Classifying ethnicity utilizing the Canadian Mortality Data Base.

UNLABELLED: The study of ethnic differences in disease is a methodological challenge as ethnicity is often not identified in existing datasets and surrogate measures need to be used. We have developed a novel methodology combining last name and country of birth to study mortality patterns of Canadians of South Asian (SA) and Chinese (CH) ethnic origin and have compared death rates among SA, CH, and White (WH) Canadians. METHODS: SA and CH were identified in the Canadian Mortality Data Base (CMDB) using the last name and country of birth of the deceased. Records of people who had been born in countries with large South Asian and Chinese populations (e.g. India, Pakistan, China, Hong Kong) were selected and manually screened by last name. A name directory was then created of distinct South Asian and Chinese names and this directory was used to search all other records in the CMDB for SA and CH deaths. Where necessary, other identifying characteristics such as first name and parents' last name were also used. Population counts were obtained from the Census self-reported question on ethnicity for SA and CH. WH were identified as non-immigrant Canadians who were neither SA nor CH. The method of assigning ethnicity in the CMDB and Census were assessed for comparability and issues of validity and reliability were addressed. RESULTS: Using this method, 10,989 SA and 21,548 CH deaths were identified. There was marked heterogeneity in birthplace, with only 56% of SA born in South Asia and only 74% of CH born in Greater China. Last names had high validity for self-reported ethnicity in a population sample of SA and were highly reproducible. Mortality rates varied dramatically between groups studied. SA and WH had high rates of ischemic heart disease while stroke mortality was similar among all three groups. Cancer death rates were high in CH and WH and much lower in SA. CONCLUSION: Last names and country of birth can be used to determined ethnicity of SA and CH with validity and reliability, and leads to a more accurate classification than country of birth alone. The contrasting patterns observed in mortality from major causes of death suggest many interesting hypotheses for further study.

Person-based information from Canadian hospital discharge data.

Statistics summarizing Canadians' use of hospital services are usually based on simple discharge totals, without any attempt to distinguish which discharges may have belonged to the same person. This leads to a distorted view of the prevalence of illness and the resources required to serve each patient. Statistics based on the number of people going to hospital shed new light on the demand for resources by various groups, now and in the future.

An investigation of the increase in preschool-age asthma in Manitoba, Canada.

Asthma has long been a major cause of illness and disability among young Canadians. From 1970-71 to 1987-88, hospital admissions for asthma increased significantly among Canadian children under the age of fourteen. Many hypotheses may explain this increase in asthma prevalence. There could be a true increase in the number of people developing symptoms of the disease or increased asthma rates could be an artifact due to changes in detection, diagnosis, treatment, or coding. This study reviews hypotheses put forward to explain the increase in asthma prevalence, and tests some of them in Manitoba for children aged 0-4. Physician claims data and hospital separation data were merged to create unique person oriented medical records. These records were used to estimate the number of children seeking medical services for asthma during a five-year period (1984-85 to 1988-89) and the change in rates over this time period. From 1984-85 to 1988-89, both prevalence and incidence rates for children less than five years of age increased. Prevalence rates showed strong seasonal peaks in the spring and the fall. There is no indication that asthma increased in severity. The hospitalization rate (the number visiting a hospital for asthma divided by the total number seeking medical care for asthma), the average number of hospital admissions per year, and the average number of days spent in a hospital per year did not increase. Levels of ozone (O3) and nitrogen dioxide (NO2) in downtown Winnipeg increased over the study period and asthma prevalence increased twice as fast in Winnipeg as in the rest of the province. For Manitoba, the increase in preschool-aged asthma does not appear to be due to increased use of medical services, a change in ICD coding, an increase in the severity of the cases, or a decrease in income levels. The increases appear to be at least partly due to changes in diagnostic practices. The relationship between asthma and air pollution needs more detailed study as pollution is likely to be an important factor, particularly during the spring. Other areas for further investigation are changes in allergy and virus precursors, maternal smoking, and increased levels of pollens, molds and dust mites.

Coronary artery bypass surgery in Canada.

This report examines trends in the number and the rates of coronary artery bypass surgery (CABS) in Canada, performed over a six-year period from 1981-82 to 1986-87. The analysis includes comparisons of rates and events by sex, age and geographic location. In Canada 10,865 CABS were performed in 1986-87 representing a 39% increase over 1981-82. During the same period the rate of CABS rose to 43.2 per 100,000 population. In the twelve census metropolitan areas (CMAs) covered in this study, CABS increased 45.7% from 6,477 in 1981-82 to 9,439 in 1986-87, while hospital separations for Ischemic Heart Disease (IHD) increased by 22.6%. Regionally the coronary artery bypass surgery rate was lowest in Halifax at 62.4 per 100,000 population and highest in Ottawa-Hull at 131.8 per 100,000 population. The average annual proportion of CMAs ranged from 15.5% for residents in Halifax (84.5% for non-residents) to a high of 65.7% for residents in Montreal (34.3% for non-residents). Procedure rates increased consistently among the 65-74 and 75+ age groups, remained stable in the 55-64 age group, and decreased in the 35-54 age group. The variations among the CMAs may in part be due to the amount of resources available in each CMA, the demand for this type of service and perhaps to differing patterns of physician practice.

Acute myocardial infarction. A feasibility study using record-linkage of routinely collected health information to create a two-year patient profile. Manitoba, 1984-85 and 1985-86.

Manitoba's hospital separations and physician medical files were linked for the fiscal years 1984-85 and 1985-86. The result was a study file consisting of records for 5,293 males and 3,143 females, who, during this period, suffered an Acute Myocardial Infarction (AMI), commonly called a heart attack. Merging the two types of files created a comprehensive data base for these AMI victims. The Manitoba age-sex standardized AMI rate was 38.0 per 10,000 population. Age-specific rates were higher for males than for females for all age groups. Hospitalized cases accounted for 7,201 individuals or 85.4% of AMI victims. Age-sex standardized rates of hospitalization per 10,000 population ranged from 27.1 in the Central region to 36.0 in the Westman region. The Manitoba age-specific rates of hospitalization for males in the 35-54 and 55-64 age groups were about three times the female rates for the same age groups. One quarter of AMI hospitalized victims died in hospital. The Manitoba age-specific death rates for males in the 35-54, 55-64 and 65-74 age groups were double the rates for females in the same age groups. Of the 8,436 AMI victims under study, 86.4% had at least one other concurrent medical condition such as angina, other forms of ischemic heart disease, diabetes, or hypertension. Of AMI victims, 93.8% underwent at least one of the following procedures: coronary artery bypass surgery, angiogram, electrocardiogram, cardiac catheterization, arteriography, or blood cholesterol testing. A higher percentage of procedures was performed on males than on females.