Infant and child mortality in relation to malaria transmission in KEMRI/CDC HDSS, Western Kenya: validation of verbal autopsy
Infant and child mortality in relation to malaria transmission in KEMRI/CDC HDSS, Western Kenya: validation of verbal autopsy
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DOI：
10.1186/s12936-018-2184-x
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发表时间：
2018-01-18
期刊：
影响因子：
3
通讯作者：
Vounatsou, Penelope
中科院分区：
文献类型：
--
作者：
Amek, Nyaguara O.;Van Eijk, Annemieke;Vounatsou, Penelope
背景：减少疟疾传播是许多疟疾控制规划的目标。具体减少传播可以减少多少死亡率，目前还知之甚少。口头尸检（VA）被广泛用于估计疟疾特异性死亡率，但不能可靠地区分疟疾和其他发热性疾病。疟疾造成的总死亡率包括直接和间接死亡。目前还不清楚什么比例的死亡，避免减少疟疾传播被归类为疟疾在VA。方法：无论是全因，病因特异性死亡率报告的VA为5岁以下的儿童，组装从KEMRI/疾病预防控制中心的健康和人口监测系统在锡亚亚县，肯尼亚西部农村的2002-2004年。这些与根据昆虫学数据的高分辨率时空地统计学建模对家庭恶性疟原虫昆虫接种率的估计有关。分析了全因死亡率和疟疾特异性死亡率（VA）与EIR、驱虫蚊帐使用（ITN）、社会经济地位（SES）和描述时空相关性的参数的关系。使用贝叶斯地统计学考克斯比例风险模型分析每个儿童的风险时间，并使用时间依赖性协变量。产出被用来估计VA在测量死亡率，可以归因于疟疾exposure.Results的诊断性能：在研究期间的总体5岁以下儿童死亡率为80每1000人年。VA指定了死亡总数的81%的死因，其中疟疾是除新生儿期外的主要死因。虽然通过VA评估未观察到疟疾特异性死亡率的趋势，但ITN使用与婴儿全因死亡率降低相关（风险比0.15，95%CI 0.02，0.63），EIR与全因死亡率和疟疾特异性死亡率密切相关。通过分析疟疾的发病率-反应关系，48.2%的死亡可归因于疟疾，但只有20.5%的VA指定疟疾为原因，估计VA的敏感性仅为26%。结论：降低恶性疟原虫传播强度的干预措施不仅能显著降低疟疾流行区5岁以下儿童的确诊死亡率，而且能显著降低其他原因导致的死亡率。在这种情况下，基于临床医生审查的VA工具大大低估了通过减少儿童期疟疾暴露可以避免的死亡人数，但具有相当高的特异性。这表明，减少疟疾传播的干预措施，如驱虫蚊帐，有可能使总体儿童死亡率降低两倍之多，这是根据增值服务估计的疟疾直接负担总额。
Background: Malaria transmission reduction is a goal of many malaria control programmes. Little is known of how much mortality can be reduced by specific reductions in transmission. Verbal autopsy (VA) is widely used for estimating malaria specific mortality rates, but does not reliably distinguish malaria from other febrile illnesses. Overall malaria attributable mortality includes both direct and indirect deaths. It is unclear what proportion of the deaths averted by reducing malaria transmission are classified as malaria in VA.Methods: Both all-cause, and cause-specific mortality reported by VA for children under 5 years of age, were assembled from the KEMRI/CDC health and demographic surveillance system in Siaya county, rural Western Kenya for the years 2002-2004. These were linked to household-specific estimates of the Plasmodium falciparum entomological inoculation rate (EIR) based on high resolution spatio-temporal geostatistical modelling of entomological data. All-cause and malaria specific mortality (by VA), were analysed in relation to EIR, insecticide-treated net use (ITN), socioeconomic status (SES) and parameters describing space-time correlation. Time at risk for each child was analysed using Bayesian geostatistical Cox proportional hazard models, with time-dependent covariates. The outputs were used to estimate the diagnostic performance of VA in measuring mortality that can be attributed to malaria exposure.Results: The overall under-five mortality rate was 80 per 1000 person-years during the study period. Eighty-one percent of the total deaths were assigned causes of death by VA, with malaria assigned as the main cause of death except in the neonatal period. Although no trend was observed in malaria-specific mortality assessed by VA, ITN use was associated with reduced all-cause mortality in infants (hazard ratio 0.15, 95% CI 0.02, 0.63) and the EIR was strongly associated with both all-cause and malaria-specific mortality. 48.2% of the deaths could be attributed to malaria by analysing the exposure-response relationship, though only 20.5% of VAs assigned malaria as the cause and the sensitivity of VAs was estimated to be only 26%. Although VAs assigned some deaths to malaria even in areas where there was estimated to be no exposure, the specificity of the VAs was estimated to be 85%.Conclusion: Interventions that reduce P. falciparum transmission intensity will not only significantly reduce malaria-diagnosed mortality, but also mortality assigned to other causes in under-5 year old children in endemic areas. In this setting, the VA tool based on clinician review substantially underestimates the number of deaths that could be averted by reducing malaria exposure in childhood, but has a reasonably high specificity. This suggests that malaria transmission-reducing interventions such as ITNs can potentially reduce overall child mortality by as much as twice the total direct malaria burden estimated from VAs.