Patricia Caetano

Construction and Validation of a Population-Based Bone Densitometry Database

Utilization of dual-energy X-ray absorptiometry (DXA) for the initial diagnostic assessment of osteoporosis and in monitoring treatment has risen dramatically in recent years. Population-based studies of the impact of DXA and osteoporosis remain challenging because of incomplete and fragmented test data that exist in most regions. Our aim was to create and assess completeness of a database of all clinical DXA services and test results for the province of Manitoba, Canada and to present descriptive data resulting from testing. A regionally based bone density program for the province of Manitoba, Canada was established in 1997. Subsequent DXA services were prospectively captured in a program database. This database was retrospectively populated with earlier DXA results dating back to 1990 (the year that the first DXA scanner was installed) by integrating multiple data sources. A random chart audit was performed to assess completeness and accuracy of this dataset. For comparison, testing rates determined from the DXA database were compared with physician administrative claims data. There was a high level of completeness of this database (>99%) and accurate personal identifier information sufficient for linkage with other health care administrative data (>99%). This contrasted with physician billing data that were found to be markedly incomplete. Descriptive data provide a profile of individuals receiving DXA and their test results. In conclusion, the Manitoba bone density database has great potential as a resource for clinical and health policy research because it is population based with a high level of completeness and accuracy.

Mental comorbidity and multiple sclerosis: validating administrative data to support population-based surveillance

BackgroundWhile mental comorbidity is considered common in multiple sclerosis (MS), its impact is poorly defined; methods are needed to support studies of mental comorbidity. We validated and applied administrative case definitions for any mental comorbidities in MS.MethodsUsing administrative health data we identified persons with MS and a matched general population cohort. Administrative case definitions for any mental comorbidity, any mood disorder, depression, anxiety, bipolar disorder and schizophrenia were developed and validated against medical records using a a kappa statistic (k). Using these definitions we estimated the prevalence of these comorbidities in the study populations.ResultsCompared to medical records, administrative definitions showed moderate agreement for any mental comorbidity, mood disorders and depression (all k ≥ 0.49), fair agreement for anxiety (k = 0.23) and bipolar disorder (k = 0.30), and near perfect agreement for schizophrenia (k = 1.0). The age-standardized prevalence of all mental comorbidities was higher in the MS than in the general populations: depression (31.7% vs. 20.5%), anxiety (35.6% vs. 29.6%), and bipolar disorder (5.83% vs. 3.45%), except for schizophrenia (0.93% vs. 0.93%).ConclusionsAdministrative data are a valid means of surveillance of mental comorbidity in MS. The prevalence of mental comorbidities, except schizophrenia, is increased in MS compared to the general population.

Rising prevalence of vascular comorbidities in multiple sclerosis: validation of administrative definitions for diabetes, hypertension, and hyperlipidemia.

Background: Despite the importance of comorbidity in multiple sclerosis (MS), methods for comorbidity assessment in MS are poorly developed. Objective: We validated and applied administrative case definitions for diabetes, hypertension, and hyperlipidemia in MS. Methods: Using provincial administrative data we identified persons with MS and a matched general population cohort. Case definitions for diabetes, hypertension, and hyperlipidemia were derived using hospital, physician, and prescription claims, and validated in 430 persons with MS. We examined temporal trends in the age-adjusted prevalence of these conditions from 1984–2006. Results: Agreement between various case definitions and medical records ranged from kappa (κ) =0.51–0.69 for diabetes, κ =0.21–0.71 for hyperlipidemia, and κ =0.52–0.75 for hypertension. The 2005 age-adjusted prevalence of diabetes was similar in the MS (7.62%) and general populations (8.31%; prevalence ratio [PR] 0.91; 0.81–1.03). The age-adjusted prevalence did not differ for hypertension (MS: 20.8% versus general: 22.5% [PR 0.91; 0.78–1.06]), or hyperlipidemia (MS: 13.8% versus general: 15.2% [PR 0.90; 0.67–1.22]). The prevalence of all conditions rose in both populations over the study period. Conclusion: Administrative data are a valid means of tracking diabetes, hypertension, and hyperlipidemia in MS. The prevalence of these comorbidities is similar in the MS and general populations.

Osteoporosis-related fracture case definitions for population-based administrative data

BackgroundPopulation-based administrative data have been used to study osteoporosis-related fracture risk factors and outcomes, but there has been limited research about the validity of these data for ascertaining fracture cases. The objectives of this study were to: (a) compare fracture incidence estimates from administrative data with estimates from population-based clinically-validated data, and (b) test for differences in incidence estimates from multiple administrative data case definitions.MethodsThirty-five case definitions for incident fractures of the hip, wrist, humerus, and clinical vertebrae were constructed using diagnosis codes in hospital data and diagnosis and service codes in physician billing data from Manitoba, Canada. Clinically-validated fractures were identified from the Canadian Multicentre Osteoporosis Study (CaMos). Generalized linear models were used to test for differences in incidence estimates.ResultsFor hip fracture, sex-specific differences were observed in the magnitude of under- and over-ascertainment of administrative data case definitions when compared with CaMos data. The length of the fracture-free period to ascertain incident cases had a variable effect on over-ascertainment across fracture sites, as did the use of imaging, fixation, or repair service codes. Case definitions based on hospital data resulted in under-ascertainment of incident clinical vertebral fractures. There were no significant differences in trend estimates for wrist, humerus, and clinical vertebral case definitions.ConclusionsThe validity of administrative data for estimating fracture incidence depends on the site and features of the case definition.

A population-based study of osteoporosis testing and treatment following introduction of a new bone densitometry service

Bone density measurement plays a key role in the initial diagnostic assessment of osteoporosis and in targeting pharmacologic therapies. The impact of access to dual-energy X-ray absorptiometry (DXA) on physician prescribing habits is unclear, however. We were able to directly evaluate the change in physician osteoporosis testing and prescribing following introduction of a DXA testing service in a geographic region that had previously had very limited access. This evaluation was conducted in the province of Manitoba, Canada, which has a provincially based bone density testing program and maintains a population-based bone density database that can be linked with administrative health data sources including drug prescriptions. The province of Manitoba was geographically partitioned into the urban and rural health regions serviced by the new program (urbannew and ruralnew) and the remaining urban and rural health regions which had relatively unchanged DXA access during this period (urbancontrol and ruralcontrol). Regression models of DXA testing rates and osteoporosis prescription rates were created for all older women in these regions. There was a statistically significant increase in bone density testing and BMD-guided osteoporosis treatment in the urbannew and ruralnew regions following introduction of the DXA testing service, relative to the control regions. Although the overall rate of empiric postfracture and preventive osteoporosis treatment did not show a specific region effect, when analysis was limited to nonhormonal agents there was a significant reduction in preventive and empiric postfracture treatment in some subgroups of women. These results suggest that the local availability of the bone density testing service led to an increase in objective test-guided therapy with some reduction in the use of empiric and preventive strategies and had a neutral effect on overall use of these agents.

The utility of administrative data for surveillance of comorbidity in multiple sclerosis: a validation study.

Background: Although comorbidity is important in multiple sclerosis (MS), few validated methods for its assessment exist. We validated and applied administrative case definitions for several comorbidities in MS. Methods: Using provincial administrative data we identified persons with MS and a matched general population cohort. Case definitions for chronic lung disease (CLD), epilepsy, inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and migraine were developed using administrative data, and validated against medical records. We applied these definitions to estimate the age-standardized prevalence of these comorbidities in the MS and matched cohorts. Results: Versus medical records, administrative case definitions showed moderate agreement for CLD (ĸ = 0.41), migraine (ĸ = 0.51), and epilepsy (ĸ = 0.44), fair agreement for IBS (ĸ = 0.36) and could not be calculated for IBD (small sample size). The 2005 prevalence of CLD was similar in the MS (15.6%) and general populations (14.4%). The prevalence of the remaining comorbidities was higher in the MS than the general populations: epilepsy (4.12 vs. 1.12%), IBD (0.78 vs. 0.65%), IBS (12.2 vs. 6.80%) and migraine (23.0 vs. 16.5%). Conclusions: Administrative data are valid for tracking CLD, epilepsy, and migraine in MS. The prevalence of epilepsy, IBD, IBS and migraine is increased in MS versus the general population.

Closing the gap in postfracture care at the population level: a randomized controlled trial

Background: Postfracture care is suboptimal, and strategies to address this major gap in care are necessary. We investigated whether notifications sent by mail to physicians and patients would lead to improved postfracture care. Methods: We conducted a randomized controlled trial (ClinicalTrials.gov identifier NCT00594789) in the province of Manitoba, Canada, from June 2008 to May 2010. Using medical claims data, we identified 4264 men and women age 50 years or older who recently reported major fractures, and who had not undergone recent bone mineral density testing or treatment for osteoporosis. Participants were randomized to three groups: group 1 received usual care (n = 1480), patients in group 2 had mailed notification of the fracture sent to their primary care physicians (n = 1363), and group 3 had notifications sent to both physicians and patients (n = 1421). Bone mineral density testing and the start of pharmacologic treatment for osteoporosis within the following 12 months were documented. Results: Among participants in group 1 (usual care), 15.8% of women and 7.6% of men underwent testing for bone mineral density or started pharmacologic treatment for osteoporosis. Outcome measures improved among participants in group 2 (30.3% of women and 19.0% of men, both p < 0.001) and group 3 (34.0% of women and 19.8% of men, both p < 0.001). No additional benefit was seen with patient notification in addition to physician notification. Combining groups 2 and 3, the absolute increase for the combined end point of bone mineral density testing or pharmacologic treatment was 14.9% (16.4% among women, 11.8% among men). The number needed to notify to change patient care was 7 (6 for women, 6 for men). The adjusted odds ratio (OR) to change patient care in group 2 was 2.45 (95% confidence interval [CI] 2.01–2.98); for group 3 the OR was 2.82 (95% CI 2.33–3.43). Interpretation: This notification system provides a relatively simple way to enhance post-fracture care.

Effectiveness of the pandemic H1N1 influenza vaccines against laboratory-confirmed H1N1 infections: population-based case-control study.

BACKGROUND Excellent immune responses following 1 or 2 doses of the monovalent inactivated pandemic H1N1 vaccines have been documented, but the effectiveness of these vaccines against laboratory-confirmed H1N1 infections in the general population is not clear. We evaluated the effectiveness of the pandemic H1N1 and seasonal trivalent influenza vaccines (TIV) used during the 2009 mass vaccination campaign in Manitoba (Canada) in preventing laboratory-confirmed H1N1 infections. METHODS A population-based case-control study using data from Cadham Provincial Laboratory (CPL) and the Manitoba Immunization Monitoring System (MIMS). All Manitoba residents ≥6 months of age who had a respiratory specimen tested at CPL for H1N1 were included in the study. Cases were individuals who tested positive for pandemic H1N1 influenza A by reverse transcriptase-PCR (N=1435). Controls were individuals who tested negative for both influenza A and B (N=2309). Information on receipt of TIV or H1N1 vaccine was obtained by record linkage with MIMS, the population-based province-wide immunization registry. RESULTS Overall, the adjuvanted H1N1 vaccine was 86% (95%CI 75-93%) effective in preventing laboratory-confirmed H1N1 infections when vaccination occurred ≥14 days before testing. Effectiveness seemed lower among older (≥50 years) individuals [51% (-51 to 84%)] and among those with immunocompromising conditions [67% (-13 to 90%)]. There was also evidence that the H1N1 vaccine might be less effective among those who had received the 2009/10 TIV. DISCUSSION The adjuvanted H1N1 vaccine used during Manitobas H1N1 mass vaccination campaign was highly effective against laboratory-confirmed pandemic H1N1 infection, especially among children and younger adults.

Prevalence and incidence of ischemic heart disease in multiple sclerosis: A population-based validation study

BACKGROUND Studies suggest an altered risk of ischemic heart disease (IHD) in multiple sclerosis (MS), but data are limited. We aimed to validate and apply administrative case definitions to estimate the incidence and prevalence of IHD in MS. METHODS Using administrative data we identified persons with incident MS (MSPOP) and a matched general population (GPOP) cohort. We developed case definitions for IHD using ICD-9/10 codes and prescription claims, compared them to medical records, then applied them to evaluate the incidence and prevalence of IHD. RESULTS Agreement between medical records and the administrative definition using ≥1 hospital or ≥2 physician claims over 5 years was moderate (kappa=0.66; 95% CI: 0.42-0.90). In 2005, the age-standardized prevalence of IHD was 6.77% (95% CI: 5.48-8.07%) in the MSPOP and 6.11% (95% CI: 5.56-6.66%) in the GPOP. The prevalence of IHD was higher in the MSPOP than the GPOP among persons aged 20-44 years (prevalence ratio 1.87; 95% CI: 1.65-2.12) and aged 45-59 years (prevalence ratio 1.21; 95% CI: 1.08-1.35). The incidence of IHD was also higher in the MSPOP (incidence rate ratio 1.24; 95% CI: 0.97-1.59). CONCLUSIONS More than 5% of the MSPOP has IHD. The incidence of IHD was higher than expected in persons aged <60 years. Further evaluation of this issue is warranted.

Direct costs of fractures in Canada and trends 1996-2006: a population-based cost-of-illness analysis.

Cost‐of‐illness (COI) analysis is used to evaluate the economic burden of illness in terms of health care resource (HCR) consumption. We used the Population Health Research Data Repository for Manitoba, Canada, to identify HCR costs associated with 33,887 fracture cases (22,953 women and 10,934 men) aged 50 years and older that occurred over a 10‐year period (1996–2006) and 101,661 matched control individuals (68,859 women and 32,802 men). Costs (in 2006 Canadian dollars) were estimated for the year before and after fracture, and the change (incremental cost) was modeled using quantile regression analysis to adjust for baseline covariates and to study temporal trends. The greatest total incremental costs were associated with hip fractures (median