Josiane Courteau

Optimal strategy to identify incidence of diagnostic of diabetes using administrative data

BackgroundAccurate estimates of incidence and prevalence of the disease is a vital step toward appropriate interventions for chronic disease like diabetes. A growing body of scientific literature is now available on producing accurate information from administrative data. Advantages of use of administrative data to determine disease incidence include feasibility, accessibility and low cost, but straightforward use of administrative data can produce biased information on incident cases of chronic disease like diabetes. The present study aimed to compare criteria for the selection of diabetes incident cases in a medical administrative database.MethodsAn exhaustive retrospective cohort of diabetes cases was constructed for 2002 using the Canadian National Diabetes Surveillance System case definition (one hospitalization or two physician claims with a diagnosis of diabetes over a 2-year period) with the Quebec health service database. To identify previous occurrence of diabetes in the database, a five-year observation period was evaluated using retrograde survival function and kappa agreement. The use of NDSS case definition to identify incident cases was compared to a single occurrence of an ICD-9 code 250 in the records using the McNemar test.ResultsRetrograde survival function showed that the probability of being a true incident case after a 5-year diabetes-free observation period was almost constant and near 0.14. Agreement between 10 years (maximum period) and 5 years and more diabetes-free observation periods were excellent (kappa > 0.9). Respectively 41,261 and 37,473 incident cases were identified using a 5-year diabetes-free observation period with NDSS definition and using a single ICD-9 code 250.ConclusionA 5-year diabetes-free observation period was a conservative time to identify incident cases in an administrative database using one ICD-9 code 250 record.

Bone mineral density measurement and osteoporosis treatment after a fragility fracture in older adults: regional variation and determinants of use in Quebec

BackgroundOsteoporosis (OP) is a skeletal disorder characterized by reduced bone strength and predisposition to increased risk of fracture, with consequent increased risk of morbidity and mortality. It is therefore an important public health problem. International and Canadian associations have issued clinical guidelines for the diagnosis and treatment of OP. In this study, we identified potential predictors of bone mineral density (BMD) testing and OP treatment, which include place of residence.MethodsOur study was a retrospective population-based cohort study using data from the Quebec Health Insurance Board. The studied population consisted of all individuals 65 years and older for whom a physician claimed a consultation for a low velocity vertebral, hip, wrist, or humerus fracture in 1999 and 2000. Individuals were considered to have undergone BMD testing if there was a claim for such a procedure within two years following a fracture. They were considered to have received an OP treatment if there was at least one claim to Quebecs health insurance plan (RAMQ) for OP treatment within one year following a fracture. We performed descriptive analyses and logistic regressions by gender. Predictors included age, site of fracture, social status, comorbidity index, prior BMD testing, prior OP treatment, long-term glucocorticoid use, and physical distance to BMD device.ResultsThe cohort, 77% of which was female, consisted of 25,852 individuals with fragility fractures. BMD testing and OP treatment rates were low and gender dependent (BMD: men 4.6%; women 13.1%; OP treatment: men 9.9%; women 29.7%). There was an obvious regional variation, particularly in BMD testing, ranging from 0 to 16%. Logistic regressions demonstrate that individuals living in long term care facilities received less BMD testing. Patients who had suffered from vertebral fractures, or who had received prior OP treatment or BMD testing, regardless of gender, subsequently received more BMD testing and OP treatments. Furthermore, increasing the distance between a patients residence and BMD facility precluded likelihood of BMD testing.ConclusionBMD testing rate was extremely low but not completely explained by reduced physical access; gender, age, social status, prior BMD testing and OP treatment were all important predictors for future BMD testing and OP treatment.

Thiols can either enhance or suppress DNA damage induction by catecholestrogens

The estrogen metabolites catecholestrogens (or hydroxyestrogens) are involved in carcinogenesis and the development of resistance to methotrexate. This induction of drug resistance correlates with the relative efficiency of catecholestrogens in the generation of reactive oxygen species (ROS) and the induction of DNA strand breaks. Although antioxidants can neutralize ROS, the generation of these reactive species by catecholestrogens can be enhanced by electron donors like NADH. Therefore, this study was undertaken to determine the ability of different thiol agents (GSH, NAC, DTT, DHLA) to either inhibit or enhance the level of DNA damage induced by the H(2)O(2) generating system 4-hydroxyestradiol/Cu(II). Our results show that GSH, DTT, and DHLA inhibited the induction of the 4-hydroxyestradiol/Cu(II)-mediated DNA damage, with GSH showing the best potential. In contrast, the GSH precursor NAC at low concentrations was able to enhance the level of oxidative damage, as observed with NADH. NAC can reduce Cu(II) to Cu(I) producing the radical NAC&z.rad;, which can generate the superoxide anion. However, the importance of this pathway appears to be relatively minor since the addition of NAC to the 4-hydroxyestradiol/Cu(II) system generates about 15 times more DNA strand breaks than NAC and Cu(II) alone. We suggest that NAC can perpetuate the redox cycle between the quinone and the semiquinone forms of the catecholestrogens, thereby enhancing the production of ROS. In conclusion, this study demonstrates the crucial importance of the choice of antioxidant as potential therapy against the negative biological effects of estrogens.

Eosinophils in COPD Exacerbations Are Associated With Increased Readmissions.

Background: A subset of patients with COPD demonstrates eosinophilic inflammation either in their sputum or blood. Previous studies regarding the association between increased blood eosinophil levels and poor readmission outcomes are conflicting. The goal of this study was to investigate outcomes following severe COPD exacerbations in patients with higher blood eosinophil levels. Methods: With an observational study design, data on hospitalizations for severe COPD exacerbation were retrospectively gathered. Patient health data previous to and up to 1 year following the index hospitalization were included. Patients were stratified into the eosinophilic group if the blood eosinophil level on admission was ≥ 200 cells/&mgr;L and/or ≥ 2% of the total WBC count. Clinical outcomes were 12‐month COPD‐related readmission, 12‐month all‐cause readmission, length of stay, and time to COPD‐related readmission. These outcomes were analyzed by using logistic, negative binomial, and Cox regression models. Results: A total of 167 patients were included; 55 had eosinophilia. Eosinophilia was associated with an increased risk of 12‐month COPD‐related readmission (OR, 3.59 [95% CI, 1.65–7.82]; P = .0013), an increased risk of 12‐month all‐cause readmission (2.32 [95% CI, 1.10–4.92]; P = .0277), and a shorter time to first COPD‐related readmission (hazard ratio, 2.74 [1.56–4.83]; P = .0005). The length of stay was not statistically different between eosinophilic and noneosinophilic patients. Sensitivity analyses using different eosinophilia definitions revealed a proportional increase in effect size with increasing eosinophil cell count definitions for predicting 12‐month readmissions. Conclusions: Blood eosinophil levels can be used as a biomarker in severe COPD exacerbations for predicting higher readmission rates.

Prevalence of claims-based recurrent low back pain in a Canadian population: A secondary analysis of an administrative database

BackgroundThere is a vast literature reporting that the point prevalence of low back pain (LBP) is high and increasing. It is also known that a large proportion of acute LBP episodes are recurrent within 12 months. However, few studies report the annual trends in the prevalence of recurrent LBP or describe these trends according to age and sex categories.MethodsWe conducted a retrospective cohort study involving 401 264 adults selected from the administrative database of physician claims for the province of Quebec, Canada. These adults, aged 18 years and over, met the criteria of having consulted a physician three times within a 365-day period between 2000 and 2007 for a LBP condition corresponding to ICD-9 codes 721, 722, 724 or 739. All data were analyzed by sex and clustered according to specific age categories.ResultsWe observed a decrease from 1.64% to 1.33% in the annual prevalence between 2000 and 2007 for men. This decrease in prevalence was mostly observed between 35 and 59 years of age. Older (≥65 years) women were 1.35 times more at risk to consult a physician for LBP in a recurrent manner than older men. The most frequently reported diagnosis was non-specific LBP between 2000 to 2007. During the same period, sequelae of previous back surgery and spinal stenosis were the categories with the largest increases.ConclusionThe annual prevalence of claims-based recurrent LBP progressively decreased between 2000 and 2007 for younger adults (<65 years) while older adults (≥65 years) showed an increase. Given the aging Canadian population, recurrent low back pain could have an increasing impact on the quality of life of the elderly as well as on the healthcare system.

Comparative effectiveness and safety of antipsychotic drugs in schizophrenia treatment: a real-world observational study

The objective was to compare, in a real‐world setting, the risk of mental and physical health events associated with different antipsychotic drugs (clozapine, olanzapine, risperidone, quetiapine and first‐generation antipsychotics) in patients with SZ.

Spatial variation in the management and outcomes of acute coronary syndrome

BackgroundRegional disparities in medical care and outcomes with patients suffering from an acute coronary syndrome (ACS) have been reported and raise the need to a better understanding of links between treatment, care and outcomes. Little is known about the relationship and its spatial variability between invasive cardiac procedure (ICP), hospital death (HD), length of stay (LoS) and early hospital readmission (EHR). The objectives were to describe and compare the regional rates of ICP, HD, EHR, and the average LoS after an ACS in 2000 in the province of Quebec. We also assessed whether there was a relationship between ICP and HD, LoS, and EHR, and if the relationships varied spatially.MethodsUsing secondary data from a provincial hospital register, a population-based retrospective cohort of 24,544 patients hospitalized in Quebec (Canada) for an ACS in 2000 was built. ACS was defined as myocardial infarction (ICD-9: 410) or unstable angina (ICD-9: 411). ICP was defined as the presence of angiography, angioplasty or aortocoronary bypass (CCA: 480–483, 489), HD as all death cause at index hospitalization, LoS as the number of days between admission and discharge from the index hospitalization, and EHR as hospital readmission for a coronary heart disease ≤30 days after discharge from hospital. The EHR was evaluated on survivors at discharge.ResultsICP rate was 43.7% varying from 29.4% to 51.6% according to regions. HD rate was 6.9% (range: 3.3–8.2%), average LoS was 11.5 days (range: 7.5–14.4; median LoS: 8 days) and EHR rate was 8.3% (range: 4.7–14.2%). ICP was positively associated with LoS and negatively with HD and EHR; the relationship between ICP and LoS varied spatially. An increased distance to a specialized cardiology center was associated with a decreased likelihood of ICP, a decrease in LoS, but an increased likelihood of EHR.ConclusionThe main results of this study are the regional variability of the outcomes even after accounting for age, gender, ICP and distance to a cardiology center; the significant relationships between ICP and HD, LoS and EHR, and the spatial variability in the relationships between ICP and LoS.

Does elapsed time between first diagnosis of schizophrenia and migration between health territories vary by place of residence? A survival analysis approach

Migration of patients with schizophrenia might influence health care access and utilization. However, the time between diagnosis and migration of these patients has not yet been explored. We studied the first migration between health territories of 6873 patients newly diagnosed with schizophrenia in Quebec in 2001, aiming to describe the pattern of migration and assess the influence of the place of residence on migration. Between 2001 and 2007, 34.5% of patients migrated between health territories; those living in metropolitan areas were more likely to migrate than others but tended to remain in metropolitan areas. Migrant patients were also more likely to stay in or migrate to the most socially or materially deprived territories.

Stroke and cardiovascular morbidity and mortality associated with rosiglitazone use in elderly diabetic patients.

The objective was to evaluate the cardiovascular risks associated with rosiglitazone in diabetic patients. We conducted matched nested case—control studies in a retrospective population-based cohort of all elderly diabetic patients living in Quebec throughout 2001 and 2002. Study end-points were: all-cause and cardiovascular death, hospital admission for AMI, CHF and stroke.Twenty controls per case, matched for age, gender and date of cohort entry, were randomly drawn from each cases risk set. Conditional logistic regressions were adjusted for co-morbidities and other drug exposures. The risk of hospital admission for AMI (HR 1.41, 95% CI 1.21—1.65) and CHF (HR 1.94, 95% CI 1.71—2.19) was increased by the use of rosiglitazone. However, exposure to rosiglitazone was not associated with an increased risk of cardiovascular mortality (HR 0.88, 95% CI 0.69—1.12) and all-causes mortality (HR 0.87, 95% CI 0.76—0.99).The risk of hospital admission for stroke was not significantly affected by rosiglitazone use. Further studies are needed to better understand the mechanisms explaining these associations.

Family history and the risk of coronary heart disease: Comparing predictive models

Family history is commonly used when evaluating coronary heart disease (CHD) risk yet it is usually treated as a simple binary variable according to the occurrence or non-occurrence of disease. This definition however fails to consider the potential components of a family history which may in fact exert different degrees of influence on the overall risk profile. The purpose of this paper is to compare different predictive models for CHD which incorporate family history as either a binary variable or different types of family risk indices in terms of their predictive ability. Models for estimating CHD risk were constructed based on usual risk factors and different family history variables. This construction was accomplished using logistic regression and RECursive Partition and AMalgamation (RECPAM) trees. Our analyses demonstrate the importance of using more sophisticated definitions of family history variables compared to a simple binary approach since this leads to a significant improvement in the predictive ability of CHD risk models.