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RESEARCH AND PRACTICE |
Daniel J. Pallin, Vandana Sundaram, Fabienne Laraque, and Louise Berenson are with the New York City Department of Health. At the time of the study, Daniel J. Pallin was also with the Preventive Medicine Residency Program, Brigham and Women’s Hospital, Boston, Mass. Vandana Sundaram and Fabienne Laraque are with the Health Information Services Unit, Maternal, Infant and Reproductive Health Program. Louise Berenson is with the Office of Vital Statistics. David R. Schomberg is with the Office of the Chief Medical Examiner, New York City.
Correspondence: Requests for reprints should be sent to Fabienne Laraque, MD, MPH, Office of Family Health, New York City Department of Health, 2 Lafayette St, 18th Floor, Box 34A, New York, NY 10007 (e-mail: flaraque{at}health.nyc.gov).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Objectives. This study examined the usefulness of computer-assisted active surveillance in identifying maternal deaths in New York City.
Methods. Computerized searches of hospital discharge and autopsy record databases were conducted for maternal deaths occurring in 1997.
Results. Active surveillance revealed 14 new maternal deaths not previously reported, an 88% increase. Nine of these deaths were found through the hospital discharge database search, 1 was found through the autopsy record search, and 4 were found in both searches. Overall maternal mortality ratios associated with active surveillance and routine surveillance were 24.3 and 13.0 deaths per 100 000 live births, respectively.
Conclusions. Active surveillance of maternal mortality is useful in identifying new maternal deaths. Existing databases can be used relatively easily to augment routine surveillance of maternal mortality.
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Vital record linkage, review of autopsy records, and searches of hospital discharge databases have been used to detect higher percentages of maternal deaths.3,5,6,11–13 Vital record linkage, which links birth or abortion files to women’s death files, has been automated on an experimental basis, allowing a system of active surveillance that is relatively easy to use and has high sensitivity and specificity.11 New York City and other reporting areas have sought to improve surveillance of maternal mortality by adding a check box to death certificates to indicate a recent pregnancy.3
Because many maternal deaths occur during hospital admissions, the availability of hospital discharge databases raises the possibility of computerized active surveillance of maternal mortality. Our goal was to test the usefulness of a hospital discharge database and an autopsy record search as methods of active surveillance of maternal mortality in New York City for 1997.
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METHODS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Data Sources and Case Selection
Routine surveillance.
The New York City health department routinely receives death certificates, either from the medical examiner or from reporting physicians, that are coded as "maternal" by nosologists. Codes are assigned according to the ICD-9 system and are based on the cause(s) listed. We reviewed all maternal deaths reported in 1997.17
Hospital discharge data. The Statewide Planning and Research Cooperative System (SPARCS) contains records for all hospital discharges occurring in New York State.18 We obtained a file of all SPARCS records pertaining to females aged 10 to 65 years who died in New York City hospitals in 1997. Each SPARCS record contained the disposition (i.e., discharged, transferred, deceased) and up to 31 diagnostic and procedure codes from ICD-9, as well as the medical record number, race/ethnicity, insurance status, and age of each patient.
To identify codes used in the hospital discharge database that might indicate pregnancy, we reviewed the ICD-9 and New York State diagnosis-related group (DRG) categories (the latter describe reasons for hospital admissions and the treatments received by patients). A physician (Daniel J. Pallin) with computer programming expertise spent approximately 300 hours studying the SPARCS system, reviewing the ICD-9 and DRG systems, and writing the programs to identify the deaths (using SAS, version 6.12). In addition to the ICD-9 codes that explicitly indicate maternal causes of death (630–676), we selected 152 other diagnostic and procedural codes that indicated pregnancy, including 792.3 (abnormal finding, amniotic fluid), V22 (normal pregnancy), and 69.01 (dilation and curettage for termination of pregnancy). Records bearing any of these codes were flagged via the search.
Autopsy record database. Narrative autopsy reports containing gross anatomic findings, microscopic examination results, and final causes of death are stored as text files by the Office of the Chief Medical Examiner. We used Microsoft Windows to search these files for all documents that contained any of the following words or word fragments: gesta-, preg-, amni-, abortion, ectopic, and placenta. This search required approximately 2 hours.
Medical records. We reviewed obstetric and other medical records for all cases flagged to confirm that these cases involved maternal deaths, to verify causes of death, and to collect data on characteristics such as race/ethnicity, insurance status, and age.
Data Analysis
Analyses were conducted with SAS. We noted the sensitivity and ease of use of each surveillance method and compared, according to method used, demographic data for cases found. Causes of maternal death were tabulated. These causes were determined via medical record review by a physician (Daniel J. Pallin) rather than through the ICD-9 codes noted on death certificates.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Of the 14 maternal deaths newly identified via active surveillance, 9 (64%) were found through the SPARCS hospital discharge database search alone, and 1 (7%) was found via the autopsy database search alone. The remaining 4 deaths were found with both search methods. All 16 routine surveillance deaths were found by at least 1 of the active surveillance methods; the SPARCS search found 13 (81%), and the autopsy database search found 12 (75%; Table 1
).
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The hospital discharge database search flagged 32 cases for 1997, of which 26 were confirmed as maternal deaths. Of the remaining 6 cases, 4 involved pregnant women who had not died; clerical error was possibly the reason they were listed as deceased. In addition, 2 deaths did not result from pregnancy complications. This led to a false-positive rate of 19% (6 of 32).
The autopsy database search flagged a total of 17 maternal deaths for 1997. Of these deaths, 2 were missed with routine surveillance owing to coding error, and 2 were missed because the contribution of pregnancy was not accurately noted on the death certificate.
Epidemiological Analysis
Table 2 displays selected characteristics of the 30 confirmed maternal deaths. There were no significant differences in any of these characteristics between the cases found by routine and those found by active surveillance.
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). Of the 30 maternal deaths, 7 resulted from medical intervention, and only 2 of these deaths were identified via routine surveillance. The other 5 deaths were the result of the following: probable adverse reaction to a medication, complications of elective anesthesia, complications of manual placental extraction, and cesarean delivery complications.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Our results allow certain conclusions to be drawn about the utility of computerized databases for active maternal mortality surveillance. Hospital discharge database searches detected 87% of the maternal deaths occurring in 1997. This rate compared favorably with routine surveillance, which detected only 53% of the deaths. Hospital discharge search was especially sensitive in the case of inpatient maternal deaths, detecting 96% of these deaths. The initial programming for this search involved a relatively substantial time allocation, but once the program is written and verified, this method can be used relatively easily in subsequent years to detect maternal deaths in areas that maintain hospital discharge databases.
The autopsy database search was performed with minimal effort and required a limited amount of time. This method complemented hospital discharge searches by identifying deaths that occurred outside hospitals.
The use of computerized databases permits flexibility in defining the target of surveillance. For example, in this study we could easily have broadened our definition to include all deaths occurring within a year of pregnancy, as advocated by CDC and the American College of Obstetrics and Gynecology.4 We also had the ability to include other causes of death that may be deemed maternal but that are not included in the maternal ICD-9 code range. Although the tenth revision of the ICD (ICD-10) accounts for pregnancy-related deaths that occur more than 42 days after pregnancy termination, active surveillance would still detect cases missed by routine surveillance.19
Our study also shows that verification of surveillance results via medical record review is important. Our review revealed a falsepositive rate of 19% for the hospital discharge search, as well as 1 false positive among the cases reported through routine surveillance.
An important limitation of this study was that we did not use vital records linkage, which has been demonstrated to be a successful method of increasing case ascertainment for maternal deaths.5,6,11 A study involving these 2 methods, vital records linkage and hospital discharge search, would be useful.
This study demonstrates not only that active surveillance increases case ascertainment but also that causes of death differ according to surveillance method. The finding that medical interventions were the second highest contributor to maternal deaths and were the most likely to be missed by routine surveillance highlights the importance of active maternal mortality surveillance.
In conclusion, routine surveillance of maternal mortality should be augmented by periodic or continuous active surveillance. Incorporation of computer-assisted active surveillance will improve case finding and, if desired, permit a broadening of the existing definition of maternal mortality. However, we urge that whenever MMRs are estimated through active surveillance methods, the reported ratio be labeled "active surveillance maternal mortality ratio" to avoid misinterpretation of the ratio as an increase in maternal mortality.
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Acknowledgments |
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Human Participant Protection
This study was approved by the New York Statewide Planning and Research Cooperative System Data Protection Review Board and by the New York City Department of Health Institutional Review Board.
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Footnotes |
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Accepted for publication August 29, 2001.
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References |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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2. Mertz KJ, Parker AL, Halpin GJ. Pregnancy-related mortality in New Jersey, 1975–1989. Am J Public Health. 1992;82:1085–1088.
3. Allen MH, Chavkin W, Marinoff J. Ascertainment of maternal deaths in New York City. Am J Public Health. 1991;81:380–382.
4. Atrash HK, Rowley D, Hogue CJ. Maternal and perinatal mortality. Curr Opin Obstet Gynecol. 1992;4:61–71.[Medline]
5. May WJ, Buescher PA. Enhanced maternal mortality surveillance in North Carolina, 1988 and 1989. MMWR Morb Mortal Wkly Rep. 1991;40:469–471.[Medline]
6. Floyd V, Hadley C, Lavoie M, et al. Pregnancyrelated mortality—Georgia, 1990–1992. MMWR Morb Mortal Wkly Rep. 1995;44:93–96.[Medline]
7. Starzyk P, Frost F, Kobayashi JM. Misclassification of maternal deaths—Washington State. MMWR Morb Mortal Wkly Rep. 1986;35:621–623.[Medline]
8. Benedetti TJ, Starzyk P, Frost F. Maternal deaths in Washington State. Obstet Gynecol. 1985;66:99–101.
9. Comas A, Navarro A, Conde J, et al. Misreporting of maternal mortality in Puerto Rico. Bol Asoc Med P R. 1990;82:343–346.[Medline]
10. Schuitemaker N, Van Roosmalen J, Dekker G, et al. Underreporting of maternal mortality in the Netherlands. Obstet Gynecol. 1997;90:78–82.[Abstract]
11. Jocums S, Mitchel EP Jr. Monitoring maternal mortality using vital records linkage. Am J Prev Med. 1995;11:75–78.[Medline]
12. Dye TD, Gordon H, Held B, et al. Retrospective maternal mortality case ascertainment in West Virginia, 1985 to 1989. Am J Obstet Gynecol. 1992;167:72–76.[Medline]
13. Nannini A, Weiss J, Kim J, et al. Enhanced maternal mortality surveillance in Massachusetts. In: Abstracts of the Maternal, Infant, and Child Health Epidemiology Workshop, December 1999, Atlanta, Ga.
14. Manual of the International Statistical Classification of Diseases, Injuries and Causes of Death, 9th Revision. Geneva, Switzerland: World Health Organization; 1977.
15. Scott JR, ed. Danforth’s Obstetrics and Gynecology. 7th ed. Philadelphia, Pa: Lippincott-Raven; 1994:1042.
16. DeVita VT. Cancer: Principles and Practice of Oncology. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:1501.
17. Office of Vital Statistics. Summary of Vital Statistics 1997, the City of New York. New York, NY: New York City Dept of Health; 1998.
18. Statewide Planning and Research Cooperative System (SPARCS). Albany, NY: New York State Dept of Health; 1999.
19. International Statistical Classification of Diseases and Related Health Problems, 10th Revision. Geneva, Switzerland: World Health Organization; 1992.
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| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
