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Quarterly Digest |
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| R.J. Danderfer | Soo-Hong Uh |
| Director | Manager |
| British Columbia | Information and Resource |
| Vital Statistics Agency | Management Branch |
| Vital Statistics Agency |

| 01 East Kootenay LHA 01 Fernie 02 Cranbrook 03 Kimberley 04 Windermere 05 Creston 18 Golden
02 West Kootenay-Boundary
03 North Okanagan
04 South Okanagan-Similkameen
05 Thompson
06 Fraser Valley |
07 South Fraser Valley LHA 35 Langley 36 Surrey 37 Delta
08 Simon Fraser
09 Coast Garibaldi
10 Central Vancouver Island
11 Upper Island/Central Coast
12 Cariboo
13 North West |
14 Peace Liard LHA 59 Peace River South 60 Peace River North 81 Fort Nelson
15 Northern Interior
16 Vancouver
17 Burnaby
18 North Shore
19 Richmond
20 Capital |
The Health Status Registry (HSR) is a comprehensive database of information on individuals with congenital anomalies, genetic conditions, and selected disabilities operated by the British Columbia Vital Statistics Agency under Section 10 of the Health Act. The Agency recently released the Health Status Registry Report: Congenital Anomalies, Genetic Defects, Selected Disabilities, British Columbia to 1998. This article describes some of the uses of the database and presents a sample of tables and figures from the report to demonstrate the information that the HSR can provide.
The Health Status Registry has collected information on birth defects and selected disabilities for nearly half a century. A person of any age living in British Columbia who is diagnosed as having a genetic condition or congenital anomaly, even if that condition or anomaly is not disabling, meets the criteria for registration. In addition, any child (19 years of age or less) who is diagnosed as having a physical, mental or emotional problem which is likely to interfere substantially with education or employment, or to have other long-term disabling effects, also meets the criteria for registration.
Data from the Registry has been used for a variety of published and unpublished studies of congenital anomalies. There have been studies concerning risk factors, such as maternal/paternal age and Down's syndrome, epidemiological studies, such as the incidence of cryptorchidism among siblings, studies concerning prevalence, such as cleft palate in the Aboriginal population, and studies concerning the life expectancy/causes of death of disabled people. HSR data could also be used to determine etiologies of anomalies in order to develop preventive measures or to measure the impact/effectiveness of immunization or other specific procedures or treatments.
An extremely important use of this database is birth defects monitoring. A birth defects monitor should serve as an "early warning system" to quickly alert medical health officers and epidemiologists of any changes in congenital anomaly rates. When congenital anomaly rate increases are seen, investigations can confirm the diagnoses of all possible and probable conditions, and then determine if any actions could reduce congenital anomaly risks. These risks could be the result of maternal infections, such as rubella, maternal use of prescription drugs (such as certain anti-convulsans or thalidomide), alcohol, exposure to radiation, or other environmental factors, such as soil or water contamination. Regional health authorities and medical health officers are increasingly interested in information on the occurance of congenital anomalies in their regions.
The Health Status Registry is a great deal more than a birth defects monitor. Although some congenital anomalies, such as limb reduction deformities, are obvious at birth, others may not be diagnosed until much later. For example, pyloric stenosis would typically be diagnosed several days to a few weeks after birth, minor heart defects might not be diagnosed for a few months, and some metabolism disorders will not manifest for several years. As a general rule, only half of congenital anomalies are reported at birth. The extended reporting time for a registry such as the HSR makes it more complete than a database designed only for birth defects monitoring. The HSR is one of the few registries of its type, with the potential to establish prevalence and incidence baselines for the province over a long time period, and to identify significant temporal or spatial variations.
HSR data has also been used by medical researchers, service organizations, public health nurses and medical health officers, government agencies, and the public. Uses of the data have included comparing the number of the HSR registered cases with actual caseloads in a particular area or with lists of clients served by an organization. The data can also be used to estimate the need for various types of health services or programs, although this kind of use has not been common. Consistent monitoring of the changing needs of the population with registrable disabilities may also help to indicate the number of individuals that could benefit from related program areas outside of the traditional health-care field, such as financial assistance, housing, independent living, and life-skill and vocation training. Both the Ministry of Education and the Ministry for Children and Families provide funding and/or services for "special needs" children, and the HSR represents an excellent potential data source for identifying and tracking these "special needs" children and forecasting their service needs.
HSR reporting sources represent the "data capture" points. Health Status Registry data have historically been collected from voluntary sources, although legislation now provides for mandatory reporting. The numbers and kinds of reporting sources have changed considerably over time. When the focus of the HSR changed to emphasize registering disabling or handicapping conditions only when they involved children, reports from many sources decreased and some sources for non-childhood conditions were discontinued. This has affected the extent of coverage of registrable cases, the degree of completeness of registrations, and the currency of data on individual cases. HSR case coverage varies by condition, with good ascertainment of some conditions, such as major anomalies that can be identifiable at birth, to very limited coverage for conditions that are difficult to diagnosis and/or manifest in childhood or later, such as fetal alcohol syndrome.
The utility of the HSR is dependent on comprehensive reporting. The concept of building case histories through data from multiple reporting sources over an extended period of time is an integral part of this kind of database. Reports on the same individual from several different sources serve to add and correct diagnostic information, thus improving its accuracy. Consistent and complete reporting from sources other than Vital Statistics is essential for good ascertainment of conditions that are not diagnosed at birth. Even if there are no changes in diagnostic information, reports on the same individuals over time are required to obtain updated address information. This follow-up is essential for accurate information pertaining to specific geographic areas.
Revitalization of the HSR has focussed on improved data quality and completeness. More than 35,000 diagnoses were registered by HSR reporting sources in 1997 and 1998. Data submitted on the hospital admission/discharge abstracts from acute care hospitals throughout the province via the Ministry of Health's Acute and Continuing Care Division (formerly known as Hospital Programs) has been a significant source of recent HSR data. During the fall of 1997, data from these hospitals covering the period 1993 through 1997 was obtained and added to the Registry. This information, plus data reported in 1998, resulted in more than 15,000 diagnoses.
More than 10,000 diagnoses were reported to HSR by British Columbia's Children's Hospital in 1997 and 1998, and Vital Statistics' Live Births, Stillbirths, and Deaths were the source of almost 5,000 diagnoses in this time period. Most health authorities in the health regions (formerly health units) were also reporting sources, providing nearly about 1,800 diagnoses. B.C. Children's Hospital Medical Genetics and Victoria General Hospital Medical Genetics also reported cases, providing more than 1,000 diagnoses in 1997 and 1998.
The HSR feature report provides additional information on reporting sources, as well as information on the HSR's history, mandate, policies and procedures. A dozen graphs, several maps, and more than 80 tables provide statistics on congenital anomalies, genetic conditions, and selected disabilities and handicapping conditions for the province as a whole and by health regions, and information on congenital anomalies by local health areas. A sample of these statistics follows.

Table 1 provides counts of congenital anomalies reported to the HSR by year of birth for 1989-1998. The reader is reminded that the numbers shown represent diagnoses reported to the Health Status Registry to year end 1998, not the number of cases actually occurring. The counts for total diagnoses include all congenital anomalies, whether major or minor. Congenital anomalies vary widely in their severity and in their impact on the future health of individuals afflicted. Some congenital anomalies require ongoing health care management or treatment, while others do not. Therefore, when assessing rates, consideration should be given to the types of anomalies that are contributing to the rates presented.
From 1989 to 1998, 18,000 cases were born in the province with more than 27,000 congenital anomaly diagnoses. Between 1,850 and 4,000 congenital anomaly diagnoses were reported for each year, and 1,300 to 2,550 births (live births and stillbirths) were registered with at least one congenital anomaly.
The largest category of congenital anomaly diagnoses was musculoskeletal deformities; the second largest was anomalies of the heart. These diagnoses occurred in about one in 66 and one in 112 births respectively. Approximately one quarter of all the congenital anomaly diagnoses were musculoskeletal deformities; and the most common of these were congenital dislocated hip and foot deformities (varus, valgus, and clubfoot). Anomalies of the heart were responsible for roughly a seventh of the congenital anomaly diagnoses reported to HSR for 1989-1998 births.




Congenital anomaly data can be used to look at changes in birth incidence rates over time. The figures shown here present trends based on three-year moving averages using HSR data for 1980-1998 births. The yearly counts for some congenital anomalies are small, so just a few cases can have a large impact on the rates. In addition, unexplained clusters of cases have often been found when examining congenital anomaly rates over time. Thus there may be no cases for a number of years, followed by several cases in one year, and then few or no cases. Moving averages are used to lessen the impact of these kinds of yearly fluctuations.
Figures 1 - 4 show trends in the rates for all congenital anomalies (total diagnoses), neural tube defects, cleft palate/lip, and Down's syndrome. All congenital anomalies (total diagnoses) and neural tube defects showed small decreases in the reported incidence rates for the time period 1980 to 1998, while cleft palate/lip and Down's syndrome showed an increase of less than one birth per 1,000 total births over the 1980 -1998 period. The birth incidence rate for all congenital anomalies (total diagnoses) for 1980-1998 averaged about one in every 16 births (live births plus stillbirths). The average rate for cleft palate/lip was about one in 420 births, Down's syndrome averaged one in 770 births, and neural tube defects had an incidence rate of less than one in 1,050 births.

The mother's usual residence at the time she gave birth can be used to present birth incidence information by geographic areas. Table 2 presents congenital anomaly cases by health region for 1989-1998, and indicates the regions where there was a statistically significant ratio between the observed and the expected cases. There were three regions that had statistically significant high ratios for reported cases with one or more congenital anomaly: 16 Vancouver, 08 Simon Fraser, and 15 Northern Interior. Eleven health regions had statistically significant low ratios for reported cases with congenital anomalies; the lowest of these were 01 East Kootenay, 14 Peace Liard, and 20 Capital.

Table 3 presents birth incidence rates for chromosomal anomalies by health region. Only health region 16 Vancouver showed a statistically significant high ratio. Health region 14 Peace Liard and 13 North West showed statistically significant low ratios.


Birth incidence information can also be produced for local health areas. Table 4 and Figure 5 show congenital anomaly cases by local health area for 1989-1998. There were 11 local health areas with statistically high ratios between observed and expected cases with congenital anomalies; the highest were 083 Central Coast, 163 Vancouver North East, 161 Vancouver City Centre, and 040 New Westminster. Twenty-three local health areas had statistically significantly fewer cases with congenital anomalies than expected; the lowest were 078 Enderby, 029 Lillooet, and 017 Princeton.

Table 5 shows chromosomal anomalies by local health area for 1989-1998. Five local health areas had statistically significant high ratios; the highest were 005 Creston, 045 West Vancouver-Bowen Island, and 163 Vancouver North East. Only 002 Cranbrook and 062 Sooke had statistically significant low ratios for chromosomal anomalies, and the ratio for Cranbrook was based on only 2 cases. There were also nine local health areas with no reported diagnoses of chromosomal anomalies.

There were nearly 4,000 B.C. residents registered with the HSR at year-end 1998 with one or more of the genetic conditions shown in Table 6. Hereditary hemolytic and aplastic anemias were reported to the HSR more frequently than any other genetic condition, and two thirds of the 500 individuals with these anemias were under the age of 25 years old. The next most frequently reported genetic conditions were cystic fibrosis (CF) and hemophilia/other coagulation defects, each accounting for slightly more than 400 people. Three quarters of the individuals with CF, and the majority of those with hemophilia and other coagulation defects, were under the age of 30.

Table 7 provides counts of children (less than 20 years of age) with one or more selected disabilities and handicapping conditions who were living in the province at year-end, 1998. Two thirds of the 10,572 children with disabilities were older than age nine, and the largest numbers were between 15 and 19 years of age. The small number of infants with disabilities reflects the tendency for many of these conditions not to be diagnosed until late in childhood.
The most frequent disabilities recorded were epilepsy (2,753 children registered), specific developmental delays (2,465), visual impairment/blindness (2,048), and mental retardation (1,537 children registered).
Several of these disabilities appear to be gender specific. About three-quarters of children with hyperkinetic syndrome and with osteochondropathies, and four fifths of Tourette's were boys, while three-quarters of those with curvature of the spine were girls.
Many additional tables, graphs, and maps can be found in the feature report Health Status Registry Report: Congenital Anomalies, Genetic Defects, Selected Disabilities, British Columbia to 1998, available on our web site at http://www.vs.gov.bc.ca/stats/hsr/index.html.
Alcohol-Related:
This category includes all deaths considered as being directly or indirectly related to alcohol as indicated by inclusion by the certifier of selected alcohol identifying conditions anywhere on the death record (including "lifestyle" field). It should be noted that where alcohol is an indirect cause of death (i.e. not UCOD) and the direct underlying cause of death falls within one of our selected causes (e.g. motor vehicle accidents), then this death may be counted in both columns. That is, not all of "alcohol-related" are exclusive. This category includes the ICD-10 codes: F100-F109, K700-K709, O993, P043, O354, Q860, G312, G621, G721, I426, K292, K860, X45, X65, Y14, T510-T512, T519. Note: now excludes acute pancreatitis, and cirrhosis not specifically identified as alcohol induced.
Assignment of Health Region:
Cases are assigned to Health Regions by the aggregation of appropriate LHAs.
Assignment of Local Health Area (LHA):
Allocation of LHA, in the case of births and deaths is based upon the usual residence (by postal code) of the mother and deceased respectively. Marriages are assigned to LHAs according to the place of the event. Community name is used in the absence of postal code.
Elderly Gravida:
Any mother who was 35 years of age or older at the time of delivery of a live born infant.
External Causes of Death:
Deaths due to environmental events, circumstances and conditions as the cause of injury, poisoning, and other adverse effects. Broad categories include accidents, suicide, medical or abnormal reactions (considered accidents), homicide, legal intervention, misadventures (counted as accident) and injury from war operations. Standard "Quarterly" tables under this heading include deaths due to accidents, suicide, homicide, and other. Accidents are subdivided by the following categories; motor vehicle accidents (MVA) (ICD-10 V020-V049, V090-V092, V093, V120-V149, V190-V196, V200-V249, V260-V349, V360-V449, V460-V549, V560-V649, V660-V749, V760-V799, V803-V805, V820-V821, V823-V839, V840-V875, V877-V8999, Y850), poisoning (X40-X49), falls (W00-W19), burns/fire (X00-X19), drowning (V900-V909, V920-V929, W65-W74), other accidents (V010-V019, V050-V069, V091, V099, V100-V119, V150-V189, V198-V199, V250-V259, V350-V359, V450-V459, V550-V559, V650-V659, V750-V759, V800-V802, V806-V819, V822, V876, V910-V919, V930-V949, V950-V978, V98-V99, W20-W64, W75-W99, X20-X39, X50-X59, Y40-Y849, Y859, Y86, Y880-Y883). Suicide ICD-10 codes are X60-X84, Y870; homicide (X85-Y09, Y871); "other [external]" consists of events of undetermined intent, legal interventions, and operations of war (Y10-Y369, Y890-Y899).
Note: the late effects of accidental poisoning, falls, and burns/fire are no longer identified separately for inclusion in these categories and are now part of "other accidents"). Trains are now considered motor vehicles in ICD-10 but for consistency, have been excluded from MVA counts to still be considered as "other transport".
Heart Disease:
Tables under this heading include deaths due to:
ICD-9:
The ninth revision of International Classification of Diseases, World Health Organization, Geneva, 1977. An internationally used system of approximately 12,000 four (and some three) digit numbers representing a system of categories to which morbid entities are assigned according to an established criteria. ICD provides a common basis of disease and injury classification that facilitates storage, retrieval, and tabulation of statistical data.
ICD-10:
The tenth revision of International Classification of Diseases and Related Health Problems, World Health Organization, 1992. In use beginning with year 2000, update of ICD-9 revised with alpha-numeric system and increased code detail (approximately 18,000). The BC Vital Statistics Agency and all their provincial counterparts utilize an ICD-10 that has been modified by the National Center for Health Statistics (NCHS) for use in the classification and analysis of medical mortality data in the United States (October, 1998).
Infant Deaths:
Deaths of children under one year of age.
Live birth:
The complete expulsion or extraction from its mother, irrespective of the duration of the pregnancy, of a product of conception in which, after the expulsion or extraction, there is:
Low Birth Weight:
Any live born infant weighing less than 2500 grams.
Neoplasms (ICD-10 C000-D489):
Although the vast majority of deaths in this category are due to malignant cancer, also included are benign, in-situ, and unspecified "tumours". Detailed ICD-10 breakdown used in "Neoplasm Deaths" tables are;
Other Selected Death Statistics:
Tables under this heading include deaths due to:
Premature/Pre-term:
Any live born infant less than 37 weeks gestation at delivery.
Respiratory Disease Death Statistics:
Tables under this heading include deaths due to the following:
Stillbirth:
The complete expulsion or extraction from its mother after at least twenty weeks of pregnancy or after attaining a weight of at least 500 grams, of a product of conception in which, after expulsion or extraction, there is no breathing, beating of the heart, pulsation of the umbilical cord or unmistakable movement of voluntary muscle.
Teenage Mother:
Any mother who was age 19 or less at the time of delivery.
UCOD:
Underlying cause of death - based upon application of standard international coding rules for determining sequential relationships of conditions and diseases from immediate cause backwards to underlying cause.
The editorial staff would like to invite any readers who wish to contribute an article or paper summary for publication in this Quarterly Digest to contact the Information and Resource Management Branch of the British Columbia Vital Statistics Agency. Articles should focus on health status issues in British Columbia. It is preferable that submissions be in "electronic media" format (e.g. Word, Word Perfect, Excel, Power Point, Corel, Pagemaker, etc.). Article presentation will be subject to space allowances and publishing deadlines.
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