The association of objectively ascertained sibling fracture history with major osteoporotic fractures: a population-based cohort study.

We investigated the association of objectively ascertained sibling fracture history with major osteoporotic fracture (hip, forearm, humerus, or clinical spine) risk in a population-based cohort using administrative databases. Sibling fracture history is associated with increased major osteoporotic fracture risk, which has implications for fracture risk prediction. INTRODUCTION: We aimed to determine whether objectively ascertained sibling fracture history is associated with major osteoporotic fracture (MOF; hip, forearm, humerus, or clinical spine) risk. METHODS: This retrospective cohort study used administrative databases from the province of Manitoba, Canada, which has a universal healthcare system. The cohort included men and women 40+ years between 1997 and 2015 with linkage to at least one sibling. The exposure was sibling MOF diagnosis occurring after age 40 years and prior to the outcome. The outcome was incident MOF identified in hospital and physician records using established case definitions. A multivariable Cox proportional hazards regression model was used to estimate the risk of MOF after adjustment for known fracture risk factors. RESULTS: The cohort included 217,527 individuals; 91.9% were linked to full siblings (siblings having the same father and mother) and 49.0% were females. By the end of the study period, 6255 (2.9%) of the siblings had a MOF. During a median follow-up of 11 years (IQR 5-15), 5235 (2.4%) incident MOF were identified in the study cohort, including 234 hip fractures. Sibling MOF history was associated with an increased risk of MOF (hazard ratio [HR] 1.67, 95% confidence interval [CI] 1.44-1.92). The risk was elevated in both men (HR 1.57, 95% CI 1.24-1.98) and women (HR 1.74, 95% CI 1.45-2.08). The highest risk was associated with a sibling diagnosis of forearm fracture (HR 1.81, 95% CI 1.53-2.15). CONCLUSION: Sibling fracture history is associated with increased MOF risk and should be considered as a candidate risk factor for improving fracture risk prediction.

Effect of Study Duration and Outcome Measurement Frequency on Estimates of Change for Longitudinal Cohort Studies in Routinely-Collected Administrative Data.

INTRODUCTION: When designing longitudinal cohort studies, investigators must make decisions about study duration (i.e. length of follow-up) and frequency of outcome measurement. This research explores these design decisions for longitudinal cohort studies constructed using routinely-collected administrative data. OBJECTIVES: To illustrate the effects of varying study duration and frequency of outcome measurement in longitudinal cohort studies conducted using routinely-collected administrative data using a numeric example. METHODS: Linked administrative data from Manitoba, Canada were used. The cohort included mothers who experienced the death of an infant between April 1, 1999 and March 31, 2012 and a matched (three:one) group of mothers who did not experience an infant death. A generalized linear model was used to test for differences between groups in the non-linear (i.e. quadratic) and linear trend over time for the number of healthcare contacts. Holding sample size constant, models were fit to the data for various combinations of study duration and measurement frequency. Regression coefficient estimates and their standard errors were compared. RESULTS: A total of 2576 mothers were included; 644 experienced an infant death and 1932 were matches. Thirteen combinations of measurement frequency (one, two, three, four periods/year) and study duration (one, two, three, four years) were investigated. As frequency increased from one to four periods/year, the standard errors of the regression coefficients for the group difference in the non-linear trend (i.e. group-time-time interaction) decreased up to 98.9%. As duration increased from one to fours years, the standard errors decreased up to 96.9%. As frequency and duration increased, the estimated regression coefficients trended toward zero. Similar results were observed for the linear trend model. CONCLUSION: Longitudinal cohort studies based on administrative data offer flexibility in time-related design elements, but present potential challenges. Recommendations about how to select and report design decisions in studies should be included in reporting guidelines.

The Concept Dictionary and Glossary at MCHP: Tools and Techniques to Support a Population Research Data Repository.

The Manitoba Centre for Health Policy's Concept Dictionary and Glossary, and the Data Repository they document, broaden the analytic possibilities associated with administrative data. The aim of the Repository is to describe and explain patterns of health care and illness, while the Concept Dictionary and Glossary create consistency in documenting research methodologies. The Concept Dictionary alone contains detailed operational definitions and programming code for measures used in MCHP research that are reusable in future projects. Making these tools available on the internet allows reaching a heterogeneous audience of academic and government health service partners, epidemiologists, planners, programmers, clinicians, and students extending around the globe. They aid in the retention of corporate knowledge, facilitate researcher/analyst communication, and enhance the Centre's knowledge translation activities. Such documentation has saved countless hours for programmers, analysts and researchers who frequently need to tread paths previously taken by others.

A framework for modelling differences in regional mortality over time.

STUDY OBJECTIVE: To present a conceptual framework for testing differences in mortality for small geographical areas over time using the generalised linear model with generalised estimating equations. This framework can be used to test whether the magnitude of regional inequalities in health status has changed over time. DESIGN: A Poisson regression model for correlated data is used to investigate the relation of population health status to demographic, geographical, and temporal explanatory variables. Differences between regions at one or more points in time are tested with linear contrasts. SETTING AND PARTICIPANTS: A case example shows the application of the framework. All cause mortality and cause specific mortality were compared for three rural regions of Manitoba, Canada between 1985 and 1999. The data were obtained from Vital Statistics records and the provincial health registry. MAIN RESULTS: Tests of linear contrasts on the regression coefficients for time and region show an increase in the magnitude of the difference in the risk of all cause mortality and heart disease mortality between northern and southern regions of the province for the 1985-1989 and 1995-1999 time periods. No significant differences are identified for cancer, injury, or respiratory disease mortality. CONCLUSIONS: The proposed framework enables testing of a variety of hypotheses about differences between regions and time periods and can be applied to other measures of population health status.

Spirometry and obstructive lung disease in Manitoba.

BACKGROUND: Spirometry, the measurement of forced expiratory volume in 1 s and forced vital capacity, is recommended in the diagnosis and management of the obstructive lung diseases asthma and chronic obstructive pulmonary disease (COPD). The present report describes spirometry use in Manitoba and tests the hypothesis that regional spirometry use correlates with the prevalence of physician-diagnosed obstructive lung diseases. METHODS: Spirometry is renumerated on a fee-for-service basis by Manitoba Health. Like other physician services, billing data include a diagnosis, patient identifiers, as well as the patient's sex, date of birth and residential postal code. Physician billings for spirometry for 1991 to 1998 were analyzed, comparing data with billings for physician visits for obstructive diseases. Four age groups were examined, as were income quintiles in Winnipeg, Manitoba. In addition, the prevalence of physician-diagnosed obstructive diseases were compared with spirometry rates in 49 service use areas of the province. RESULTS: Annually, about 3% of the Manitoba population underwent spirometry, and in aggregate, about 14% underwent spirometry during the eight years of the study. Rates in Winnipeg were higher than in the remainder of the province. Spirometry rates did not increase with time, and people who underwent spirometry had 1.4 to 1.7 tests/year. In children, higher income quintiles were tested more than lower income quintiles, while in adults, income quintiles were tested with equal frequency. People with obstructive lung disease accounted for about 75% of those tested, and in people with these diagnoses, the likelihood of testing increased approximately linearly with the number of physician visits for asthma or COPD. Children with asthma were tested less often than adults, and adults with asthma or both asthma and COPD were tested more often than those with COPD alone. In adults with asthma or asthma and COPD who had more than 10 physician visits for these diagnoses, testing rates were more than 70%, and multiple tests were common. In patients labelled with COPD only and with more than 20 physician visits, about one-third did not undergo spirometry. In children aged five to 14 years and in adults 15 to 44 years old, regional spirometry rates correlated well with regional asthma rates. Regional spirometry rates also correlated significantly with regional rates of asthma and/or COPD in people older than 34 years old. INTERPRETATION: Spirometry use is considerably higher in patients with asthma than in patients with COPD, suggesting that guidelines are followed more closely in patients with asthma, and that many patients are labelled with COPD without appropriate documentation. Spirometry use is apparently indicative of physician interest in the problem of obstructive lung diseases.

Epidemiology of varicella zoster virus infection in Canada and the United Kingdom.

Many countries are currently studying the possibility of mass vaccination against varicella. The objective of this study was to provide a comprehensive picture of the pre-vaccine epidemiology of the varicella zoster virus (VZV) to aid in the design of immunization programs and to adequately measure the impact of vaccination. Population-based data including physician visit claims, sentinel surveillance and hospitalization data from Canada and the United Kingdom were analysed. The key epidemiological characteristics of varicella and zoster (age specific consultation rates, seasonality, force of infection, hospitalization rates and inpatient days) were compared. Results show that the overall epidemiology of varicella and zoster is remarkably similar between the two countries. The major difference being that, contrary to Canada, the epidemiology of varicella seems to be changing in the United Kingdom with an important decrease in the average age at infection that coincides with a significant increase in children attending preschool. Furthermore, differences exist in the seasonality between the United Kingdom and Canada, which seem to be primarily due to the school calendar. These results illustrate that school and preschool contact patterns play an important role in the dynamics of varicella. Finally, our results provide baseline estimates of varicella and zoster incidence and morbidity for VZV vaccine effectiveness and cost-effectiveness studies.

Monitoring health reform: a report card approach.

UNLABELLED: During the past several years, budget cuts have forced hospitals in several countries to change the way they deliver care. Gilson (Gilson, L. (1998). DISCUSSION: In defence and pursuit of equity. Social Science & Medicine, 47(12), 1891-1896) has argued that, while health reforms are designed to improve efficiency, they have considerable potential to harm equity in the delivery of health care services. It is essential to monitor the impact of health reforms, not only to ensure the balance between equity and efficiency, but also to determine the effect of reforms on such things as access to care and the quality of care delivered. This paper proposes a framework for monitoring these and other indicators that may be affected by health care reform. Application of this framework is illustrated with data from Winnipeg, Manitoba, Canada. Despite the closure of almost 24% of the hospital beds in Winnipeg between 1992 and 1996, access to care and quality of care remained generally unchanged. Improvements in efficiency occurred without harming the equitable delivery of health care services. Given our increasing understanding of the weak links between health care and health, improving efficiency within the health care system may actually be a prerequisite for addressing equity issues in health.

Health reform and technological change: shifting hospitalization patterns for four procedures in Manitoba.

This study used Manitoba data from 1991 to 1996 to assess the effects of health reforms and technological advances on hospitalization patterns, patient mortality, and readmission rates. Cholecystectomy and hernia repair served as indicators of response to both new technology and health reforms, while appendectomy and hysterectomy helped gauge the impact of health reforms alone. Neither the introduction of new technology (i.e. laparoscopy) nor the health reform initiatives (i.e. shorter hospital stays) adversely affected surgical volumes, postsurgical mortality, or postsurgical readmissions.

Health care seeking behavior following a health survey: impact on prevalence estimates of chronic diseases.

This article addresses the time sequence between a population health survey and subsequent health care use and how this changes the incidence estimates of selected chronic diseases. A cardiovascular survey of a representative sample of the adult population of Manitoba, Canada was linked with the health insurance claims database. Of the 2792 subjects in the survey, 98% were linked successfully, using an encrypted personal health insurance number. Five years of physician claims data for the survey participants were reviewed including 18 months prior to and 42 months following the survey. Survey participants started seeking confirmation of possible hypertension as soon as they received blood pressure information at the interview. Confirmation of diabetes and elevated cholesterol were not completed until 3-4 months after participants had received the laboratory test results. As many as 4.6 times more new cases of hypertension per month, 5.1 times more cases of elevated cholesterol, and 3.3 times more cases of diabetes were diagnosed following the survey. Surveys designed to determine the prevalence of specific chronic diseases generate new cases within a short time afterwards, thus affecting the original prevalence estimates. The process of assessing the burden of disease in a population is dynamic rather than static, and comparisons across populations need to take into account the frequency and recency of past surveys.

Across time and space: variations in hospital use during Canadian health reform.

OBJECTIVES: To investigate change in hospital utilization in a population and to discuss analytical strategies using large administrative databases, focusing on variations in rates of different types of hospital utilization by income quintile neighborhoods. DATA SOURCES: Hospital discharge abstracts from Manitoba Health, used to study the changes in utilization rates over eight fiscal years (1989-1996). STUDY DESIGN: We test the hypotheses that health reform has changed utilization rates, that utilization rates differ significantly across income quintiles (defined by the relative affluence of neighborhood of residence), and that these variations have been maintained over time. Our approach uses generalized estimating equations to produce robust and consistent results for studying rates of recurrent and nonrecurrent events longitudinally. DATA EXTRACTION METHODS: Rates of individuals hospitalized, hospital discharges, days of hospitalization, and hospitalization for different types of medical conditions and surgical procedures are generated for the period April 1, 1989 through March 31, 1997 for residents of Winnipeg, Manitoba. Data are grouped according to the individual's age, gender, and neighborhood of residence on April 1 of each of the eight fiscal years for the rate calculations. Neighborhood of residence and the 1991 Canadian Census public use database are used to assign individuals to income quintiles. PRINCIPAL FINDINGS: The substitution of outpatient surgery for inhospital surgery accounted for much of the change in hospital utilization over the 1989-1996 period. Health care reform did not have a significant effect on the utilization gradient already observed across socioeconomic groups. Health reform markedly accelerated declines in in-hospital utilization. CONCLUSIONS: Grouping the data with key characteristics intact facilitates the statistical analysis of utilization measures previously difficult to study. Such analyses of variations across time and space based on parametric models allows adjustment for continuous covariates and is more efficient than the traditional nonparametric approach using standardized rates.

Multiple approaches to assessing the effects of delays for hip fracture patients in the United States and Canada.

OBJECTIVE: To examine the determinants of postsurgery length of stay (LOS) and inpatient mortality in the United States (California and Massachusetts) and Canada (Manitoba and Quebec). DATA SOURCES/STUDY SETTING: Patient discharge abstracts from the Agency for Health Care Policy and Research Nationwide Inpatient Sample and from provincial health ministries. STUDY DESIGN: Descriptive statistics by state or province, pooled competing risks hazards models (which control for censoring of LOS and inpatient mortality data), and instrumental variables (which control for confounding in observational data) were used to analyze the effect of wait time for hip fracture surgery on postsurgery outcomes. DATA EXTRACTIONS: Data were extracted for patients admitted to an acute care hospital with a primary diagnosis of hip fracture who received hip fracture surgery, were admitted from home or the emergency room, were age 45 or older, stayed in the hospital 365 days or less, and were not trauma patients. PRINCIPAL FINDINGS: The descriptive data indicate that wait times for surgery are longer in the two Canadian provinces than in the two U.S. states. Canadians also have longer postsurgery LOS and higher inpatient mortality. Yet the competing risks hazards model indicates that the effect of wait time on postsurgery LOS is small in magnitude. Instrumental variables analysis reveals that wait time for surgery is not a significant predictor of postsurgery length of stay. The hazards model reveals significant differences in mortality across regions. However, both the regressions and the instrumental variables indicate that these differences are not attributable to wait time for surgery. CONCLUSIONS: Statistical models that account for censoring and confounding yield conclusions that differ from those implied by descriptive statistics in administrative data. Longer wait time for hip fracture surgery does not explain the difference in postsurgery outcomes across countries.

Organizing the present, looking to the future: an online knowledge repository to facilitate collaboration.

BACKGROUND: Comprehensive data available in the Canadian province of Manitoba since 1970 have aided study of the interaction between population health, health care utilization, and structural features of the health care system. Given a complex linked database and many ongoing projects, better organization of available epidemiological, institutional, and technical information was needed. OBJECTIVE: The Manitoba Centre for Health Policy and Evaluation wished to develop a knowledge repository to handle data, document research Methods, and facilitate both internal communication and collaboration with other sites. METHODS: This evolving knowledge repository consists of both public and internal (restricted access) pages on the World Wide Web (WWW). Information can be accessed using an indexed logical format or queried to allow entry at user-defined points. The main topics are: Concept Dictionary, Research Definitions, Meta-Index, and Glossary. The Concept Dictionary operationalizes concepts used in health research using administrative data, outlining the creation of complex variables. Research Definitions specify the codes for common surgical procedures, tests, and diagnoses. The Meta-Index organizes concepts and definitions according to the Medical Sub-Heading (MeSH) system developed by the National Library of Medicine. The Glossary facilitates navigation through the research terms and abbreviations in the knowledge repository. An Education Resources heading presents a web-based graduate course using substantial amounts of material in the Concept Dictionary, a lecture in the Epidemiology Supercourse, and material for Manitoba's Regional Health Authorities. Confidential information (including Data Dictionaries) is available on the Centre's internal website. RESULTS: Use of the public pages has increased dramatically since January 1998, with almost 6,000 page hits from 250 different hosts in May 1999. More recently, the number of page hits has averaged around 4,000 per month, while the number of unique hosts has climbed to around 400. CONCLUSIONS: This knowledge repository promotes standardization and increases efficiency by placing concepts and associated programming in the Centre's collective memory. Collaboration and project management are facilitated.

Delivering prevention: the role of public programs in delivering care to high-risk populations.

A successful program of prevention or early detection should have a high level of population coverage and should ensure that high-risk populations are targeted. In practice, relatively little attention has been paid to the tendency toward greater use of preventive care by populations at lower risk, in other words, for higher use by the wealthy than by the poor. Current delivery patterns of preventive care raise questions as to how to organize these services more effectively. Physician-based delivery of preventive care in a fee-for-service system seems to result in Canadian patterns of use that are fairly similar to those found in the United States. Universal free insurance alone does not appear to be enough to counteract the failure to target preventive care toward the least-healthy groups. Appropriately-run Canadian provincial programs may be able both to expand coverage and to target high-risk populations. The population coverage for three measures directed toward prevention or early detection--childhood immunization (which in Manitoba has been offered through a long-standing provincial program), screening mammography (a new provincial program), and cervical cancer screening (no provincial program)-are compared using longitudinal administrative data from Manitoba. The discussion emphasizes the role of provincial programs and the possibilities for using population-based data to help provide cost-effective care to high-risk populations.

Managing health services: how the Population Health Information System (POPULIS) works for policymakers.

OBJECTIVES: University-based researchers in Manitoba, Canada, have used administrative data routinely collected as part of the national health insurance plan to design an integrated database and population-based health information system. This information system is proving useful to policymakers for answering such questions as: Which populations need more physician services? Which need fewer? Are high-risk populations poorly served? or do they have poor health outcomes despite being well served? Does high utilization represent overuse? or is it related to high need? More specifically, this system provides decision makers with the capability to make critical comparisons across regions and subregions of residents' health status, socioeconomic risk characteristics and use of hospitals, nursing homes, and physicians. The system permits analyses of demographic changes, expenditure patterns, and hospital performance in relation to the population served. The integrated database has also facilitated outcomes research across hospitals and countries, utilization review within a single hospital, and longitudinal research on health reform. The discussion highlights the strengths of integrated population-based information in analyzing the health care system and raising important questions about the relationship between health care and health.

A research registry: uses, development, and accuracy.

Many studies of population health, clinical epidemiology, and health services can be supported by a population-based research registry. Such a registry accurately defines the health insurance status for each individual over many years, magnifying the effectiveness of a cross-sectional registry (typically relevant for only a short duration) used in the administration of a health insurance plan. A research registry can distinguish between "well" individuals (no contact with the health care system), loss to follow-up (ineligibility associated with leaving the insurance plan), loss of continuity (two or more unlinked registrations over time for the same person), and mortality. The Manitoba research registry was developed to facilitate longitudinal studies; working within strict confidentiality controls, identifiers for each individual known to Manitoba Health since 1970 can be retrieved and a single unique identifier assigned. Careful reporting of changes in family registration numbers has enabled tracing area of residence, marital status, and family characteristics; results are equivalent to a daily census of the province. This article provides details on source materials, design, and quality of the registry, highlighting its value both for the development of integrated population health information systems and for research in general.

Managing health services: how administrative data and population-based analyses can focus the agenda.

University-based researchers in Manitoba, Canada, have used administrative data routinely collected as part of the national health insurance plan to design an integrated database and population-based health information system. This information system is proving useful to policymakers for providing answers to such questions as: which populations need more physician services? Which need fewer? Are high-risk populations poorly served or do they have poor health outcomes despite being well served? Does high utilization represent overuse or utilization related to high need? More specifically, this system provides decision-makers with the capability to make critical comparisons across regions and subregions of residents' health status, socioeconomic risk characteristics, and use of hospitals, nursing homes, and physicians. The system permits analyses of demographic changes, expenditure patterns, and hospital performance in relation to the population served. The integrated database has also facilitated outcomes research across hospitals and counties, utilization review within a single hospital, and longitudinal research on health reform. A particularly interesting application to planning physician supply and distribution is discussed. The discussion highlights the strengths of integrated population-based information in analyzing the health care system and raising important questions about the relationship between health care and health.

Hepatitis B immunization in a low-incidence province of Canada: comparing alternative strategies.

This study provides a comparative cost-effectiveness analysis of three universal immunization programs for hepatitis B virus (HBV). Using three theoretical cohorts of infants, 10-year-olds, and 12-year-olds, a universal immunization program was compared with a prenatal screening/newborn immunization program involving testing of prepartum women and immunization of newborns of HBsAg-positive mothers. A Markov long-term outcome model used Manitoba data to estimate costs and health outcomes across the lifespan. The model was based on an HBV incidence rate of 19/100,000 and a discount rate of 5% and incorporated the most recent treatment advances (interferon therapy). Cost-effectiveness was calculated as the ratio of dollars spent per year of life saved, with costs determined from the perspective of a third-party payer. The universal infant-immunization program, although not cost-saving, was associated with a low, economically attractive cost-effectiveness ratio of $15,900 (Canadian) per year of life saved, a figure substantially lower than the ratios of $97,600 and $184,800 (Canadian) associated with the universal programs for 10- and 12-year-olds, respectively. Cost-effectiveness ratios were found to be sensitive to changes in immunization costs, HBV incidence rates, and the rate at which protective antibody levels are lost over time: If these variables move in the directions suggested by current trends, the authors anticipate an increasing economic appeal of universal programs well into the future. A universal program of HBV immunization for infants appears to be economically practical in regions where HBV infection rates are low and stable.