Biomedical subjects

A Wajda

Publications and source records attributed to A Wajda.

22 records · Page 2Linked to original sources

PubMed1987

Simplifying record linkage: software and strategy.

Although the methodology of record linkage is fairly well developed, there is a need for less expensive methods and simpler software to facilitate trying out different tactics to generate good linkages. The present work has built on a fourth generation language SAS (Statistical Analysis System) with accompanying macroprocessor, to develop a user-friendly and flexible system for both exact and probabilistic matching. The major features of the LINKS system are presented and illustrated using 1979-1984 information from the Manitoba Health Services Commission (MHSC) registry file with the Canadian Mortality Data Base. Initial runs with exact, then probabilistic, matching linked approximately 91% of the Vital Statistics records to corresponding MHSC records. Subsequent modification of parameters improved the linkage to 95%.

Database Management Systems↗

PubMed1986

The art and science of record linkage: methods that work with few identifiers.

Increasing use of administrative records for research purposes has led to the need to develop methods for linking records. Linkage of the data from the Manitoba Health Services Commission (MHSC) with Canadian Vital Statistics records was done to verify Manitoba deaths, to measure degree of agreement between the two data sets, and to link "cause of death" information from Vital Statistics back to medical histories. A multi-stage approach to matching was adopted. Individual records matching perfectly across a number of relevant variables in the two files were selected first, reducing the number of records going through the probability matching to manageable proportions. Overall, almost 96% of the MHSC records were well matched with Vital Statistics records. Both uses of the matched data and various ways to confirm data quality are discussed.

Humans↗

PubMed1986

Variations in physicians' hospitalization practices: a population-based study in Manitoba, Canada.

This paper uses claims data from a universal health care system to describe physicians' hospitalization styles after adjusting for case-mix characteristics of their primary patients. Patients were uniquely assigned to that physician (general or family practitioners, internist, general surgeon, or obstetrician/gynecologist) seen most frequently over each two two-year periods (1972-74 and 1974-76). Four indices were developed including: 1) percentage of primary patients hospitalized; 2) mean number of readmissions for such patients; 3) mean length of stay; and 4) total days of hospitalization per primary care patient (a summary measure combining the first three). Rates of admission, not length of stay, were shown to be strongly related to this summary measure. Marked variations in the hospitalization indices were observed across physicians; these variations cannot be explained by the health or sociodemographic characteristics of a physician's patients. Rural physicians practicing in areas with high bed-to-population ratios and low occupancy rates were particularly high users of hospitals. The economic implications of different practice styles are shown to be large; physicians who were high users of hospitals serve 27 per cent of the patients but their patients consume 42 per cent of the hospital days.

Adult↗

PubMedDate not supplied

Is there a role for surgery in the acute management of infective endocarditis? A decision analysis and medical claims database approach.

In the absence of good clinical evidence from a randomized trial, the authors performed a decision analysis to determine the potential value of early elective surgery (OPNOW) for patients with left-sided Staphylococcus aureus infective endocarditis. Initial impressions (before performance of decision analysis) and initial runs at the formal models using probability estimates derived from clinicians suggested that OPNOW (i.e., within a few days of starting antibiotics) offered no advantage over attempted medical cure (WAIT) (life expectancy: WAIT = 325 weeks; OPNOW = 255 weeks). Extensive sensitivity analyses identified critical variables that needed further empirical estimation. The Manitoba Health Services Commission database identified 127 incident cases of endocarditis between April 1, 1979, and March 31, 1985, enabling estimation of values for these critical variables. With these estimates, the early surgery strategy appeared much better than the previous analyses had suggested (life expectancy: WAIT = 208 weeks, OPNOW = 256 weeks). The authors believe that this approach of combining decision analysis with medical claims databases is useful as an alternative or precursor to randomized trials, especially where the resource requirements and logistic difficulties of performing randomized trials are great.

Adult↗