Create a Table | About | Example | Definitions | Generate a Map | FAQ | Links
Cohort Data Related Definitions and Associated Formulas
ANIMATED FORMULAS
This link shows formulas used to calculate rates with examples.COHORT INDICATOR VARIABLE INFORMATION
This page list all variables available in the live birth/infant death cohort module.CALCULATE RELATIVE RISK PAGE
This page illustrates how to calculate the relative risk using the live birth/infant death cohort module.LIVE BIRTH: The complete expulsion or extraction from its mother of a product of human conception, irrespective of the duration of pregnancy, which, after such expulsion or extraction, breathes or shows any other evidence of life, such as beating of the heart, pulsation of the umbilical cord, or definite movement of voluntary muscles, whether or not the umbilical cord has been cut or the placenta is attached. (Definition recommended by World Health Organization in 1950). Heartbeats are to be distinguished from transient cardiac contractions; respirations are to be distinguished from fleeting respiratory efforts or gasps.
AGE OF CHILD AT DEATH
INFANT DEATH: Death of a live born infant under one year of age.
NEONATAL DEATH: Death of a live born infant under 28 days of age.
PERINATAL DEATH: Death occurring during the perinatal period (i.e. to 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 of a live born infant 28-364 days of age.
MARITAL STATUS ON BIRTH CERTIFICATE:
UNMARRIED - a birth which occurs to a woman who has never been married or who has been widowed or legally divorced from her husband in excess of 280 days.
MARRIED - a birth which occurs to a woman who has been married or was married within 280 days from conception.
RATES:
INFANT MORTALITY RATE: Infant deaths per 1,000 annual live births(see animated formulas).
CAUSE OF DEATH SPECIFIC RATE: Infant deaths due to a specific cause of death per 100,000 annual live births.
AGE SPECIFIC RATE: Age specific infant deaths over total number of annual live births per 1,000.
INDICATOR SPECIFIC RATE: Indicator specific infant deaths over indicator specific annual live births per 1,000.
95% CONFIDENCE INTERVALS CALCULATION:
r + 61.981*(r/n)1/2
Where r = infant mortality rate, n = number of live births (denominator), and 61.981=1.96*(1000)1/2
When frequencies are less than 100 then 95% confidence intervals are calculated using the formulas provided on pages 98-102 in the NCHS 2001 Birth Report a pdf document.RELATIVE RISK (RR) CALCULATION:
[a / (a + b)] / [c / (c + d)]
95% CONFIDENCE INTERVALS OF RELATIVE RISK CALCULATION:
Standard Error (SE) of the RR = square root( [b / {a*(a+b) } ] + [d / { c*(c+d) } ] )
95% Confidence Interval = RR * e(+1.96 * [SE RR] )
An example page of relative risk calculation with specific instructions and details is available by clicking here:(Cohort Relative Risk Calculation Page).MATERNAL RISK FACTORS
MOTHERS RECEIVED PRENATAL CARE IN THE 1ST TRIMESTER: Mothers received prenatal care in the 1st Trimester of pregnancy
MOTHERS DID NOT RECEIVE ANY PRENATAL CARE: Mother's received no prenatal care throughout pregnancy
MOTHER'S LESS THAN 18 Births where the age of the mother was less than eighteen.
EDUCATION LESS THAN HIGH SCHOOL: Mother received less than 12 years of education.
Return to the TopHOSPITAL LEVEL
LEVEL I
Level I hospitals provide services for uncomplicated deliveries and normal neonates. They must have the capability to manage normal pregnant women and uncomplicated labor and delivery of neonates who are at least 36 weeks of gestation with an anticipated birth weight of greater than 2000 grams. These hospitals must be able to manage an perinatal patient with acute or potentially life-threatening problems while preparing for immediate transfer to a higher level hospital.Level I hospitals as of October, 2003:
Abbeville County Memorial Hospital
Allen Bennett Memorial Hospital
Allendale County Hospital
Bamberg County Memorial Hospital
Carolinas Hospital System - Kingstree
Chester County Hospital
Chesterfield General Hospital
Clarendon Memorial Hospital
Colleton Medical Center
Hilton Head Regional Medical Center
Kershaw County Medical Center
Laurens County Hospital
Loris Community Hospital
Marlboro Park Hospital
Newberry County Memorial Hospital
Oconee Memorial Hospital
Providence Hospital Northeast
Saint Eugene Medical Center
Summerville Medical Center
Upstate Carolina Medical Center
W.J. Barge Memorial Hospital
Wallace Thomson Hospital.LEVEL II
Level II hospitals provide services for both the normal and selected high-risk obstetrical and neonatal patients. This level of care includes the management of neonates who are at least 32 weeks of gestation with an anticipated birth weight of at least 1500 grams. Neonates must be without acute distress or complex management requirements and must not be in need of ventilatory support for more than six cumulative hours nor require high frequency ventilation support. These hospitals manage no les than an average of 500 deliveries annually, calculated over the previous three years.Level II hospitals as of October, 2003:
Aiken Regional Medical Center
Anderson Area Medical Centers
Beaufort Memorial Hospital
Bon Secours-Saint Francis Xavier Hospital
Conway Hospital
East Cooper Regional Medical Center
Georgetown County Memorial Hospital
Grand Stand Regional Medical Center
Lexington Medical Center
Marion County Medical Center
Mary Black Memorial Hospital
Palmetto Baptist Medical Center -Easley
Regional Medical Center of Orangeburg/Calhoun Counties
Roper Hospital
Saint Francis Women's And Family Hospital
Springs Memorial Hospital
Trident Regional Medical Center
Tuomey Regional Medical Center
Women's Center Of Carolinas Hospital System
Carolina Pines Regional Medical CenterLEVEL IIE+
In addition of Level II requirements, Level IIE+ hospitals provide services for both normal and selected high-risk obstetrical and neonatal patients. This level of neonatal care includes the management of neonates who are at least 30 weeks of gestation with an anticipated birth weight of at least 1250 grams, as determined by estimations based upon best professional judgment, ultrasound, and /or available medical technology and instruments. Neonates are not in need of ventilatory support for more than 24 cumulative hours and do not require high-frequency ventilation support. These hospitals manage no less than an average of 1200 deliveries annually, calculated over the previous three years.Level IIE hospitals as of October 2003:
Piedmont Medical CenterLEVEL III HOSPITAL
Level III hospitals provides all aspects of perinatal care, including intensive care and a range of continuously available, sub-specialty consultation as recommended in the fourth edition of the Guidelines for Perinatal Care by the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. In addition to the Level II and IIE capabilities, Level III hospitals have the staffing and technical capability to manage high-risk obstetric and complex neonatal patients, including neonates requiring prolonged ventilatory support, surgical intervention, or 24-hour availability of multispecialty management. Level III hospitals must have no less than an average of 1500 deliveries annually, calculated over the previous three years, or at least 125 neonate admissions who weigh less than 1500 grams each, require ventilatory support, or require surgery.Level III hospitals as of October 2003:
Palmetto Health Baptist
Self Regional HealthcareREGIONAL PERINATAL CENTER
In addition to the Level III requirements for management of high-risk obstetric and complex neonatal conditions, Regional Perinatal Center hospitals provide consultative, outreach and support services to Level I, II, IIE and III hospitals in their region. These hospitals manage no less than an average of 2000 deliveries annually, calculated over the previous three years, or at least an average of 250 neonate admissions who weigh less than 1500 grams each, require ventilatory support, or require surgery. These hospitals must participate in residency programs for obstetrics, pediatrics and/or family practice. Continuing education and outreach education programs must be available to all referring hospitals, and physician-to-physician consultation must be available 24 hours a days. Regional Perinatal Centers must provide a perinatal transport system that operates 24 hours a day, seven days a week.Regional Perinatal Centers as of October 2003:
Greenville Memorial Medical Center
Palmetto Health Richland
McLeod Regional Medical Center
Medical University of South Carolina Medical Center
Spartanburg Regional Medical Center.RATE CALCULATIONS WITH SMALL NUMBERS:
There are variations in all statistics that 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 or births 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.BIRTHWEIGHT: VERY LOW BIRTHWEIGHT: Very low birthweight is a weight at birth which is less than 1,500 grams (3 pounds, 4 ounces), regardless of the period of gestation.
LOW BIRTHWEIGHT: Low birthweight is a weight at birth which is less than 2,500 grams (5 pounds, 8 ounces), regardless of the period of gestation.
NORMAL BIRTHWEIGHT: Normal birthweight is a weight at birth which is greater than 2,500 grams (5 pounds, 8 ounces), regardless of the period of gestation.
GRAMS WEIGHT CONVERSION CHART
500 grams or less = 1lb. 1 oz. or less
Return to the Top
501 - 1,000 grams = 1 lb. 2 oz. - 2 lb. 3 oz.
1,001 - 1,500 grams = 2 lb. 4 oz. - 3 lb. 4 oz.
1,501 - 2,000 grams = 3 lb. 5 oz. - 4 lb. 6 oz.
2,001 - 2,500 grams = 4 lb. 7 oz. - 5 lb. 8 oz.
2,501 - 3,000 grams = 5 lb. 9 oz. - 6 lb. 9 oz.
3,000 - 3,500 grams = 6 lb. 10 oz. - 7 lb. 11 oz.
3,501 - 4,000 grams = 7 lb. 12 oz. - 8 lb. 13 oz.
4,001 - 4,500 grams = 8 lb. 14 oz. - 9 lb. 14 oz.
4,501 - 5,000 grams = 9 lb. 15 oz. - 11 lb. 0 oz.
5,001 grams or more = 11 lb. 1 oz - or moreADEQUACY OF PRENATAL CARE: KESSNER INDEX:
ADEQUATE*
Gestation (weeks)**** Number of Prenatal Visits
13 or less 1 or more or not stated
14-17 2 or more
18-21 3 or more
22-25 4 or more
26-29 5 or more
30-31 6 or more
32-33 7 or more
34-35 8 or more
36 or more 9 or moreINADEQUATE**
Gestation (weeks)**** Number of Prenatal Visits
14-21*** 0 or not stated
22-29 1 or less or not stated
30-31 2 or less or not stated
32-33 3 or less or not stated
34 or more 4 or less or not statedINTERMEDIATE: All combinations other than specified above
* In addition to the specified number of visits indicated for adequate care, the Interval to the first prenatal visit has to be 13 weeks or less (first trimester).
** In addition to the specified number of visits indicated for inadequate care, all Women who started their prenatal care during the third trimester (28 weeks or later) are considered inadequate.
*** For this gestation group, care is considered inadequate if the time of the first visit is not stated.
**** When month and year are specified but day is missing, input 15 for day. Adequacy categories are in accord with recommendations of American College of Obstetrics and Gynecology and the World Health Organization.ADEQUACY OF PRENATAL CARE: KOTELCHUCK INDEX:
The Kotelchuck Index, also called the Adequacy of Prenatal Care Utilization (APNCU) Index, uses two crucial elements obtained from birth certificate data-when prenatal care began (initiation) and the number of prenatal visits from when prenatal care began until delivery (received services). The Kotelchuck index classifies the adequacy of initiation as follows: pregnancy months 1 and 2, months 3 and 4, months 5 and 6, and months 7 to 9, with the underlying assumption that the earlier prenatal care begins the better. To classify the adequacy of received services, the number of prenatal visits is compared to the expected number of visits for the period between when care began and the delivery date. The expected number of visits is based on the American College of Obstetricians and Gynecologists prenatal care standards for uncomplicated pregnancies and is adjusted for the gestational age when care began and for the gestational age at delivery.
A ratio of observed to expected visits is calculated and grouped into four categories-Inadequate (received less than 50% of expected visits), Intermediate (50%-79%), Adequate (80%-109%), and Adequate Plus (110% or more). The final Kotelchuck index measure combines these two dimensions into a single summary score. The profiles define adequate prenatal care as a score of 80% or greater on the Kotelchuck Index, or the sum of the Adequate and Adequate Plus categories.
The Kotelchuck Index does not measure the quality of prenatal care. It also depends on the accuracy of the patient or health care provider's recall of the timing of the first visit and the number of subsequent visits. The Kotelchuck Index uses recommendations for low-risk pregnancies, and may not measure the adequacy of care for high-risk women. The Kotelchuck Index is preferable to other indices because it includes a category for women who receive more than the recommended amount of care (adequate plus, or intensive utilization).
RACE:
Information on race of the mother and father is reported on birth and fetal death certificates, and the race of the decedent is reported on death certificates. Fetal deaths are reported by race of mother. As of 1990, Live Births are reported by race of mother instead of race of child. This change allows South Carolina's birth data to be consistent with the National Center for Health Statistics and other states throughout the United States. Race is reported as White, Black Other, and Unknown.ETHNICITY:
Ethnicity is reported independently of race on the birth certificate. Hispanic refers to those people whose origins are from Spain, Mexico or the Spanish-speaking countries of Central and South America. Tabulation categories are Hispanic, non-Hispanic, and unknown. If data is missing it is then assigned to the unknown category.RESIDENCE DATA:
Data allocated to the place in South Carolina where the person normally resided, regardless of where the event occurred.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 from 1949-1957; the Seventh Revision for 1958-1968; the Eighth 1969-1978; and the Ninth Revision went 1979-1998;and the Tenth Revision went into effect in 1999.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. However, the Tenth Revision introduced some of the most dramatic changes so far.
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. Taking the number of deaths classified to a given cause by the Tenth Revision and dividing the result by the number of deaths classified to that cause by the Eighth Revision derived the comparability ratios used with the Tenth Revision. Provisional comparability ratios for the United States as a whole, based on the Ninth and Tenth Revisions, have been developed for a limited number of causes published by the National Center for Health Statistics.
Return to the TopIMPLEMENTATION OF THE INTERNATIONAL CLASSIFICATION OF DISEASES (ICD )10TH REVISION
The ICD is a classification system developed collaboratively between the World Health Organization (WHO) and 10 international centers so that the medical terms reported by physicians, medical examiners, and coroners on death certificates can be grouped together for statistical purposes. ICD-10 replaces the ICD-9, used with 1979-1998 data.The purpose of the ICD and of WHO sponsorship is to promote international comparability in the collection, classification, processing and presentation of mortality statistics. New revisions of the ICD are implemented periodically so that the classification reflects advances in medical science.
ICD-10 affects the classification, processing, and presentation of mortality data. Some titles have changed. The total number of categories has doubled as a result of the addition or deletion of terms used to describe diseases or conditions. The transfer of certain diseases from one section to another reflects new discoveries and advances in knowledge on the nature or causes of particular diseases. The addition of separate categories identifies specific diseases or particular complications of diseases that are of growing interest. Additionally, the codes associated with each title have been converted from numeric to alphanumeric entities. The ICD rules for processing mortality data are generally similar but account for some changes observed in mortality statistics.
HOW ICD-10 COMPARES TO ICD-9
The intent of developing new revisions is to incorporate changes in medical knowledge. Compared with ICD-9, the ICD-10 has:
· expanded detail for many conditions (e.g., viral hepatitis has been expanded from ICD-9 code 070, a single 3-digit category, to ICD-10 codes B15-B19, five 3-digit categories)
· transferred conditions around the classification (e.g., hemorrhage has been moved from the circulatory chapter to the symptoms and signs chapter)
· used alphanumeric codes instead of numeric codes (e.g., code for diabetes mellitus was 250 in ICD-9 and is E10-E14 in ICD-10)
· modified coding rules (e.g., the "Old pneumonia, influenza, and maternal conditions" and "Error and accidents in medical care" coding rules have been eliminated)
· modified the tabulations lists (e.g., the US' ICD-10 113-cause list replaces the US' ICD-9 72-cause list)Assistance in using the ICD-10 can be obtained by contacting the National Center for Health Statistics, Data Dissemination Branch, 6525 Belcrest Road, Room 1064
Hyattsville, Maryland 20782-2003(301) 458-4636 (voice) (301) 458-4027 (fax)
For more information about the ICD-10:
Return to the Top
ICD-10 Web page at: www.cdc.gov/nchs/icd9.htm
Or see the National Center for Health Statistics(NCHS) Web site at:
www.cdc.gov/nchs/
SC Home | SC DHEC | PHSIS | SCAN | MICA | Contact Us