls in subjects aged ≥80 years every year in France, and for nearly 1800 deaths.ConclusionGiven the considerable morbidity and mortality associated with benzodiazepine use and the fact that existing good practice guidelines on benzodiazepines have not been effective in preventing their misuse (possibly because they have not been applied), new methods for limiting use of benzodiazepines in the elderly need to be found.

Impact of safety alerts on measures of disproportionality in spontaneous reporting databases : The notoriety bias

AbstractBackground: Disproportionality analysis of spontaneous reporting is increasingly used, but it may be influenced in unknown ways by safety alerts (notoriety bias). Objective: To explore the consequences of safety alerts on reporting disproportionality. Methods: Within the French national pharmacovigilance database, disproportionality of reporting was tested, using the reporting odds ratio (ROR) and its 95% confidence interval, before and after four safety alerts: valvulopathies with pergolide; tuberculosis with infliximab; strokes with atypical antipsychotics; and rhabdomyolysis with HMG-CoA reductase inhibitors (statins) [after cerivastatin withdrawal]. Results: No cases of valvulopathy were reported in association with pergolide before the safety alert and 63 cases were reported after the alert, (ROR 9400; 95% CI4300, 20 000), of which five had occurred before the alert. Twenty-five reports mentioned rhabdomyolysis associated with statins (not including cerivastatin) before the safety alert (ROR 5.8; 95% CI 3.8, 9.0), and 63 did so after the alert (ROR 9.4; 95% CI 7.0, 13.0). Approximately 280 cases involving cerivastatin were reported after its withdrawal. There were two reports of tuberculosis associated with infliximab before the alert (ROR 1500; 95% CI 130, 18 000) and seven after the alert (ROR 430; 95% CI 110, 1700). There was one report of a stroke in association with atypical antipsychotic treatment before the safety alert (ROR 0.10; 95% CI 0.01, 0.63) and 16 after the alert (ROR 1.10; 95% CI 0.70, 1.90). After excluding events involving treatment with anticoagulant agents, the RORs for stroke in association with atypical antipsychotic treatment were 0.14 (95% CI 0.02, 1.00) before the alert and 2.0 (95% CI 1.2, 3.4) after the alert. Conclusion: Disproportionality in spontaneous reporting databases increases after a safety alert because of increased reporting of the event of interest, including reports of such events that occurred before the alert. This may overflow to increased reporting of the event in association with other drugs.

Cardiovascular and Gastrointestinal Safety of NSAIDs: A Systematic Review of Meta-Analyses of Randomized Clinical Trials

As part of the Safety of Non‐Steroidal Anti‐Inflammatory Drugs (SOS) Project, we reviewed the incidence of cardiovascular (CV) and gastrointestinal (GI) events associated with the use of this category of drugs. We collected data from published meta‐analyses (MAs) of clinical trials of nonsteroidal anti‐inflammatory drugs (NSAIDs). The Medline, Cochrane, ISI, and SCOPUS databases were systematically searched for MAs of NSAID clinical trials that could potentially contain data on adverse incidents such as myocardial infarction (MI), cerebrovascular events (CeVs), stroke, thromboembolic events (ThEs), heart failure (HF), gastrointestinal bleeding (GIB), and perforation, ulcer, and bleeding (PUB). From 1,733 identified references, 29 MAs were selected for the review. This allowed 109 estimations of incidence rates of CV adverse events and 26 estimations of incidence rates for GI adverse events. No data were found on hemorrhagic stroke or LGIB. Coxibs were studied in more MAs than traditional NSAIDs were (21 MAs for coxibs vs. 7 for traditional NSAIDs; one meta‐analysis studied both). Many NSAIDs were not considered in any of the MAs. Our systematic review of MAs included information on the incidence of CV and GI events and identified important knowledge gaps regarding, in particular, the CV safety of traditional NSAIDs.

Stroke risk and NSAIDs: a systematic review of observational studies

To perform a quantitative systematic review of observational studies on the risk of stroke associated with the use of individual NSAIDs.

Antipsychotic Use and Myocardial Infarction in Older Patients With Treated Dementia

BACKGROUND Antipsychotic agents (APs) are commonly prescribed to older patients with dementia. Antipsychotic use is associated with an increased risk of ischemic stroke in this population. Our study aimed to investigate the association of AP use with the risk of acute myocardial infarction (MI). METHODS A retrospective cohort of community-dwelling older patients who initiated cholinesterase inhibitor treatment was identified between January 1, 2000, and December 31, 2009, using the Quebec, Canada, prescription claims database. From this source cohort, all new AP users during the study period were matched with a random sample of AP nonusers. The risk of MI was evaluated using Cox proportional hazards models, adjusting for age, sex, cardiovascular risk factors, psychotropic drug use, and propensity scores. In addition, a self-controlled case series study using conditional Poisson regression modeling was conducted. RESULTS Among the source cohort of 37,138 cholinesterase inhibitor users, 10,969 (29.5%) initiated AP treatment. Within 1 year of initiating AP treatment, 1.3% of them had an incident MI. Hazard ratios for the risk of MI after initiation of AP treatment were 2.19 (95% CI, 1.11-4.32) for the first 30 days, 1.62 (95% CI, 0.99-2.65) for the first 60 days, 1.36 (95% CI, 0.89-2.08) for the first 90 days, and 1.15 (95% CI, 0.89-1.47) for the first 365 days. The self-controlled case series study conducted among 804 incident cases of MI among new AP users yielded incidence rate ratios of 1.78 (95% CI, 1.26-2.52) for the 1- to 30-day period, 1.67 (95% CI, 1.09-2.56) for the 31- to 60-day period, and 1.37 (95% CI, 0.82-2.28) for the 61- to 90-day period. CONCLUSION Antipsychotic use is associated with a modest and time-limited increase in the risk of MI among community-dwelling older patients treated with cholinesterase inhibitors.

A Reference Standard for Evaluation of Methods for Drug Safety Signal Detection Using Electronic Healthcare Record Databases

BackgroundThe growing interest in using electronic healthcare record (EHR) databases for drug safety surveillance has spurred development of new methodologies for signal detection. Although several drugs have been withdrawn postmarketing by regulatory authorities after scientific evaluation of harms and benefits, there is no definitive list of confirmed signals (i.e. list of all known adverse reactions and which drugs can cause them). As there is no true gold standard, prospective evaluation of signal detection methods remains a challenge.ObjectiveWithin the context of methods development and evaluation in the EU-ADR Project (Exploring and Understanding Adverse Drug Reactions by integrative mining of clinical records and biomedical knowledge), we propose a surrogate reference standard of drug-adverse event associations based on existing scientific literature and expert opinion.MethodsThe reference standard was constructed for ten top-ranked events judged as important in pharmacovigilance. A stepwise approach was employed to identify which, among a list of drug-event associations, are well recognized (known positive associations) or highly unlikely (‘negative controls’) based on MEDLINE-indexed publications, drug product labels, spontaneous reports made to the WHO’s pharmacovigilance database, and expert opinion. Only drugs with adequate exposure in the EU-ADR database network (comprising ≈60 million person-years of healthcare data) to allow detection of an association were considered. Manual verification of positive associations and negative controls was independently performed by two experts proficient in clinical medicine, pharmacoepidemiology and pharmacovigilance. A third expert adjudicated equivocal cases and arbitrated any disagreement between evaluators.ResultsOverall, 94 drug-event associations comprised the reference standard, which included 44 positive associations and 50 negative controls for the ten events of interest: bullous eruptions; acute renal failure; anaphylactic shock; acute myocardial infarction; rhabdomyolysis; aplastic anaemia/pancytopenia; neutropenia/agranulocytosis; cardiac valve fibrosis; acute liver injury; and upper gastrointestinal bleeding. For cardiac valve fibrosis, there was no drug with adequate exposure in the database network that satisfied the criteria for a positive association.ConclusionA strategy for the construction of a reference standard to evaluate signal detection methods that use EHR has been proposed. The resulting reference standard is by no means definitive, however, and should be seen as dynamic. As knowledge on drug safety evolves over time and new issues in drug safety arise, this reference standard can be re-evaluated.

Rituximab therapy for childhood Evans syndrome

The safety and efficacy of rituximab have been retrospectively assessed in 17 children with Evans syndrome. Patients received 4 or 3 weekly doses of rituximab (375 mg/m2 per dose) associated with prednisone, alone (14 patients) or associated with other immunosuppressive drugs. Complete or partial remission of at least one cytopenia was achieved in 13 out of the 17 patients (76%), and lasted in 11 of them with a mean follow-up of 2.4 years (range 0.5–7 years). Steroid therapy was stopped or tapered at 50–100% of the baseline dosage in all long-term responders. Moderate side effects and infection occurred only in 4 and 1 children respectively.