Revealing the burden of maternal mortality: a probabilistic model for determining pregnancy-related causes of death from verbal autopsies
Tóm tắt
Substantial reductions in maternal mortality are called for in Millennium Development Goal 5 (MDG-5), thus assuming that maternal mortality is measurable. A key difficulty is attributing causes of death for the many women who die unaided in developing countries. Verbal autopsy (VA) can elicit circumstances of death, but data need to be interpreted reliably and consistently to serve as global indicators. Recent developments in probabilistic modelling of VA interpretation are adapted and assessed here for the specific circumstances of pregnancy-related death. A preliminary version of the InterVA-M probabilistic VA interpretation model was developed and refined with adult female VA data from several sources, and then assessed against 258 additional VA interviews from Burkina Faso. Likely causes of death produced by the model were compared with causes previously determined by local physicians. Distinction was made between free-text and closed-question data in the VA interviews, to assess the added value of free-text material on the model's output. Following rationalisation between the model and physician interpretations, cause-specific mortality fractions were broadly similar. Case-by-case agreement between the model and any of the reviewing physicians reached approximately 60%, rising to approximately 80% when cases with a discrepancy were reviewed by an additional physician. Cardiovascular disease and malaria showed the largest differences between the methods, and the attribution of infections related to pregnancy also varied. The model estimated 30% of deaths to be pregnancy-related, of which half were due to direct causes. Data derived from free-text made no appreciable difference. InterVA-M represents a potentially valuable new tool for measuring maternal mortality in an efficient, consistent and standardised way. Further development, refinement and validation are planned. It could become a routine tool in research and service settings where levels and changes in pregnancy-related deaths need to be measured, for example in assessing progress towards MDG-5.
Tài liệu tham khảo
Abou-Zahr C: Maternal Mortality Overview. In Health Dimensions of Sex and Reproduction Global Burden of Disease and Injury Series Vol III. Edited by: Murray CJL and Lopez AD. Geneva, World Health Organisation; 1998:111-164.
Graham WJ: Now or never: the case for measuring maternal mortality. Lancet 2002, 359: 701-704. 10.1016/S0140-6736(02)07817-0
Byass P: Person, place and time- but who, where, and when? Scandinavian Journal of Public Health 2001, 29: 84-86. 10.1080/14034940152393336
Chandramohan D, Rodrigues LC, Maude GH, Hayes RJ: The validity of verbal autopsies for assessing the causes of institutional maternal death. Studies in Family Planning 1998, 29: 414-422. 10.2307/172253
Ronsmans C, Vanneste AM, Chakraborty J, Van Ginneken J: A comparison of three verbal autopsy methods to ascertain levels and causes of maternal deaths in Matlab, Bangladesh. International Journal of Epidemiology 1998, 27: 660-666. 10.1093/ije/27.4.660
WHO: Beyond the Numbers: Reviewing maternal deaths and complications to make pregnancy safer. Geneva, ; 2004.
Kahn K, Tollman SM, Garenne M, Gear JSS: Validation and application of verbal autopsies in a rural area of South Africa. Tropical Medicine and International Health 2000, 5: 824-831. 10.1046/j.1365-3156.2000.00638.x
Anker M: The effect of misclassification error on reported cause-specific mortality fractions from verbal autopsy. International Journal of Epidemiology 1997, 26: 1090-1096. 10.1093/ije/26.5.1090
Todd JE, De Francisco A, O'Dempsey TJ, Greenwood BM: The limitations of verbal autopsy in a malaria-endemic region. Annals of Tropical Paediatrics 1994, 14: 31-36.
Hill K, El-Arifeen S, Koenig M, Al-Sabir A, Jamil K, Raggers H: How should we measure maternal mortality in the developing world? A comparison of household deaths and sibling history approaches. Bulletin of the World Health Organisation 2006, 84: 173-180. 10.2471/BLT.05.027714
InterVA: [www.interva.net].
Fantahun M, Fottrell E, Berhane Y, Wall S, Högberg U, Byass P: Assessing a new approach to verbal autopsy interpretation in a rural Ethiopian community: the InterVA model. Bulletin of the World Health Organisation 2006, 84: 204-210. 10.2471/BLT.05.028712
Byass P, Fottrell E, Huong DL, Berhane Y, Corrah PT, Kahn K, Muhe L, Van DD: Refining a probabilistic model for interpreting verbal autopsy data. Scandinavian Journal of Public Health 2006, 34: 26-31. 10.1080/14034940510032202
Byass P, Huong DL, Minh HV: A probabilistic approach to interpreting verbal autopsies: methodology and preliminary validation in Vietnam. Scandinavian Journal of Public Health 2003, 31: 32-37. 10.1080/14034950310015086
WHO, UNICEF, UNFPA: Estimates of maternal mortality. 2000.
Wurthwein R, Gbangou A, Sauerborn R, Schmidt CM: Measuring the local burden of disease: a study of life lost in rural Burkina Faso. International Journal of Epidemiology 2001, 30: 501-508. 10.1093/ije/30.3.501
Sankoh OA, Kynast-Wolf G, Kouyate B, Becher H: Patterns of adult and old-age mortality in rural Burkina Faso. Journal of Public Health Medicine 2003, 25: 372-376. 10.1093/pubmed/fdg080
INDEPTH: Founding Document (Available at: www.indepth-network.org). 1998.
Soleman N, Chandramohan D, Shibuya K: Verbal autopsy: current practices and challenges. Bulletin of the World Health Organisation 2006, 84: 239-245. 10.2471/BLT.05.027003
Quigley M, Chandramohan D, Setel P, Binka F: Validity of data-derived algorithms for ascertaining causes of adult death in two African sites using verbal autopsy. Tropical Medicine and International Health 2000, 5: 33-39. 10.1046/j.1365-3156.2000.00517.x
WHO: HIV/TB (Available at: http://www.who.int/tb/hiv). 2006.
WHO, UNICEF, UNFPA: Maternal mortality in 2000: estimates developed by WHO, UNICEF and UNFPA. Geneva, Department of Reproductive Health and Research, WHO; 2004.
Whitty CJM, Edmonds S, Mutabingwa TK: Malaria in Pregnancy. British Journal of Obstetrics and Gynaecology 2005, 112: 1189-1195.
WHO: The Africa Malaria Report. Geneva, ; 2003.
Chandramohan D, Setel P, Quigley M: Effect of misclassification of cause of death in verbal autopsy: can it be adjusted? International Journal of Epidemiology 2001, 30: 509-514. 10.1093/ije/30.3.509
Yang G, Rao C, Ma J, Wang L, Wan X, Dubrovsky G, Lopez AD: Validation of verbal autopsy procedures for adult deaths in China. International Journal of Epidemiology 2006, 35: 741-748. 10.1093/ije/dyi181
Chandramohan D, Maude GH, Rodrigues LC, Hayes RJ: Verbal autopsies for adult deaths: their development and validation in a multicentre study. Tropical Medicine and International Health 1998, 3: 436-446.
Setel P, Whiting DR, Hamed Y, Chandramohan D, Wolfson LJ, Alberti KGMM, Lopez AD: Validity of verbal autopsy procedures for determining cause of death in Tanzania. Tropical Medicine and International Health 2006, 11: 681-696. 10.1111/j.1365-3156.2006.01603.x
Marsh DR, Sadruddin S, Fikree FF, Krishman C, Darmstadt GL: Validation of verbal autopsy to determine the cause of 137 neonatal deaths in Karachi, Pakistan. Paediatric and Perinatal Epidemiology 2003, 19: 132-142. 10.1046/j.1365-3016.2003.00475.x
Freeman JV, Christian P, Khatry SK, Adhikari RK, LeClerq SC, Katz J, Darmstadt GL: Evaluation of neonatal verbal autopsy using physician review versus algorithm-based cause of death assignment in rural Nepal. Paediatric and Perinatal Epidemiology 2005, 19: 323-331. 10.1111/j.1365-3016.2005.00652.x
Gajalakshmi V, Peto R: Verbal autopsy procedure for adult deaths. International Journal of Epidemiology 2006, 35: 748-750. 10.1093/ije/dyl112
Garenne M, Fauveau V: Potential and limits of verbal autopsies. Bulletin of the World Health Organisation 2006, 84: 164. 10.2471/BLT.05.029124