Research Article: Validity of a minimally invasive autopsy for cause of death determination in maternal deaths in Mozambique: An observational study

Date Published: November 8, 2017

Publisher: Public Library of Science

Author(s): Paola Castillo, Juan Carlos Hurtado, Miguel J. Martínez, Dercio Jordao, Lucilia Lovane, Mamudo R. Ismail, Carla Carrilho, Cesaltina Lorenzoni, Fabiola Fernandes, Sibone Mocumbi, Zara Onila Jaze, Flora Mabota, Anelsio Cossa, Inacio Mandomando, Pau Cisteró, Alfredo Mayor, Mireia Navarro, Isaac Casas, Jordi Vila, Maria Maixenchs, Khátia Munguambe, Ariadna Sanz, Llorenç Quintó, Eusebio Macete, Pedro Alonso, Quique Bassat, Jaume Ordi, Clara Menéndez, Peter Byass

Abstract: BackgroundDespite global health efforts to reduce maternal mortality, rates continue to be unacceptably high in large parts of the world. Feasible, acceptable, and accurate postmortem sampling methods could provide the necessary evidence to improve the understanding of the real causes of maternal mortality, guiding the design of interventions to reduce this burden.Methods and findingsThe validity of a minimally invasive autopsy (MIA) method in determining the cause of death was assessed in an observational study in 57 maternal deaths by comparing the results of the MIA with those of the gold standard (complete diagnostic autopsy [CDA], which includes any available clinical information). Concordance between the MIA and the gold standard diagnostic categories was assessed by the kappa statistic, and the sensitivity, specificity, positive and negative predictive values and their 95% confidence intervals (95% CI) to identify the categories of diagnoses were estimated. The main limitation of the study is that both the MIA and the CDA include some degree of subjective interpretation in the attribution of cause of death.A cause of death was identified in the CDA in 98% (56/57) of cases, with indirect obstetric conditions accounting for 32 (56%) deaths and direct obstetric complications for 24 (42%) deaths. Nonobstetric infectious diseases (22/32, 69%) and obstetric hemorrhage (13/24, 54%) were the most common causes of death among indirect and direct obstetric conditions, respectively. Thirty-six (63%) women were HIV positive, and HIV-related conditions accounted for 16 (28%) of all deaths. Cerebral malaria caused 4 (7%) deaths. The MIA identified a cause of death in 86% of women. The overall concordance of the MIA with the CDA was moderate (kappa = 0.48, 95% CI: 0.31–0.66). Both methods agreed in 68% of the diagnostic categories and the agreement was higher for indirect (91%) than for direct obstetric causes (38%). All HIV infections and cerebral malaria cases were identified in the MIA. The main limitation of the technique is its relatively low performance for identifying obstetric causes of death in the absence of clinical information.ConclusionsThe MIA procedure could be a valuable tool to determine the causes of maternal death, especially for indirect obstetric conditions, most of which are infectious diseases.The information provided by the MIA could help to prioritize interventions to reduce maternal mortality and to monitor progress towards achieving global health targets.

Partial Text: As the Millennium Development Goals came to a close in 2015, the maternal mortality ratio (MMR) had dropped by 43% since 1990 [1]. Although this progress is certainly encouraging, it is lower than the 75% target initially planned, and hundreds of women still die every day due to complications of pregnancy or childbirth. In 2015, the number of estimated maternal deaths occurring worldwide was 303,000, most of which were preventable and disproportionately took place in low- and middle-income countries. The MMR in low-income countries in 2015 was 239 per 100,000 live births versus 12 per 100,000 live births in high-income countries, according to WHO [2]. In Mozambique, in 2015, the MMR was 489 per 100,000 live births, with an annual rate of reduction of 4.4% from 2005–2015 [3]. The aim of Sustainable Development Goal 3.1 is to reduce the global MMR to less than 70 per 100,000 live births by 2030 [4]. The accomplishment of this objective requires robust data sources to develop accurate estimates and, importantly, a thorough understanding of the causes of these deaths. Monitoring progress towards the 5th Millennium Development Goal, focusing on maternal health, revealed the lack of high-quality data in most countries, especially those with the highest MMR [1].

Coupled MIA and CDA procedures were performed in 57 women. Median age was 27 years (range 15–39 years). Thirty-one women (54%) died in the puerperal period, 9 (16%) died after an abortion, and 16 (28%) were pregnant at the time of death. In all 16 cases, the fetus and the placenta were in situ. Nevertheless, no autopsy was performed on these in situ fetuses because it was not considered as relevant to determine the cause of death. The placenta was analyzed as part of the CDA in 8 of these cases but was not contributory to the final diagnosis. Forty-four lived in the Maputo urban area, whereas 13 were transferred from a rural district.

This validation study shows, for the first time to our knowledge, that the MIA, a simplified postmortem procedure, can provide an acceptable correlation with the gold standard CDA diagnosis in maternal deaths. In this group, the agreement of the technique was 68% (kappa statistic: 0.48, 95% CI 0.31–0.66), a percentage of agreement similar to those observed in other age groups [16,17]. These findings suggest that this new method could provide reliable and relevant data regarding the causes of mortality associated with pregnancy and childbirth, particularly for indirect obstetric deaths, and thus contribute to reducing maternal mortality in the settings where this burden is highest.



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