Mortality and cause of death in the Pacific

Abstract

Accurate data on mortality levels and causes of death is critical to assist governments to improve the health of their populations; by identifying priority areas for intervention, leveraging resources for such interventions, and to monitor the impact and effectiveness of health programs. To date, there has been little data available to agencies on mortality and causes of death in the Pacific Islands, and there is significant disparity in published estimates, with many considered implausible. Further, there are indications that improvements in life expectancy (LE) across the region have stagnated in contrast to previously published estimates, most likely as a consequence of premature adult mortality from non-communicable diseases (NCDs).In this research, routine vital registration collections from Pacific Island countries are examined to determine whether these data can improve our understanding of mortality and causes of death in the region. The work presents a review of available data, examines the potential flaws and biases in the data collections, and examines the methods best suited to working with the identified collections to generate valid, reliable estimates of mortality level and cause of death, disaggregated by age group and sex. Due to the scale and diversity of the Pacific Islands, six countries representing a broad range of population size, level of development, and all three sub-regions were selected for review. These were: Nauru, Fiji, Kiribati, Palau, Tonga and Vanuatu.Reporting systems were evaluated to identify potential impacts on the quality and completeness of available data using an assessment framework that considers the societal, administrative and system (administrative, technical and ownership) influences on the reporting system. Substantially more data was found to be available than has been previously analysed or published. Medical certificates of death are completed for some deaths in all of the study countries, and are required for all deaths in Nauru, Fiji, Tonga and Palau.Analytical strategies for deriving estimates of mortality level by age and sex were selected from available approaches based on the system assessments, data available and level of migration. Methods employed included direct calculation of mortality level and evaluation of trends over time (Nauru and Palau), evaluation of published data to establish plausible trends (Fiji and Tonga), direct demographic methods to assess completeness - the Brass Growth Balance analysis (Fiji), and capture-recapture analyses (Tonga and Kiribati). Only Vanuatu had insufficient data from routine collection systems to reliably generate mortality estimates. Findings from the use of model life tables in comparison to mortality estimates from empirical data in the other study countries were therefore reviewed to evaluate the plausibility of published estimates of mortality level from Vanuatu.Estimates of cause–specific mortality were calculated directly from the medical certificate data for Palau where the system review indicated a high level of content validity. A medical record review was conducted in both Tonga and Nauru, and a death certificate review conducted in Fiji where access to the medical records was not possible. Other routine collections for cause of death were explored in Vanuatu and Kiribati where medical certificates were not available for all deaths.Findings from this study demonstrate that LE across the selected countries is lower than previously reported, but that this indicates a stagnation in LE rather than a reversal in LE improvements as earlier estimates did not adequately account for premature adult mortality. Estimates of LE for males ranged from 49 and 58 years in Kiribati (2005-2009) for males and females respectively, to 65 and 70 years for males and females respectively in Tonga (2005-2008) and Vanuatu (2005). Adult mortality was high across all countries, with NCDs the leading cause of death in adults aged 15-59 years in all countries. In Tonga, it has been possible to demonstrate significant increases in age-standardised mortality, from the early 2000’s to the present, in ischaemic heart disease, diabetes and lung cancer.Estimates of IMR and U5 mortality remain fairly high in Kiribati at 52 and 72 deaths per 1,000 live births respectively, and in Nauru at 28 and 46 deaths per 1,000 live births respectively. Causes of death in children 0-4 years in both countries reflect a high proportion of deaths from preventable causes: including perinatal conditions, malnutrition and infectious diseases. For all other study countries, IMR was estimated to be below 20 deaths per 1,000 live births. These figures indicate that while there are still gains to be made in improving child health in the region, infant and child mortality are not the major influence contributing to the low life expectancies seen across countries.Despite a need for improvements in routine reporting systems to address poor coverage, completeness and reporting practices, locally generated empirical data from routine reporting systems was found to be able to generate plausible estimates of mortality and add substantially to our understanding of cause of death in the region.