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L L Roos

Publications and source records attributed to L L Roos.

At least 37 records · Page 2Linked to original sources
PubMed1996

Surveillance of vaccine-related adverse events in the first year of life: a Manitoba cohort study.

This study used data from the population database through which the province of Manitoba, Canada, administers its universal health insurance plan. Enrollment, hospitalization, and immunization files from children born in the 1987-1989 period were linked using the unique identification number assigned to each population member. Analysis of these linked data successfully identified serious potential adverse events in the first year of life and the timing of events around immunization. Not only is population-based active surveillance for immunization-related events feasible, but the techniques described, applied to years of data accumulated through surveillance, offer powerful research tools. Baseline population incidences of adverse events were calculated, temporal relationships between events and immunization assessed, and incidences for events showing true temporal associations determined. Eventual goals are the quantification of vaccine-related risk and the gathering of evidence concerning casual associations. The approach could be used readily by several other Canadian provinces and by health maintenance organizations in the United States.

Cohort Studies↗
PubMed1996

Reminding and monitoring: new uses of administrative data for preventive care.

This article illustrates how administrative data can be used to improve population health in an environment of fiscal constraint. In our universal single-payer health system, health care providers submit standardized data. This allows provinces to create health information utilities that generate population-based data that can be used for research and health care delivery. Although more study is needed to determine the cost-effectiveness of using such data to raise the rates of primary and secondary prevention, it appears that appropriately designed information systems could improve population health with relatively little additional cost.

Aged↗
PubMed1996

Hospitalization for acute pyelonephritis in Manitoba, Canada, during the period from 1989 to 1992; impact of diabetes, pregnancy, and aboriginal origin.

Population-based rates of hospitalization for acute pyelonephritis were estimated over 3 years with use of provincial administrative data on health care. Retrospective review of records of ICD9-CM discharge codes of pyelonephritis and urinary infection was performed in two acute care institutions to validate the discharge diagnosis; 80% of patients with a discharge diagnosis of pyelonephritis and 7% to 20% of patients with a discharge diagnosis of urinary infection met clinical criteria for admission for acute pyelonephritis. Mean rates of hospitalization +/- SD for acute pyelonephritis were 10.86 +/- 0.51 per 10,000 population among women and 3.32 +/- 0.27 per 10,000 population among men. From 18% to 31% of hospitalized women aged 20-39 years pregnant; 36% of 797 hospitalized women and 21% of 402 hospitalized men 40 years of age or older were diabetic. The hospitalization rates among Native American women with treaty status were five to 20 times greater than those among other women, which was partially attributable to a significantly greater frequency of pregnancy and diabetes in the former women. Hospitalization for acute pyelonephritis is common, and pregnancy and diabetes contribute substantially to hospitalization rates. The increased hospitalization rate among Native American women with treaty status is not fully explained by pregnancy or diabetes.

Acute Disease↗
PubMed1996

Short-term mortality after repair of hip fracture. Do Manitoba elderly do worse?

This article uses administrative data from Manitoba and New England to address the reasons underlying Manitoba's relatively high mortality in the 30 days after hip fracture repair. Both the Manitoba and New England data sets are population based, containing information on individuals 65 years of age or older in Manitoba (1979-1992; n = 10,007) and New England (1984-1985); n = 16,206). Various logistic regression models were estimated on pooled and separate data from Manitoba and New England; the models all showed similar predictive accuracy, having C statistics in the .71 to .74 range. Manitoba postsurgical 30-day mortality rates were greater than the 1984 to 1985 New England rate for each of the 14 years considered. In particular, New England residents with very short waits before hip fracture repair (0 or 1 day) had mortality rates both markedly lower than expected and significantly less than those of Manitobians with such short waits. Attention to the Manitoba hospitals with very poor 30-day survival and to the process surrounding selection of patients for early versus late surgery in Manitoba are clearly in order. The extent to which longer-term survival reflects 30-day survival also is discussed. Our findings highlight the utility of comparative data for understanding quality of care problems within a single region.

Aged↗
PubMed1996

Record linkage strategies, outpatient procedures, and administrative data.

By understanding the range of approaches implicit in modern record linkage, epidemiologists and health services researchers can better decide its suitability for their needs. The authors discuss a small record linkage project, providing a sense of where mistakes were made. The research first uses existing identification numbers as a gold standard for linking hospital abstracts and physician claims to investigate whether or not coronary angiography was performed on a given individual. Even if identification numbers are not available, a successful linkage (with more than 95% of the cases matched) may be possible under some circumstances. The linkage process highlights problems with the consistent recording of coronary angiography in inpatient and outpatient hospital abstracts. Our approach should prove useful when the same procedure is recorded in more than one place on a single file and when validating a procedure (or other event) across files is important. Given the growing number of health care databases and ongoing changes in the delivery of care, record linkage often can provide quality control and expand research opportunities in a timely fashion.

Abstracting and Indexing↗
PubMed1996

Population health and health care use: an information system for policy makers.

University-based researchers in Manitoba, Canada, have used administrative data routinely collected as part of the national health insurance plan to design a population-based health information system (POPULIS). Decision-makers can use this system to make critical comparisons across regions of residents' health status, socioeconomic risk characteristics, and use of hospitals, nursing homes, and physicians. Policy makers have found this information system useful in providing answers to questions they are often asked: 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? Three commentaries follow.

Database Management Systems↗
PubMed1995

Regionalization of cardiac surgery in the United States and Canada. Geographic access, choice, and outcomes.

OBJECTIVE: To determine how regionalization of facilities for coronary artery bypass surgery (CABS) affects geographic access to CABS and surgical outcomes. DESIGN: Computerized hospital discharge records were used to measure hospital CABS volume and in-hospital post-CABS mortality rates. Relationships between surgical volume and age- and sex-adjusted mortality rates were compared using chi 2 tests. Small-area analysis of the association between CABS rates and distances to nearest CABS hospital was performed using multivariate linear regression methods. SETTING: All nonfederal hospitals in New York, California, Ontario, Manitoba, and British Columbia. PATIENTS: All adult residents of the five jurisdictions who underwent CABS in a hospital in their jurisdiction from 1987 through 1989. RESULTS: In New York and Canada, approximately 60% of all CABS operations took place in hospitals performing 500 or more CABS operations per year, compared with only 26% in California. The highest mortality rates were found among California hospitals performing fewer than 100 CABS operations per year (adjusted 14-day in-hospital mortality was 4.7% compared with 2.4% in high-volume California hospitals, P < .001). The percentage of the population residing within 25 miles of a CABS hospital was 91% in California, 82% in New York, and less than 60% in Canada. Eliminating very low-volume (< 100 cases per year) CABS hospitals in California would increase travel distances to a CABS hospital only slightly for a small number of residents. The Canadian degree of regionalization was not associated with lower CABS rates within provinces for populations living at more remote distances from the nearest CABS hospital. CONCLUSION: Regionalization of CABS facilities in New York and Canada largely avoids the problem of low-volume outlier hospitals with high postoperative mortality rates found in California. New York has avoided the redundancy of facilities that exists in California while still providing residents a geographically convenient selection of CABS hospitals. Stricter regionalization in Canada may leave residents with a more narrow choice of facilities, but does not disproportionately affect access to surgery for populations living at remote distances from CABS facilities.

Canada↗
PubMed1995

The Population Health Information System: data analysis and software.

This article describes the software developed in the process of creating the Population Health Information System. The software can be applied to a range of administrative data and provides standardized data on the health status and health care use of populations by generating population-based rates of discrete events. The standardized approach permits construction of a comprehensive, comparative picture for residents of defined geographic regions. The addition of a user friendly graphic interface will permit regional planners to do their own data analyses and allow out-of-province researchers to adopt the system for their own uses.

Community Health Planning↗
PubMed1995

Changes in asthma severity in Manitoba.

OBJECTIVE: To assess changes in the severity of physician-diagnosed asthma between 1983 and 1988. DESIGN: Cross-sectional studies examining the frequency of markers of asthma severity: hospitalizations, ICU admissions, hospital emergency department visits, multiple physician contacts, and referrals to specialists in patients aged 0 to 14 years, 14 to 34 years, and > or = 35 years separately. SETTING: Physicians' claims data from the universal Provincial Health Insurance Plan for fiscal years 1983 and 1988. PATIENTS: All patients with the diagnosis of asthma, bronchitis, and COPD identified from the Manitoba Health database. MEASUREMENTS: The markers of severity were related to the prevalence of patients seeing a physician and receiving a diagnostic label of asthma, COPD, or bronchitis. RESULTS: The number of patients with physician-diagnosed asthma increased by 36.4% over the 5 years. In 1983, 11% of asthmatics were hospitalized during the year and 8% were hospitalized in 1988 (-2.5%; 95% confidence interval [CI], -3.2 to -1.8%). During both years, about 75% of the patients hospitalized were in hospital once only. Mean and median duration of hospital stay declined. The percentage of asthmatics seen in the hospital emergency departments declined slightly in all age groups, the total being 21% in 1983 and 18% in 1988 (-3.5%; 95% CI, -4.5 to -2.5%). About one third of the patients with asthma were seen only once by a physician during both of the years examined, 43 to 45% of them being seen on three or more occasions during both years. Referrals to specialists for all asthmatics increased from 12 to 14% (1.9%; 95% CI, 1.0 to 2.8%) from 1983 to 1988. This was almost entirely due to an increase from 11 to 16% (5.1%; 95% CI, 4.0 to 6.2%) in the youngest age group, an increase not accompanied by an increase in any other marker of severity. Changes in asthma severity were similar to changes in the severity in patients with bronchitis and COPD. CONCLUSION: No increase in severity of asthma was seen between 1983 and 1988, but the prevalence of the diagnostic label of asthma increased substantially.

Adolescent↗
PubMed1995

A population-based approach to monitoring adverse outcomes of medical care.

A population-based approach to monitoring quality of care combining small-area analysis and outcomes assessment is proposed. While adverse outcomes due to poor surgical technique have long been targeted for quality-of-care review, in this study, giving similar attention to adverse outcomes produced by high rates of interventions is proposed. A population-based approach will strengthen traditional review efforts that currently begin and end at the hospital door. Excluded from these reviews have been questions such as the following: Should the procedure have been performed in the first place? Did the benefits outweigh the risks? Were there other patients not operated on who might have benefited more? Traditional approaches can identify less competent hospitals or practitioners: population-based approaches can identify the surgical enthusiasts who may pose equal risks to the populations of the areas they serve. Applying a population-based approach to review of coronary artery bypass graft surgery for Medicare patients in five cities in the United States demonstrates that at least as many deaths could have been prevented by decreasing surgical rates to the U.S. average as by improving the technical quality of care with which the procedure was performed. A similar population-based analysis of complications (as judged by re-admissions within 30 days of surgery) associated with hysterectomy across regions of Manitoba, Canada, is presented. In summary, negligent acts in the delivery of health care in institutions are rare and are difficult to detect because medicine is an inexact science and because adverse outcomes are more likely in high-risk patients, regardless of the quality of care. However, from a population perspective, adverse events are predictable, occur relatively frequently, and are directly related to the frequency of a population's exposure to surgical intervention. Efforts to improve quality of care could be made more effective by including the rates at which populations are exposed to treatments and the technical quality of care delivered.

Adult↗
PubMed1994

Comparing standardized rates of events.

This paper reviews issues associated with testing a null hypothesis of the equality of, and generating descriptive statistics for, standardized rates of events--recurrent or non-recurrent. The variance estimation for rates of surgical procedures, hospitalizations, and health care expenditures is discussed in the context of small area analysis. The proposed approach for estimating the variance of standardized rates is independent of assumptions about the underlying distribution of rates, is widely applicable, and seems preferable to approaches derived under special, but uncertain, parametric assumptions. A statistic is suggested based on person-level data, which allows comparing both rates of events and variation in rates between independent groups. The proposed statistic does not depend on the underlying unknown distribution of the events and does not require restrictive assumptions such as equal variances among the competing rates.

Analysis of Variance↗
PubMed1994

A comparison of administrative versus clinical data: coronary artery bypass surgery as an example. Ischemic Heart Disease Patient Outcomes Research Team.

Health services researchers rely heavily on administrative data bases, but incomplete or incorrect coding may bias risk models based on administrative data. The best method for validating administrative data is to collect detailed information about the same cases from independent sources, but this approach may be too costly or technically difficult. We used data on coronary artery bypass surgery from four sites (Duke University; Minneapolis--St Paul; California; and Manitoba) to demonstrate an alternative approach for assessing diagnostic coding and to explore the implications of miscoding. The first two sites have clinical data; the second two have administrative data. The prevalences of 14 comorbidities and the associated risk ratios for short-term mortality were compared across data sets. Some comorbidities could not be precisely mapped to ICD-9-CM. Chronic or asymptomatic conditions such as mitral insufficiency, cardiomegaly, previous myocardial infarction, tobacco use, and hyperlipidemia were far less prevalent in administrative data than in clinical data. The prevalence of diabetes, unstable angina, and congestive heart failure were similar in administrative and clinical data. Estimates of relative risk derived from clinical data equalled or surpassed those derived from administrative data for all conditions. Hospitals should be encouraged to improve reporting of coexisting conditions on discharge abstracts and claims. In the meantime, researchers using administrative data should assess the vulnerability of their risk models to bias caused by selective underreporting.

Adult↗
PubMed1994

Monitoring childhood immunizations: a Canadian approach.

In Manitoba, Canada, a centralized, computerized childhood immunization monitoring system serves a population with insured medical coverage; each individual has a unique identification number. All physicians bill a single payer, and specific billing codes are used to identify immunizations given by physicians and by public health nurses. Together with dates of service, this information is used to construct immunizations-to-date and age-at-immunization profiles for individuals and groups. Reminders seeking missing information are built into the system and executed at strategic ages. The quality of input data has been assessed as high. The approach could be used readily by health maintenance organizations in the United States.

Child↗
PubMed1993

Clinical effectiveness of influenza vaccination in Manitoba.

OBJECTIVE: To assess the clinical effectiveness of influenza vaccination in preventing influenza-associated hospitalization and death. DESIGN: Case-control study. SETTING AND PATIENTS: Noninstitutionalized persons aged 45 years or older living in Manitoba, on December 1, 1982, and December 1, 1985. METHODS: Linked records of the Manitoba population registry, hospital-discharge abstracts, physician claims for ambulatory-patient visits and influenza vaccination, and vital statistics were used. A matched-set analysis estimated the clinical effectiveness of influenza vaccination in preventing hospital admissions and deaths from influenza-associated conditions during influenza A (H3N2) outbreak periods in 1982 to 1983 (12 weeks) and 1985 to 1986 (10 weeks). The analysis adjusted for hospital discharge and ambulatory care for high-risk conditions within the previous 15 months and 3 months, respectively. RESULTS: Influenza vaccination prevented 32% to 39% of hospital admissions with pneumonia and influenza and 15% to 34% of admissions with all respiratory conditions. Vaccination was 43% to 65% effective in preventing hospital deaths with these conditions (all listed diagnoses) and 27% to 30% effective in preventing deaths from all causes. CONCLUSION: Influenza vaccination has substantial clinical effectiveness in preventing hospital admission and death from influenza-associated conditions in noninstitutionalized individuals.

Aged↗
PubMed1993

Use of coronary artery bypass surgery in the United States and Canada. Influence of age and income.

OBJECTIVE: To compare overall rates of coronary artery bypass surgery (CABS) in several Canadian and US jurisdictions and to compare use by age and income groups in the two countries. DESIGN: Survey, using computerized hospital discharge abstracts. SETTING: All nonfederal hospitals in New York, California, Ontario, Manitoba, and British Columbia between 1983 and 1989. PATIENTS: All adult residents of the five jurisdictions who underwent CABS in a hospital in their jurisdiction. RESULTS: Between 1983 and 1989, the CABS rates were consistently highest in California and lowest in the Canadian jurisdictions. In 1989, the age-adjusted rate of CABS in California (112.5/100,000 adults) was 27% higher than in New York (88.4/100,000) and 80% higher than in the three Canadian provinces combined (62.4/100,000). The CABS rates increased for those aged 65 years and older and decreased for those aged 20 to 54 years in all five jurisdictions. In 1989, CABS rates were three times higher in California than in Canada for those aged 75 years and older, and the higher rates for those aged 65 years and older accounted for 75% of the overall difference in rates between California and Canada. In Canada, CABS rates for the nonelderly varied little by income of area of residence, but in New York and California, rates increased steadily with the income of area of residence. CONCLUSION: Control over the supply of resources in Canada is associated with markedly lower CABS rates for the elderly than found in the United States. While overall rates are lower in Canada, the Canadian universal health insurance system reduces the influence of income on access to CABS found in the United States. However, even without universal health insurance, CABS rates for the nonelderly living in the poorest areas in California are similar to the rates for those living in the poorest parts of Canada.

Adult↗
PubMed1993

Registries and administrative data: organization and accuracy.

In this article the organization and accuracy of the population registry and administrative data base in Manitoba, Canada are discussed. The overall data management strategy and a framework for analyzing the accuracy of such data are presented. The generally high quality of the Manitoba registry file (necessary to track individuals over time) and the hospital claims is supported by comparisons with other data sources. Hospital claims' main quality problems concern the reliability of certain secondary diagnoses and the level of aggregation necessary for reasonable agreement with other data collection methods (such as chart reviews). Finally, some of the research possibilities associated with population registries and administrative data are outlined.

Adolescent↗