Comparability - In order that disease classifications
may be consistent with advances in medical science and changes in diagnostic practice,
any system for categorizing causes of death must periodically be revised. Major
revisions in the International Classification of Diseases (ICD) , by which
causes of death are classified, occur approximately every ten years, and each decennial
revision of the ICD has produced some break in comparability of cause of death statistics.
In South Carolina, the Sixth Revision of the ICD was used for 1949 -1957; the Seventh
Revision for 1958-1968; the Eighth Revision for 1969-1978; and the Ninth Revision
went into effect in 1979.
Prior to 1949, under the first five revisions, cause of death was selected on the
basis of priority tables for multiple causes, as set forth in The Manual For Joint
Causes of Death. Under the Sixth, Seventh, Eighth, and Ninth Revisions of
the International Lists, the cause selected for tabulation has been the "underlying"
cause, defined as the "disease or injury which initiated the train of morbid events,
leading directly to death" (ICDA, Eighth Revision, 1968, Vol. 1, page xxix).
The introduction of the concept of "underlying" cause in 1949, with the Sixth Revision,
resulted in a basic change in classification of death which seriously affects the
interpretation of mortality trends before and after 1949. The Seventh Revision was
essentially a clarification of the Sixth Revision, but the Eighth Revision introduced
some major modifications in classification lists and coding procedures. The Ninth
Revision also brought some major changes in classification and coding.
In order to make valid comparisons of mortality by cause for events classified by
different revisions of the ICD, comparability ratios were developed. Comparability
ratios are computed by the National Center for Health Statistics from the results
of dual coding of certificates according to the old and the new procedures. The
comparability ratios used with the Ninth Revision were derived by taking the number
of deaths classified to a given cause by the Ninth Revision and dividing the result
by the number of deaths classified to that cause by the Eighth Revision. Provisional
comparability ratios for the United States as a whole, based on the Eighth and Ninth
Revisions, have been developed for a limited number of causes. These can be found
in the Monthly Vital Statistics Report, Vol. 28, Number 11 published by the
National Center for Health Statistics, February 29, 1980.
Fetal Death - Death prior to the complete expulsion
or extraction from its mother of a product of human conception, irrespective of
the duration of pregnancy; the death is indicated by the fact that after such expulsion
or extraction, the fetus does not breathe or show any other evidence of life, such
as beating of the heart, pulsation of the umbilical cord, or definite movement of
voluntary muscles (Definition recommended by World Health Organization in 1950).
A fetal death is required to be reported if the fetus has completed or passed the
twentieth week of gestation or weighs 350 grams or more (Weight criteria effective
in 1978). Vital Statistics Laws and Regulations 61-19: Vital Statistics,
Section 21(a). Heartbeats are to be distinguished from transient cardiac contractions;
respirations are to be distinguished from fleeting respiratory efforts or gasps.
Infant Death - Death of a live born infant under
one year of age.
Maternal Death - Death of a woman whose cause
of death is assigned to Complications of Pregnancy, Childbirth, and Puerperium(Ninth
Revision ICD 630-676). If death occurred more than 42 days after termination of
pregnancy, the death is not considered to be pregnancy-related and is not assigned
to codes 630-676.
Medical Certification of Death - The medical
certification of death can be made only by a person authorized by law, usually a
physician or a coroner. Thus, the reliability and accuracy of cause-of-death statistics
are, to a large extent, governed by the acumen and ability of the doctor or coroner
to make the proper diagnosis and by the care with which the death certificate is
completed. It is recognized that death may not result from a single morbid condition.
Since 1980, South Carolina medical certifiers have been asked to provide contributing
conditions adding to the underlying cause of death information.
Multiple Cause of Death - Cause of death statistics
have, for many years, been based only on the underlying cause of death, the single
disease or injury that initiated the sequence of events leading to death or the
circumstances of the accident that produced the fatal injury. The underlying cause
is selected by a computerized algorithm called the Automated Classification of Medical
Entities (ACME) from the ordering of conditions reported by physicians or coroners
on the death certificate. Analysis of the underlying cause of death information
allows for simplified, consistent reporting of data and provides a means of evaluating
the impact of public health initiatives. When more than one cause is reported on
the certificate, however, the tabulation of only one cause for mortality statistics
may lead to a loss of information on any condition that is an element in the death
but that is not selected as the underlying cause of death. Cause-of-death statistics
are usually based on the underlying cause of death, a single disease or injury circumstance
that initiated the sequence of events leading to death. In this system, each death
is assigned one underlying cause of death. However, death certificates provide for
the inclusion of more information than the underlying cause of death alone. The
immediate cause of death, antecedent causes giving rise to the immediate cause,
and other significant conditions contributing to the death also may be entered by
the medical certifier. These data provide a way of estimating the impact of significant
co-factors contributing to a death and offer a means of utilizing information on
causes, such as hypertension, asthma, bronchitis, and diabetes, that are frequently
present at death but that are usually not lethal by themselves. Each death is assigned
one underlying cause and up to nineteen contributing causes of death.
Neonatal Death - Death occurring during the neonatal
period (i.e. under 28 days of age).
Occurrence Data - Data allocated to the place in
South Carolina where the event occurred, regardless of the usual residence of the
Perinatal Death - Death occuring during the perinatal
period (i.e. a live born infant less than 28 days of age and a fetus that has passed
the twentieth week of gestation or weighs 350 grams or more).
Postneonatal Death - Death occurring during the
postneonatal period (i.e. 28-364 days of age).
Race - Race of the decedent is reported on death certificates.
Fetal deaths are reported by race of mother.
Rate Calculations with Small Numbers - There are
variations in all statistics which are the result of chance. This characteristic
is of particular importance in classifications with small numbers of events where
small variations are proportionately large in relation to the base figure. As an
example, small changes in the number of deaths in small population areas or in the
number of deaths from uncommon causes could result in large changes in these crude
rates. For this reason, rates for counties with small populations or other small
bases should be used cautiously. In these tables, rates are not calculated for places
of less than 2500 population or when the number of events is less than 5 for a particular
category, due to the known instability of rates based on small numbers.
Residence Data - Data allocated to the place in South
Carolina where the person normally resided, regardless of where the event occurred.
Underlying Cause of Death - Disease or injury that
initiated the sequence of morbid events leading directly to death. (International
Classification of Disease)
Population Data: Population Data for years 1990-2000 are provided by South Carolina Office of Research and Statistics
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