Factors associated with physician agreement and coding choices of cause of death using verbal autopsies for 1130 maternal deaths in India

The reliability of maternal audit instruments to assign cause of death in maternal deaths review process: a systematic review and meta-analysis

BACKGROUND

Maternal Death Reviews (MDR) can assist in formulating prevention strategies to reduce maternal mortality. To support MDR, an adequate MDR instrument is required to accurately identify the underlying causes of maternal deaths. We conducted a systematic review and meta-analysis to determine the reliability of maternal death instruments for conducting the MDR process.

METHOD

Three databases: PubMed, ProQuest and EBSCO were systematically searched to identify related research articles published between January 2004 and July 2019. The review and meta-analysis involved identification of measurement tools to conduct MDR in all or part of maternal audit. Eligibiliy and quality of studies were evaluated using the Modified Quality Appraisal of Diagnostic Reliability (QAREL) Checklist: Reliability Studies.

RESULTS

Overall, 242 articles were identified. Six articles examining the instrument used for MDR in 4 countries (4 articles on verbal autopsy (VA) and 2 articles on facility-based MDR) were included. None of studies identified reliability in evaluation instruments assessing maternal audit cycle as a comprehensive approach. The pooled kappa for the MDR instruments was 0.72 (95%CI:0.43-0.99; p < 0.001) with considerable heterogeneity (I² = 96.19%; p < 0.001). Subgroup analysis of MDR instruments showed pooled kappa in VA of 0.89 (95%CI:0.52-1.25) and facility-based MDR of 0.48 (95%CI:0.15-0.82). Meta-regression analysis tended to show the high heterogeneity was likely associated with sample sizes, regions, and year of publications.

CONCLUSIONS

The MDR instruments appear feasible. Variation of the instruments suggest the need for judicious selection of MDR instruments by considering the study population and assessment during the target periods.

Determining the Cause of Death: Mortality Surveillance Using Verbal Autopsy in Indonesia

In the absence of a vital registration and health information systems, Indonesia does not have complete, accurate, and continuous data to summarize the mortality statistics of the population, nor determine the exact cause of death. Verbal autopsies performed in a community-based mortality surveillance have been used to provide information on the cause of deaths in such context. However, physician review of verbal autopsy can be expensive, time-consuming, and give inconsistent results, raising concern about its reliability. We used the Purworejo Health and Demographic Surveillance System's (HDSS) mortality data collected between 2000 and 2002 and assigned causes of death for all age groups using Interpreting Verbal Autopsy-4, analytic software that applies a probabilistic model. A total of 1,999 deaths were identified among 55,581 individuals surveyed in 14,409 households; 830 deaths were able to be recorded using the standardized World Health Organization (WHO) verbal autopsy questionnaire. We calculated the proportion of different causes of death and its incidence rate (IR) ratios with 95% confidence interval (CI) to compare the IR per person-years-observation (PYO). The IR of stroke was 126.7 per 100,000 PYO (95% CI: 109.7, 143.7); acute respiratory infection including pneumonia was 70.8 per 100,000 PYO (95% CI: 58.1, 83.5); and the IR of other and unspecified cardiac diseases was 57.7 per 100,000 PYO (95% CI: 46.2, 69.2). Stroke was indicated as the leading cause of death among elderly people aged 50 years and above. Meanwhile, pneumonia as a communicable disease was found to be the most common cause of death among both 0-14-year-old children and elderly people.

Validation of verbal autopsy: determination of cause of deaths in Malaysia 2013

Background

Mortality statistics by age, sex and cause are the foundation of basic health data required for health status assessment, epidemiological research and formation of health policy. Close to half the deaths in Malaysia occur outside a health facility, are not attended by medical personnel, and are given a lay opinion as to the cause of death, leading to poor quality of data from vital registration. Verbal autopsy (VA) is a very useful tool in diagnosing broad causes of deaths for events that occur outside health facilities. This article reports the development of the VA methods and our principal finding from a validation study.

Methods

A cross sectional study on nationally representative sample deaths that occurred in Malaysia during 2013 was used. A VA questionnaire suitable for local use was developed. Trained field interviewers visited the family members of the deceased at their homes and conducted face to face interviews with the next of kin. Completed questionnaires were reviewed by trained physicians who assigned multiple and underlying causes. Reference diagnoses for validation were obtained from review of medical records (MR) available for a sample of the overall study deaths.

Results

Corresponding MR diagnosis with matched sample of the VA diagnosis were available in 2172 cases for the validation study. Sensitivity scores were good (>75%) for transport accidents and certain cancers. Moderate sensitivity (50% - 75%) was obtained for ischaemic heart disease (64%) and cerebrovascular disease (72%). The validation sample for deaths due to major causes such as ischaemic heart disease, pneumonia, breast cancer and transport accidents show low cause-specific mortality fraction (CSMF) changes. The scores obtained for the top 10 leading site-specific cancers ranged from average to good.

Conclusion

We can conclude that VA is suitable for implementation for deaths outside the health facilities in Malaysia. This would reduce ill-defined mortality causes in vital registration data, and yield more accurate national mortality statistics.

Verbal Autopsy: Evaluation of Methods to Certify Causes of Death in Uganda

To assess different methods for determining cause of death from verbal autopsy (VA) questionnaire data, the intra-rater reliability of Physician-Certified Verbal Autopsy (PCVA) and the accuracy of PCVA, expert-derived (non-hierarchical) and data-driven (hierarchal) algorithms were assessed for determining common causes of death in Ugandan children. A verbal autopsy validation study was conducted from 2008-2009 in three different sites in Uganda. The dataset included 104 neonatal deaths (0-27 days) and 615 childhood deaths (1-59 months) with the cause(s) of death classified by PCVA and physician review of hospital medical records (the 'reference standard'). Of the original 719 questionnaires, 141 (20%) were selected for a second review by the same physicians; the repeat cause(s) of death were compared to the original,and agreement assessed using the Kappa statistic.Physician reviewers' refined non-hierarchical algorithms for common causes of death from existing expert algorithms, from which, hierarchal algorithms were developed. The accuracy of PCVA, non-hierarchical, and hierarchical algorithms for determining cause(s) of death from all 719 VA questionnaires was determined using the reference standard. Overall, intra-rater repeatability was high (83% agreement, Kappa 0.79 [95% CI 0.76-0.82]). PCVA performed well, with high specificity for determining cause of neonatal (>67%), and childhood (>83%) deaths, resulting in fairly accurate cause-specific mortality fraction (CSMF) estimates. For most causes of death in children, non-hierarchical algorithms had higher sensitivity, but correspondingly lower specificity, than PCVA and hierarchical algorithms, resulting in inaccurate CSMF estimates. Hierarchical algorithms were specific for most causes of death, and CSMF estimates were comparable to the reference standard and PCVA. Inter-rater reliability of PCVA was high, and overall PCVA performed well. Hierarchical algorithms performed better than non-hierarchical algorithms due to higher specificity and more accurate CSMF estimates. Use of PCVA to determine cause of death from VA questionnaire data is reasonable while automated data-driven algorithms are improved.

Contribution of suicide and injuries to pregnancy-related mortality in low-income and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Although suicide is one of the leading causes of deaths in young women in low-income and middle-income countries, the contribution of suicide and injuries to pregnancy-related mortality remains unknown.

METHODS

We did a systematic review to identify studies reporting the proportion of pregnancy-related deaths attributable to suicide or injuries, or both, in low-income and middle-income countries. We used a random-effects meta-analysis to calculate the pooled prevalence of pregnancy-related deaths attributable to suicide, stratified by WHO region. To account for the possible misclassification of suicide deaths as injuries, we calculated the pooled prevalence of deaths attributable to injuries, and undertook a sensitivity analysis reclassifying the leading methods of suicides among women in low-income and middle-income countries (burns, poisoning, falling, or drowning) as suicide.

FINDINGS

We identified 36 studies from 21 countries. The pooled total prevalence across the regions was 1·00% for suicide (95% CI 0·54-1·57) and 5·06% for injuries (3·72-6·58). Reclassifying the leading suicide methods from injuries to suicide increased the pooled prevalence of pregnancy-related deaths attributed to suicide to 1·68% (1·09-2·37). Americas (3·03%, 1·20-5·49), the eastern Mediterranean region (3·55%, 0·37-9·37), and the southeast Asia region (2·19%, 1·04-3·68) had the highest prevalence for suicide, with the western Pacific (1·16%, 0·00-4·67) and Africa (0·65%, 0·45-0·88) regions having the lowest.

INTERPRETATION

The available data suggest a modest contribution of injuries and suicide to pregnancy-related mortality in low-income and middle-income countries with wide regional variations. However, this study might have underestimated suicide deaths because of the absence of recognition and inclusion of these causes in eligible studies. We recommend that injury-related and other co-incidental causes of death are included in the WHO definition of maternal mortality to promote measurement and effective intervention for reduction of maternal mortality in low-income and middle-income countries.

FUNDING

National Institute of Mental Health.

The effect of health-facility admission and skilled birth attendant coverage on maternal survival in India: a case-control analysis

Background

Research in areas of low skilled attendant coverage found that maternal mortality is paradoxically higher in women who seek obstetric care. We estimated the effect of health-facility admission on maternal survival, and how this effect varies with skilled attendant coverage across India.

Methods/Findings

Using unmatched population-based case-control analysis of national datasets, we compared the effect of health-facility admission at any time (antenatal, intrapartum, postpartum) on maternal deaths (cases) to women reporting pregnancies (controls). Probability of maternal death decreased with increasing skilled attendant coverage, among both women who were and were not admitted to a health-facility, however, the risk of death among women who were admitted was higher (at 50% coverage, OR = 2.32, 95% confidence interval 1.85–2.92) than among those women who were not; while at higher levels of coverage, the effect of health-facility admission was attenuated. In a secondary analysis, the probability of maternal death decreased with increasing coverage among both women admitted for delivery or delivered at home but there was no effect of admission for delivery on mortality risk (50% coverage, OR = 1.0, 0.80–1.25), suggesting that poor quality of obstetric care may have attenuated the benefits of facility-based care. Subpopulation analysis of obstetric hemorrhage cases and report of ‘excessive bleeding’ in controls showed that the probability of maternal death decreased with increasing skilled attendant coverage; but the effect of health-facility admission was attenuated (at 50% coverage, OR = 1.47, 0.95–1.79), suggesting that some of the effect in the main model can be explained by women arriving at facility with complications underway. Finally, highest risk associated with health-facility admission was clustered in women with education 8 years.

Conclusions

The effect of health-facility admission did vary by skilled attendant coverage, and this effect appears to be driven partially by reverse causality; however, inequitable access to and possibly poor quality of healthcare for primary and emergency services appears to play a role in maternal survival as well.

Performance criteria for verbal autopsy-based systems to estimate national causes of death: development and application to the Indian Million Death Study

BACKGROUND

Verbal autopsy (VA) has been proposed to determine the cause of death (COD) distributions in settings where most deaths occur without medical attention or certification. We develop performance criteria for VA-based COD systems and apply these to the Registrar General of India's ongoing, nationally-representative Indian Million Death Study (MDS).

METHODS

Performance criteria include a low ill-defined proportion of deaths before old age; reproducibility, including consistency of COD distributions with independent resampling; differences in COD distribution of hospital, home, urban or rural deaths; age-, sex- and time-specific plausibility of specific diseases; stability and repeatability of dual physician coding; and the ability of the mortality classification system to capture a wide range of conditions.

RESULTS

The introduction of the MDS in India reduced the proportion of ill-defined deaths before age 70 years from 13% to 4%. The cause-specific mortality fractions (CSMFs) at ages 5 to 69 years for independently resampled deaths and the MDS were very similar across 19 disease categories. By contrast, CSMFs at these ages differed between hospital and home deaths and between urban and rural deaths. Thus, reliance mostly on urban or hospital data can distort national estimates of CODs. Age-, sex- and time-specific patterns for various diseases were plausible. Initial physician agreement on COD occurred about two-thirds of the time. The MDS COD classification system was able to capture more eligible records than alternative classification systems. By these metrics, the Indian MDS performs well for deaths prior to age 70 years. The key implication for low- and middle-income countries where medical certification of death remains uncommon is to implement COD surveys that randomly sample all deaths, use simple but high-quality field work with built-in resampling, and use electronic rather than paper systems to expedite field work and coding.

CONCLUSIONS

Simple criteria can evaluate the performance of VA-based COD systems. Despite the misclassification of VA, the MDS demonstrates that national surveys of CODs using VA are an order of magnitude better than the limited COD data previously available.

Maternal mortality in India: causes and healthcare service use based on a nationally representative survey

BACKGROUND

Data on cause-specific mortality, skilled birth attendance, and emergency obstetric care access are essential to plan maternity services. We present the distribution of India's 2001-2003 maternal mortality by cause and uptake of emergency obstetric care, in poorer and richer states.

METHODS AND FINDINGS

The Registrar General of India surveyed all deaths occurring in 2001-2003 in 1.1 million nationally representative homes. Field staff interviewed household members about events that preceded the death. Two physicians independently assigned a cause of death. Narratives for all maternal deaths were coded for variables on healthcare uptake. Distribution of number of maternal deaths, cause-specific mortality and uptake of healthcare indicators were compared for poorer and richer states. There were 10,041 all-cause deaths in women age 15-49 years, of which 1096 (11.1%) were maternal deaths. Based on 2004-2006 SRS national MMR estimates of 254 deaths per 100,000 live births, we estimated rural areas of poorer states had the highest MMR (397, 95%CI 385-410) compared to the lowest MMR in urban areas of richer states (115, 95%CI 85-146). We estimated 69,400 maternal deaths in India in 2005. Three-quarters of maternal deaths were clustered in rural areas of poorer states, although these regions have only half the estimated live births in India. Most maternal deaths were attributed to direct obstetric causes (82%). There was no difference in the major causes of maternal deaths between poorer and richer states. Two-thirds of women died seeking some form of healthcare, most seeking care in a critical medical condition. Rural areas of poorer states had proportionately lower access and utilization to healthcare services than the urban areas; however this rural-urban difference was not seen in richer states.

CONCLUSIONS

Maternal mortality and poor access to healthcare is disproportionately higher in rural populations of the poorer states of India.

Strengthening standardised interpretation of verbal autopsy data: the new InterVA-4 tool

Background

Verbal autopsy (VA) is the only available approach for determining the cause of many deaths, where routine certification is not in place. Therefore, it is important to use standards and methods for VA that maximise efficiency, consistency and comparability. The World Health Organization (WHO) has led the development of the 2012 WHO VA instrument as a new standard, intended both as a research tool and for routine registration of deaths.

Objective

A new public-domain probabilistic model for interpreting VA data, InterVA-4, is described, which builds on previous versions and is aligned with the 2012 WHO VA instrument.

Design

The new model has been designed to use the VA input indicators defined in the 2012 WHO VA instrument and to deliver causes of death compatible with the International Classification of Diseases version 10 (ICD-10) categorised into 62 groups as defined in the 2012 WHO VA instrument. In addition, known shortcomings of previous InterVA models have been addressed in this revision, as well as integrating other work on maternal and perinatal deaths.

Results

The InterVA-4 model is presented here to facilitate its widespread use and to enable further field evaluation to take place. Results from a demonstration dataset from Agincourt, South Africa, show continuity of interpretation between InterVA-3 and InterVA-4, as well as differences reflecting specific issues addressed in the design and development of InterVA-4.

Conclusions

InterVA-4 is made freely available as a new standard model for interpreting VA data into causes of death. It can be used for determining cause of death both in research settings and for routine registration. Further validation opportunities will be explored. These developments in cause of death registration are likely to substantially increase the global coverage of cause-specific mortality data.