Impact of Insecticide-Treated Net Ownership on All-Cause Child Mortality in Malawi, 2006–2010

Abstract

Abstract.Insecticide-treated nets (ITNs) have been shown to be highly effective at reducing malaria morbidity and mortality in children. However, there are limited studies that assess the association between increasing ITN coverage and child mortality over time, at the national level, and under programmatic conditions. Two analytic approaches were used to examine this association: a retrospective cohort analysis of individual children and a district-level ecologic analysis. To evaluate the association between household ITN ownership and all-cause child mortality (ACCM) at the individual level, data from the 2010 Demographic and Health Survey (DHS) were modeled in a Cox proportional hazards framework while controlling for numerous environmental, household, and individual confounders through the use of exact matching. To evaluate population-level association between ITN ownership and ACCM between 2006 and 2010, program ITN distribution data and mortality data from the 2006 Multiple Indicator Cluster Survey and the 2010 DHS were aggregated at the district level and modeled using negative binomial regression. In the Cox model controlling for household, child and maternal health factors, children between 1 and 59 months in households owning an ITN had significantly lower mortality compared with those without an ITN (hazard ratio = 0.75, 95% confidence interval [CI] = 0.62–90). In the district-level model, higher ITN ownership was significantly associated with lower ACCM (incidence rate ratio = 0.77; 95% CI = 0.60–0.98). These findings suggest that increasing ITN ownership may have contributed to the decline in ACCM during 2006–2010 in Malawi and represent a novel use of district-level data from nationally representative surveys.

Malaria Control Interventions Contributed to Declines in Malaria Parasitemia, Severe Anemia, and All-Cause Mortality in Children Less Than 5 Years of Age in Malawi, 2000–2010

“…We also found that household ITN ownership was associated with increased child survival using a Cox proportional hazards model and a district-level platform model presented in the accompanying paper by Florey and others. 16 It should be noted that the Cox proportional hazards model assesses individual level associations, which could be influenced by residual confounding and may not translate directly to population level impact. However, given there are numerous controlled studies that have assessed the association between ITNs and malaria morbidity and mortality, 8,44 it was important to assess the association in Malawi under programmatic conditions where distribution of ITNs was not under the control of a study, but relied on the routine distribution systems operating in country (retail, social marketing, ANC/EPI routine distribution, and mass campaigns).…”

“…Multivariable models support this claim; ITN ownership is associated with improved child survival in Malawi. 16 In addition, ITN ownership was found to be protective against malaria morbidity measures (severe anemia and parasitemia in children 6–30 months of age). Taken together this evidence suggests that malaria control interventions in Malawi likely contributed to reductions in ACCM during 2000–2010.…”

“… 13 This evaluation design was strengthened by using logistic regression models to assess the strength of association between household ITN ownership and malaria parasitemia and severe anemia among child household members during the evaluation period, two malaria morbidity measures which are in the causal pathway between malaria control interventions and changes in ACCM ( Figure 2 ). Multivariable regression models were also used to evaluate the association between household ITN ownership and ACCM under programmatic conditions which are separately reported by Florey and others 16 in this journal supplement.…”

Implementing Impact Evaluations of Malaria Control Interventions: Process, Lessons Learned, and Recommendations

“…In addition to the impact evaluation reports themselves, in some countries the results from the impact evaluations were used to produce two additional types of documents: RBM Progress and Impact (P and I) Series Country Focus reports 18,19 and scientific journal articles. 11,16,20–22 The RBM P and I reports, which were advocacy-focused documents, afforded an opportunity to present findings from the impact evaluation in a clear and concise format, to tailor the report to a wider audience (e.g., politicians, media, advocates, development partners), and to share lessons learned during the scale-up phase of malaria control interventions in a given country. Results from the evaluation in mainland Tanzania were also used as a country showcase for impact in the Global Fund results reports.…”

Evaluating malaria programmes in moderate- and low-transmission settings: practical ways to generate robust evidence

“…Since the 2000s, there have been efforts to design and implement appropriate methodologies to assess the impact of malaria intervention scale-up in high transmission settings, often by tracking changes in all-cause child mortality (ACCM) [3,4]. These approaches have been used successfully in several malaria-endemic countries [5][6][7][8]. However, different evaluation approaches are needed in countries where transmission is low or heterogeneous.…”