Régie De L'assurance Maladie Du Québec Research Articles

Geographical discrepancy in oral food challenge utilization based on Canadian billing data

BackgroundOral food challenges (OFC) confer the highest sensitivity and specificity in diagnosis; however, uptake has been variable across clinical settings. Numerous barriers were identified in literature from inadequate training to resource access. OFC utilization patterns using billing data have not been previously studied.ObjectiveThe objective of this study is to explore the geographic differences in utilization of OFCs across Ontario and Québec using anonymized billing data from 2013 to 2017.MethodsAnonymized OFC billing data were obtained between 2013 and 2017 from Ontario Health Insurance Plan (OHIP) and Régie de l'Assurance Maladie du Québec (RAMQ). The number of OFCs was extracted by location, billings, and physician demographics for clinic and hospital-based challenges.ResultsOver the period studied, the number of OFCs increased by 92% and 85% in Ontario clinics and Québec hospitals, respectively. For Ontario hospitals, the number of OFCs increased by 194%. While Québec performed exclusively hospital-based OFCs, after controlling for the population, the number of OFCs per 100,000 residents annually were similar to Ontario at 50 and 49 OFCs, respectively. The number of OFCs varied across the regions studied with an annual rate reaching up to 156 OFCs per 100,000 residents in urban regions and as low as 0.1 in regions furthest from city centers.ConclusionOFC utilization has steadily increased over the last decade. There has been marked geographical discrepancies in OFC utilization which could be driven by the location of allergists and heterogeneity in their practices. More research is needed to identify barriers and propose solutions to them.

The Risk of Bleeding in Pregnant Women with Acute Venous Thromboembolism Treated with Anticoagulants

Introduction Women are at an increased risk of venous thromboembolism (VTE) during pregnancy and the postpartum period. VTE, which includes pulmonary embolism (PE) and deep vein thrombosis (DVT), complicates 1 to 2 of 1000 pregnancies and is an important cause of maternal morbidity and mortality. The risk of VTE during pregnancy is increased five to ten-fold compared to the non-pregnant woman of comparable age. During pregnancy, subcutaneous weight-adjusted low-molecular-weight-heparin (LMWH) is the standard anticoagulation therapy for acute VTE. Women receive a minimum of 3 months of LMWH with treatment generally extended throughout pregnancy and for at least 6 weeks following delivery given the additional increased VTE risk during the postpartum period. Variable estimates are reported in the literature pertaining to the risk of bleeding in pregnant patients treated with therapeutic anticoagulation. The risk of major bleeding, as defined by the study, ranges between 2.9 and 30.0% according to a recent systematic review of the literature. The ability to make inference is limited by the small number of patients included in the studies and the substantial heterogeneity of bleeding definitions used. The paucity of data doesn't allow healthcare providers to accurately estimate the risk of bleeding in this population and prevents adequate patient counselling. As such, we conducted a population-based cohort study to evaluate the risk of bleeding events among pregnant women with acute VTE treated with LMWH anticoagulants. Methods We conducted a retrospective cohort study using data from electronic healthcare databases from the province of Quebec, Canada, including the Régie de l'assurance maladie du Québec (RAMQ), the Maintenance et Exploitation des Données pour l'Étude de la Clientèle Hospitalière (Med-Echo) and the Institut de la statistique du Québec (ISQ). From an inception cohort of Quebec residents with a diagnosis of incident VTE between January 1, 1998, and December 31, 2015, we created a study cohort of pregnant women diagnosed with VTE during pregnancy who received a prescription for LMWH within 15 days of the incident event. When the gestational age of pregnant women was not available in the database, a previously described algorithm was used to extrapolate the date of conception according to the delivery outcome. Women were followed until an inpatient diagnosis of bleeding within 30 days of delivery or censoring due to discontinuation of LMWH use, cessation of medication coverage eligibility, death, or the end of the study period. Major bleeding was defined as a hospitalization for bleeding within the study period. Results Of the 325,560 patients included in the inception VTE cohort, 259 pregnant patients remained after the exclusion criteria were applied. The mean age of patients was 29 years-old, 80.9% of patients had a DVT and 19.5% had a PE. 72.6% of patients received Dalteparin, while the other patients received Tinzaparin or Enoxaparin. In total, 20 patients (7.7%) experienced bleeding requiring hospitalization during the study period, 5 of which were antepartum bleeding events (1.9%). The incidence rate of major bleeding was 310.5 per 1,000 person-years (95% CI 189.6-479.5). There was no bleeding-related or all-cause related mortality in this cohort. Conclusion This study provides a population-derived estimate of bleeding in pregnant women treated with therapeutic anticoagulation for VTE during pregnancy. This study has some limitations. First, data is not available for women who do not use medical services during pregnancy, those who give birth outside a hospital setting. However, given the free universal healthcare system in the province of Quebec, the effect of this on our result is expected to be minimal. Second, the RAMQ database provides information on individuals adherent to the RAMQ drug plan and welfare recipients, but not on individuals who are covered by private insurance. This may affect the generalizability of our study findings if socioeconomic status is an effect modifier. Our results show that Dalteparin is the most used LMWH in pregnancy. This study provides an estimate of bleeding events that are clinically significant and require hospitalization. Further studies are needed to evaluate the factors associated with increased bleeding in this patient population.

Is in-utero exposure to cannabis associated with the risk of attention deficit with or without hyperactivity disorder? A cohort study within the Quebec Pregnancy Cohort

Importance and objectivePrenatal cannabis effect on attention deficit with or without hyperactivity disorder (ADHD) remains to be determined. Our aim is to quantify the impact of in-utero exposure to cannabis...

Evidence of the Different Associations of Prognostic Factors With Censoring Across Treatment Groups and Impact on Censoring Weight Model Specification: The Example of Anticoagulation in Atrial Fibrillation.

Inverse probability of censoring weights (IPCWs) may reduce selection bias due to informative censoring in longitudinal studies. However, in studies with an active comparator, the associations between predictors and censoring may differ across treatment groups. We used the clinical example of anticoagulation treatment with warfarin or a direct oral anticoagulant (DOAC) in atrial fibrillation to illustrate this. The cohort of individuals initiating an oral anticoagulant during 2010-2016 was identified from the Régie de l'assurance maladie du Québec (RAMQ) databases. The parameter of interest was the hazard ratio (HR) of the composite of stroke, major bleeding, myocardial infarction, or death associated with continuous use of warfarin versus DOACs. Two strategies for the specification of the model for estimation of censoring weights were explored: exposure-unstratified and exposure-stratified. The HR associated with continuous treatment with warfarin versus DOACs adjusted with exposure-stratified IPCWs was 1.26 (95% confidence interval: 1.20, 1.33). Using exposure-unstratified IPCWs, the HR differed by 15% in favor of DOACs (1.41, 95% confidence interval: 1.34, 1.48). Not accounting for the different associations between the predictors and informative censoring across exposure groups may lead to misspecification of censoring weights and biased estimate on comparative effectiveness and safety.

Profiles of Frequent Geriatric Users of Emergency Departments: A Latent Class Analysis.

Frequent geriatric users of emergency departments (EDs) represent a complex and heterogeneous population. Identifying their specific subgroups would allow the development of interventions better customized to their needs and characteristics. Thus, this study aimed to develop profiles of frequent geriatric ED users using the individual characteristics of patients. This was a retrospective cohort study. Databases from the Régie de l'assurance maladie du Québec (RAMQ) were utilized. PARTICIPANTSThis study included individuals aged 65 years or older living in the community in the Province of Quebec (Canada), who consulted in an ED at least four times in the year after an ED index date (an ED visit, chosen randomly, during an index period of January 1, 2012 to December 31, 2013) and who had received a diagnosis of ambulatory care-sensitive conditions (ACSCs) in the 2 years preceding the index date. A latent class analysis was used to identify subgroups of frequent geriatric ED users according to their individual characteristics, including ACSC type, dementia, mental health disorders, cancer diagnosis, and comorbidity index. The study cohort consisted of 21,393 frequent geriatric ED users. Four groups of frequent geriatric ED users were identified: people with low comorbidity (39.0%), comprising the individuals with the lowest number of physical and mental health conditions; people with cancer (32.7%); people with pulmonaryand cardiac diseases (18.1%); and people with dementia or mental health disorders (10.2%), composed of individuals with the highest proportion of common and severe mental health disease, as well as dementia. This group accounts for the highest use of overall healthcare services. These profiles will be useful in developing customized interventions addressing the needs of each subgroup of frequent geriatric ED users. More research is needed to bridge the remaining gaps, especially regarding the healthiest frequent geriatric users of EDs.

Is there an agreement between self-reported medical diagnosis in the CARTaGENE cohort and the Québec administrative health databases?

BackgroundPopulation health studies often use existing databases that are not necessarily constituted for research purposes. The question arises as to whether different data sources such as in administrative health data (AHD) and self-report questionnaires are equivalent and lead to similar information. ObjectivesThe main objective of this study was to assess the level of agreement between self-reported medical conditions and medical diagnosis captured in AHD. A secondary objective was to identify predictors of agreement among medical conditions between the two data sources. Therefore, the purposes of the study were to explore the extent to which these two methods of commonly used public health data collection provide concordant records and identify the main predictors of statistical variations. MethodsData were extracted from CARTaGENE, a population-based cohort in Québec, Canada, which was linked to the provincial health insurance records of the same individuals, namely the MED-ÉCHO database from the Régie de l’assurance maladie du Québec (RAMQ) and the fee-for-service billing records provided by the physician, for the time period 1998-2012. Agreement statistics (kappa coefficient) along with sensitivity, specificity and predictive positive value were calculated for 19 chronic conditions and 12 types of cancers. Logistic regressions were used to identify predictors of concordance between self-report and AHD from significant covariates (sex, age groups, education, region, income, heavy utilization of health care system and Charlson comorbidity index).ResultsAgreement between self-reported data and AHD across diseases ranged from kappa of 0.09 for chronic renal failure to 0.86 for type 2 diabetes. Sensitivity of self-reported data was higher than 50% for 14 out of the 31 medical conditions studied, especially for myocardial infarction (88.62%), breast cancer (86.28%), and diabetes (85.06%). Specificity was generally high with a minimum value of 89.70%. Lower concordance between data sources was observed for higher frequency of health care utilization and higher comorbidity scores.ConclusionOverall, there was moderate agreement between the two data sources but important variations were found depending on the type of disease. This suggests that CARTaGENE’s participants were generally able to correctly identify the kind of diseases they suffer from, with some exceptions. These results may help researchers choose adequate data sources according to specific study objectives. These results also suggest that Québec’s AHD seem to underestimate the prevalence of some chronic conditions, which might result in inaccurate estimates of morbidity with consequences for public health surveillance

A real-world observational study of somatostatin analogue use and costs in Canada.

608 Background: Somatostatin analogue (SSA) use is indicated in acromegaly and neuroendocrine tumours for symptomatic relief and tumour control. Two long-acting SSAs (lanreotide and octreotide) are currently available, but comparative real-world data on their use are limited. This study evaluated SSA use and costs in Canada. Methods: Claims data from the IQVIA Private Drug Plan (PDP), Ontario Drug Benefit (ODB) program and Régie de l’assurance-maladie du Québec (RAMQ) were compiled. Injection burden, rescue medication use and costs were compared (using unpaired t-test or Wilcoxon test) over a 12-month period from first SSA prescription. Patients (pts) were eligible if the first prescription was dispensed Sept. 2015–Jun. 2018. Results: 908 pts were included: lanreotide 120 mg, N=375; octreotide long-acting release (LAR) 30 mg, N=533. Lanreotide treatment was associated with a lower weighted average injection burden for 12 months when compared to octreotide (12.54 vs 13.44 injections/pt, respectively; p<0.0001). Pts receiving lanreotide also had lower mean use of rescue medications than those treated with octreotide (0.01 vs 0.05 claims/pt/year), although this difference was greatest during the first month of treatment (mean difference: 0.19; p<0.0001), after which differences in rescue medication use were only significant (p<0.05) at Months 5 and 6. Mean total annual costs (rescue medication + LAR) were lower for lanreotide than octreotide ($27,829.35/pt [N=373] vs $31,255.49/pt [N=530], respectively, p<0.0001). Conclusions: In the absence of clinical trials directly comparing the SSAs, factors driving treatment selection are unclear. Findings from our real-world observational study suggest treatment with lanreotide to be less burdensome and costly than octreotide and may inform treatment discussions with pts.

Anticoagulants in Older Patients with Nonvalvular Atrial Fibrillation after Intracranial Hemorrhage

Background and PurposePatients with nonvalvular atrial fibrillation (NVAF) who survive an intracranial hemorrhage (ICH) have an increased risk of ischemic stroke and systemic embolism (IS/ SE). We investigated whether starting oral anticoagulants (OACs) among older NVAF patients after an ICH was associated with a lower risk of IS/SE and mortality but offset by an increase in major bleeding. MethodsWe assembled a patient cohort from the Quebec Régie de l’Assurance Maladie du Québec (RAMQ) and Med-Echo administrative databases. We identified older adults with NVAF from 1995 to 2015. All patients with incident ICH and discharged in community were included. Patients were categorized according to OAC exposure. Outcomes included IS/SE, all-cause mortality, recurrent ICH and major bleeding after a quarantine period of 6 weeks. Crude event rates were calculated at 1-year of follow-up, and Cox proportional hazard models with a time-dependent binary exposure were used to assess adjusted hazard ratios (AHRs). ResultsThe cohort of 683 NVAF patients with ICH aged 83 years on average. The rates (per 100 person-years) for IS/SE, death, ICH and major bleeding were 3.3, 40.6, 11.4, and 2.7 for the no OAC group; and 2.6, 16.3, 5.2, and 5.2 for OAC group, respectively. The AHR for IS/SE and death was 0.10 (95% confidence interval [CI], 0.05 to 0.21), 0.43 (95% CI, 0.19 to 0.97) for recurrent ICH and 1.73 (95% CI, 0.71 to 4.20) for major extracranial bleeding comparing OAC exposure to non-exposed. ConclusionsInitiating OAC after ICH in older individuals with NVAF is associated with a reduction of IS/SE and mortality and a trend in recurrent ICH supporting its use after ICH.

Identifying Rheumatoid Arthritis Cases within the Quebec Health Administrative Database.

Our objective was to calculate rheumatoid arthritis (RA) point prevalence estimates in the CARTaGENE cohort, as well as to estimate the sensitivity and specificity of our ascertainment approach, using physician billing data. We investigated the effects of using varying observation windows in the Régie de l'assurance maladie du Québec (RAMQ) health services administrative databases, alone or in combination with self-reported diagnoses and drugs. We studied subjects enrolled in the CARTaGENE cohort, which recruited 19,995 participants from 4 metropolitan regions in Québec from August 2009 to October 2010. A series of Bayesian latent class models were developed to assess the effects of 3 factors: the number of years of billing data, the addition of self-reported information on RA diagnoses and drugs, and the adjustment for misclassification error. The 3-year 2010 point prevalence estimate among cohort members aged 40-69 years, using physician billing plus self-report, adjusting for misclassification error in each source, was 0.9% [95% credible interval (CrI) 0.7-1.2] with RAMQ sensitivity of 84.0% (95% CrI 74.0-93.7) and a specificity of 99.8% (95% CrI 99.6-100.0). Our results show variations in the prevalence point estimates related to all 3 factors investigated. Our study illustrates that multiple data sources identify more RA cases and thus a higher prevalence estimate. RA point prevalence estimates using billing data are lower if fewer years of data are used.

PP68 Indicators From The Real World Data To Improve Opioid Use

IntroductionOpioids are being used increasingly to treat chronic noncancer pain despite the uncertainty regarding its long-term benefits. This study served to determine if problems are associated with opioid use in Québec for new users from 2006 to 2013 without history of cancer.MethodsA retrospective longitudinal cohort study was conducted using administrative databases stored at the Régie de l'assurance maladie du Québec (RAMQ) to describe the annual proportion of new users to whom at least one of the five indicators of potentially inappropriate opioid use applied was estimated. These indicators are (i) overlapping opioid prescriptions, (ii) overlapping opioid and benzodiazepine prescriptions, (iii) the use of long-acting opioids at the start of treatment, (iv) a high mean daily dose, and (v) a rapid increase in the opioid dose.ResultsThe annual proportion of new users to whom at least one of the five indicators of potentially inappropriate opioid use applied decreased from 15.4 percent in 2006 to 12.3 percent in 2013. It was mainly the following three indicators that contributed the most to these proportions in 2013: (i) overlapping opioid prescriptions (5.8 percent), (ii) overlapping opioid and benzodiazepine prescriptions (8.2 percent), and (iii) the use of long-acting opioids at the start of treatment (1.8 percent).ConclusionsThe vast majority of new users with no history of diagnosed cancer used opioids adequately according to the five indicators of potentially inappropriate opioid use applied. Improvement could still be made to decrease mainly overlapping opioid prescriptions and overlapping opioid and benzodiazepine prescriptions.

Association Between Low-Molecular-Weight Heparin and Risk of Bleeding Among Hemodialysis Patients: A Retrospective Cohort Study.

Background:Low-molecular-weight heparins (LMWH) replaced unfractionated heparin (UFH) in multiple indications. Although LMWH efficacy in hemodialysis was demonstrated through multiple studies, their safety remains controversial. The potential bioaccumulation in patients undergoing chronic hemodialysis raised the question of bleeding risk among this population.Objective:The aim of this study was to evaluate bleeding risk among patients with chronic hemodialysis receiving LMWH or UFH for the extracorporeal circuit anticoagulation.Design:We conducted a retrospective cohort study on data extracted from the Régie de l’assurance maladie du Québec (RAMQ) and Med-Echo databases from January 2007 to March 2013.Setting:Twenty-one hemodialysis centers in the province of Québec, Canada.Patients:Chronic hemodialysis patients.Measurements:Bleeding risk evaluated by proportional Cox model for time-dependent exposure using demographics, comorbidities, and drug use as covariates.Methods:Minor, major, and total bleeding events identified using International Classification of Diseases, Ninth Revision (ICD-9)/International Classification of Diseases, Tenth Revision (ICD-10) codes in the RAMQ and Med-Echo databases. Exposure status to LMWH or UFH was collected through surveys at the facility level.Results:We identified 5322 prevalent and incident patients with chronic hemodialysis. The incidence rate for minor, major, and total bleeding was 9.45 events/1000 patient-year (95% confidence interval [CI]: 7.61-11.03), 24.18 events/1000 patient-year (95% CI: 21.52-27.08), and 32.88 events/1000 patient-year (95% CI: 29.75-36.26), respectively. We found similar risks of minor adjusted hazard ratio (HR: 1.04; 95% CI: 0.68-1.61), major (HR: 0.83; 95% CI: 0.63-1.10), and total bleeding (HR: 0.90; 95% CI: 0.72-1.14) when comparing LMWH with UFH.Limitations:Potential misclassification of patients’ exposure status and possible underestimation of minor bleeding risk.Conclusion:LMWH was not associated with a higher minor, major, or total bleeding risk. LMWH did not increase the risk of bleeding compared with UFH for the extracorporeal circuit anticoagulation in hemodialysis. The convenience of use and predictable effect made LMWH a suitable alternative to UFH in hemodialysis.

Consultations médicales et types de services de santé utilisés dans les deux années précédant le suicide auprès des Québécois diagnostiqués avec et sans troubles mentaux et troubles avec utilisation de substances

Objectives Population based studies on linked health administrative databases (HADBs) characterizing those who die by suicide and their use of health services are rare. The objectives of this study were to describe the use of health services among people who died by suicide in Quebec, with and without previously receiving a mental disorder (MD) and dependencies (D) (MD/D) diagnosis, and (2) living Quebecers diagnosed with MD/D. Methods This study is based on an analysis of data from the Integrated Chronic Disease Surveillance System of Quebec (SISMACQ), which combines databases on outpatient medical and emergency services and hospitalizations. The population of the study consists of Quebecers aged 15 years and over and insured between April 1, 1996 and March 31, 2013 under the Régie de l'assurance maladie du Québec (RAMQ). For the purposes of this study, the 7 years preceding suicide were examined in the HADBDS for the three following cohort groups: (i) cases of suicide with a diagnosed MD/D in the 7 years preceding the date of death; (ii) cases of suicide without a MD/D diagnosis in the 7 years preceding the date of death; and (iii) a control group of living persons at the time of death of the suicide case (5 controls, 1 case) with a MD/D diagnosis within 7 years matched by region, sex and age group of the case. Results The results show that cases of suicide without a MD/D (about 25% of suicide cases) were less likely to have consulted than those with a MD/D. Suicide cases with and without a MD/D were less likely to be heavy users of ambulatory health services (≥ 4 visits) than matched living controls. They were also more likely to consult for a physical disorder alone and less likely to consult for mental health reasons. Compared to cases of suicide with a MD/D, suicide cases without MD/D were less likely to be hospitalized and more likely to have visited only an emergency room. Suicide cases diagnosed with a MD/D were more likely to be hospitalized and use emergency services alone than the other two groups. Matched living controls with a MD/D were more likely to use outpatient services alone. Conclusions These results should be compared with those emerging from systematic suicide case audits. These show a prevalence of mental disorders of 90%, especially depression, personality disorders and substance use disorders. They also show deficits in the recognition and treatment of mental disorders, which would correspond to the 25% of cases of suicide in the HADBs not diagnosed in the last 7 years. Future studies should include multivariate analyses to better elucidate health service use trajectories and patient vulnerability profiles.

The early impact of human papillomavirus vaccination on anogenital warts in Québec, Canada.

In Québec province in Canada, a public school-based and catch-up HPV vaccination programs with the quadrivalent vaccine have been introduced in September 2008 for girls aged 9-17 years. We assessed the early impact of the HPV vaccination program on the incidence of anogenital warts (AGW) in the Quebec general population. We used the provincial health administrative data of the Régie de l'assurance maladie du Québec (RAMQ). AGW were identified either through a prescription of podofilox, or a medical procedure code specific to AGW, or a diagnostic code for viral warts followed by a prescription of imiquimod or fluorouracil. Sex- and age-specific incidence rates were calculated for pre-vaccination (2004-2007) and vaccination (2009-2012) periods. We found a significant decline of 45% and 19% in the incidence of AGWs among females aged 15-19 and 20-24 years, respectively. A decline of 21% was also seen among males aged 15-19 years. The median age at an episode of AGW increased from 27 years in 2004 to 31 years in 2012 among females and remained stable in males. Our findings indicate that the HPV public vaccination program is associated with an important reduction in the incidence of AGW among young females and males. The benefit is more pronounced among females 15-19 years of age, who were eligible for the public vaccination program. The observed decline among young males could be due to herd immunity and/or privately paid vaccination.

Determinants of follow-up care associated with incident antidepressant use in older adults

ObjectivesTo determine the proportion of older adults receiving guideline concordant antidepressant therapy and to determine patient, prescriber and organizational factors associated with adequate antidepressant therapy.MethodsThe study included secondary analyses of data collected in the Étude sur la Santé des Aînés (ESA) Services study on older adults recruited while consulting in primary care clinics in one of the largest health regions of the province of Québec. Antidepressant users (n = 349) were identified from information collected from the Régie de l’Assurance Maladie du Québec (RAMQ) pharmaceutical database which holds information on all drugs dispensed to all residents covered under the public drug plan. Adequacy of antidepressant treatment was measured using three criteria: adequacy of daily dose; length of prescription (≥455 days); and ≥3 visits to the antidepressant-prescribing physician in the first 3 months after initiation of therapy. Multivariate logistic regression analyses were used to study antidepressant treatment adequacy as a function of individual, provider and healthcare system factors.ResultsAmong the antidepressant users, 44% received an adequate antidepressant treatment filling all three criteria. None of the factors studied were associated with the probability of receiving adequate treatment filling all three criteria. Psychological distress was associated with having an adequate number of visits in the 3 months following initiation. Males and those living in a metropolitan and urban area were less likely to receive an adequate dose.ConclusionsFuture research should consider factors associated with perceived effectiveness and patient treatment preferences that may explain receipt of adequate antidepressant treatment in older adults.

Revisiting sex differences in outcomes in non-valvular atrial fibrillation: a population-based cohort study.

In patients with non-valvular atrial fibrillation (NVAF), it is uncertain whether the higher risk of ischaemic stroke in women reported in some studies is due to residual confounding. We assessed this association using standard time-fixed and more accurate time-dependent adjustment for confounders. Using the computerized databases of the Régie de l'assurance maladie du Québec (RAMQ), we identified a cohort of patients with NVAF during 2000-2009 and RAMQ medication coverage. Cox proportional hazards models were used to estimate the hazard ratio (HR) of ischaemic stroke, death, and bleeding, associated with sex, adjusting for time-fixed covariates at cohort entry. This was compared with adjustment for time-dependent covariates using an age and time-matched nested case-control analysis. The cohort included 147 622 patients. During a mean follow-up of 2.9 years 11326 patients had a stroke (incidence rate 2.6 per 100 per year). Using time-fixed adjustment for confounders, women had a moderately higher risk of ischaemic stroke than men (HR 1.16 (Confidence interval (CI) 95% 1.11-1.21). Matching on age and using time-dependent adjustment for confounders, women were not at higher risk of stroke than men (Rate Ratio 1.01; 95% CI 0.97-1.05). Mortality and bleeding rates were lower in women compared with men in both analyses. In NVAF, women were not at higher risk of thromboembolic events than men in our study. The small increased risk reported in previous studies may be related to residual confounding, in particular from insufficient control for age.

Benzodiazepine use associated with co-morbid post-traumatic stress syndrome and depression in older adults seeking services in general medical settings.

Benzodiazepines (BZD) should be limited in older adults. This study aimed to determine the association between BZD use and the presence of a probable post-traumatic stress syndrome (PTSS) and whether this association is dependent on gender and co-morbid physical and mental conditions. Data were retained from the Étude sur la Santé des Aînés (ESA) - Services study (2011-2013) and included 1,453 older adults (≥65 years) who completed a face to face at-home interview, who were covered under Quebec's public drug insurance plan, and had given permission to access their Régie de l'Assurance Maladie du Québec (RAMQ) medical and pharmaceutical services data. The presence of a PTSS was measured using the Impact of Event Scale-Revised (IES-R). The use of BZD and antidepressants in the year prior to interview was ascertained from data reported in the RAMQ drug registry. The presence of depression and an anxiety disorder was assessed with the ESA-Questionnaire which was based on DSM-5 criteria. The interaction between PTSS and gender, depression, anxiety, and multi-morbidity was also assessed. The prevalence of PTSS and BZD use reached 4.5% and 31.2%. Participants with PTSS were 1.9 (95% CI = 1.1-3.2) times more likely to use BZD. The presence of depression had a negative impact on the association between BZD use and PTSS (p = 0.04). The use of BZD in older adults with PTSS is still prevalent today. Differences in benzodiazepine prescribing practices for more complex co-morbid psychiatric cases needs to be further studied.

A Bayesian Approach to Latent Class Modeling for Estimating the Prevalence of Schizophrenia Using Administrative Databases.

Estimating the incidence and the prevalence of psychotic disorders in the province of Quebec has been the object of some interest in recent years as a contribution to the epidemiological study of the causes of psychotic disorders being carried out primarily in UK and Scandinavia. A number of studies have used administrative data from the Régie de l’assurance maladie du Québec (RAMQ) that includes nearly all Quebec citizens to obtain geographical and temporal prevalence estimates for the illness. However, there has been no investigation of the validity of RAMQ diagnoses for psychotic disorders, and without a measure of the sensitivity and the specificity of these diagnoses, it is impossible to be confident in the accuracy of the estimates obtained. This paper proposes the use of latent class analysis to ascertain the validity of a diagnosis of schizophrenia using RAMQ data.

Diagnostic accuracy of algorithms to identify hepatitis C status, AIDS status, alcohol consumption and illicit drug use among patients living with HIV in an administrative healthcare database

This study aims to develop and evaluate diagnostic algorithms for AIDS, hepatitis C status, alcohol abuse and illicit drug use in the administrative healthcare database of the Province of Quebec, Canada (Régie de l'assurance-maladie du Québec (RAMQ)). We selected HIV-positive patients contributing to both the RAMQ database and a local clinical database, which was used as gold standard. We developed algorithms to identify the diagnoses of interest in RAMQ using data from hospital discharge summaries and medical and pharmaceutical claims databases. We estimated and compared sensitivity, specificity, positive predictive and negative predictive values and area under receiver operating curve for each algorithm. Four hundred twenty patients contributed to both databases. Prevalence of conditions of interest in the clinical database was as follows: AIDS 233 (55%), hepatitis C infection 105 (25%), alcohol abuse 106 (25%), illicit drug use 144 (34%) and intravenous drug use 107 (25%). Sensitivity to detect AIDS, hepatitis C, alcohol abuse, illicit drug use and intravenous drug use was 46% [95%CI: 39-53], 26% [18-35], 50% [37-57], 64% [55-72] and 70% [61-79], respectively. Specificity to detect these conditions was 91% [86-95], 97% [94-98], 92% [88-95], 95% [92-97] and 90% [87-93], respectively. Positive predictive values were 87% [80-92], 71% [54-85], 68% [56-78], 87% [79-93] and 72% [62-80], respectively. Area under receiver operating curve varied from 0.62 [0.57-0.65] for hepatitis C to 0.80 [0.76-0.85] for intravenous drug use. Sensitivity was low to detect AIDS, alcohol abuse, illicit drug use and especially hepatitis C in RAMQ. Researchers must be aware of the potential for residual confounding and must consider additional methods to control for confounding.

Is the Quebec provincial administrative database a valid source for research on chronic non-cancer pain?

The objective of this study was to evaluate the validity of diagnostic codes recorded in the Régie de l'assurance maladie du Québec (RAMQ) administrative database for identifying patients suffering from various types of chronic non-cancer pain. The validity of published International Classification of Diseases, Ninth Revision, coding algorithms for identifying patients with particular chronic pain syndromes in the RAMQ database was tested using pain specialist-established diagnostic data of 561 patients enrolled in the Quebec Pain Registry, which was used as the reference standard. Modified versions of these algorithms (i.e., adaptation of the number of healthcare encounters) were also tested. For each algorithm, sensitivity, specificity, positive/negative predictive values, and their respective 95% confidence intervals (95%CI) were calculated. In the RAMQ database, some previously published algorithms and modified versions of these algorithms were found to be valid for identifying patients suffering from chronic lumbar pain (sensitivity: 0.65, 95%CI: 0.59-0.71; specificity: 0.83, 95%CI: 0.79-0.87), chronic back pain (sensitivity: 0.70, 95%CI: 0.64-0.76; specificity: 0.73, 95%CI: 0.68-0.78), and chronic neck/back pain (sensitivity: 0.71, 95%CI: 0.65-0.76; specificity: 0.78, 95%CI: 0.72-0.82). Algorithms to identify patients with other types of chronic pain showed low sensitivity: complex regional pain syndrome (≤0.07), fibromyalgia (≤0.42), and neuropathic pain (≤0.39). Our study provides evidence supporting the value of the RAMQ administrative database for conducting research on certain types of chronic pain disorders including back and neck pain. Users should, however, be cautious about the limitations of this database for studying other types of chronic pain syndromes such as complex regional pain syndrome, fibromyalgia, and neuropathic pain.

Current era clinical outcomes of castration-resistant prostate cancer in real-life population study in Quebec, Canada.

226 Background: Prostate cancer (PCa) death is mainly due to castration-resistant PCa (CRPC) which results from disease progression despite androgen ablation therapy (ADT). Little is known about clinical outcomes and trends of real-life CRPC management in the present era, which has become very complex. Our study aimed to analyze healthcare services use, clinical outcomes and survival trends in real-life management of CRPC in Quebec, Canada. Methods: The study cohort consisted of 7,123 patients which shown evidence of CRPC from January/2001 to July/2013, selected from the public healthcare insurance programs the Régie de l’Assurance Maladie du Québec (RAMQ) databases. Survival was evaluated by Kaplan-Maier and the difference in survival between pre-/post-docetaxel (Doc) (2002-2005 vs 2008-2011) era by log-rank test. The association between Doc exposure and survival was evaluated by Cox proportional hazards model adjusted for several co-variables. Results: Chemotherapy was offered to 17% of patients, while 45% were kept on maximal androgen blockade (MAB) alone, or offered Abiraterone (3%). Androgen targeted therapies (MAB or Abiraterone) were the treatment of choice for the elderly population (mean age 78.8 and 78 ±7, respectively) while chemotherapy was offered to younger patients (mean age 72 ±7.3). Survival rates at 1 and 2 years after the initiation of chemotherapy were 52% and 26% in post-Doc era vs 46% and 17% in the pre-Doc period. In patients receiving first line chemotherapy only, hospitalization due to PCa was a poor prognostic predictor (HR: 2.0; 95%CI: 1.5-2.6), as expected. In addition among patients without previous hospitalization the risk of death was higher in the pre- vs post-Doc era (HR: 1.7 CI: 1.003-2.851). Conclusions: Patient age seems to be a strong determinant in CRPC therapy selection. In patients without serious complications leading to hospitalization, survival was greatly improved in the post-Doc era. Our data also supports that patients older than those in the TAX327 trial (72 vs 68) may equally benefit from chemotherapy. This is encouraging as we hope to observe comparable results for new approved therapies for CRPC.