Presented at the November 2013 ASTMH Conference.

1. Association between increasing ITN use and reductions in moderate-to-severe
anemia in children 6-23 months of age: A multi-country decomposition analysis
Lia S. Florey¹; Cameron Taylor¹; Yazoume Ye2; Fred Arnold¹
¹ICF International, MEASURE DHS; 2ICF International, MEASURE Evaluation
Background
Methods
Interpretation
Acknowledgments
Assessing the success of malaria control interventions is difficult due to the challenge of measuring malaria-specific outcomes. In contrast, hemoglobin levels
are relatively simple to measure, and although not highly specific to malaria, moderate-to-severe anemia (hemoglobin < 8 g/dL) is a common symptom of
the disease. Approximately 15% of anemia in pre-school-age children is attributable to malaria. This analysis was done to describe distributions and trends in
nationally representative estimates of ITN use and moderate-to-severe anemia over periods of ITN scale-up and to assess the impact of ITN use on
prevalence of moderate-to-severe anemia in children age 6-23 months.
• Data from 11 countries with two or more DHS surveys between 2001 and 2011
containing information on insecticide-treated net (ITN) use and hemoglobin
levels in children 6-23 months of age.
Data sources
• Multivariable logistic regression models on pooled data comparing baseline and
endline were used to identify differential effects of ITN use on anemia between
the two periods.
• Multivariate Oaxaca-Blinder decomposition for nonlinear response models with
deviation contrast normalization for categorical variables were used to estimate
the proportion of the decline in anemia prevalence over time due to increases in
ITN use.
In most countries the prevalence of moderate-to-severe
anemia in children 6-23 months of age has decreased over a
period in which ITN use has increased dramatically. The
changes in ITN use explained the greatest proportion of the
total change in anemia between baseline and endline as
compared to other covariates. Results suggest that scale-up
of malaria control interventions are likely to have measurable
impact on moderate-to-severe anemia and consequently that
anemia may be a useful impact measure.
Analysis
Funding for this research was provided by the United States Agency for International Development (USAID) through the
MEASURE DHS project, implemented by ICF International in Calverton, Maryland, USA. Views expressed are those of
the authors and do not necessarily reflect the views of USAID or the United States Government.
Results
Figure 1: Change in anemia between baseline and endline surveys
863
Table 1: Pooled, multivariable model of anemia
0
5
10
15
20
25
30
35
40
45
baseline endline
0
10
20
30
40
50
60
70
80
90
baseline endline
Figure 2: Change in ITN use between baseline and endline surveys
Table 2: Adjusted odds ratio of anemia by ITN use (Y/N)
Table 3: Decomposition model results
* <0.05; ** < 0.01; *** <0.001
OR 95% CI p-value
ITN Use
No Ref.
Yes 0.81 0.70 0.94 0.005
Residence
Urban Ref.
Rural 1.22 1.02 1.47 0.034
Wealth Quintile
Lowest Ref.
Second 0.92 0.80 1.07 0.291
Middle 0.83 0.70 0.97 0.022
Fourth 0.73 0.61 0.87 0.001
Highest 0.53 0.41 0.67 <0.001
Multiple Birth Status
Singleton Ref.
Twin or more 2.19 1.56 3.06 <0.001
Mother's Education
No education Ref.
Primary 0.92 0.81 1.05 0.222
Secondary+ 0.83 0.68 1.02 0.075
Child's Sex
Male Ref.
Female 0.83 0.75 0.93 0.001
Child's Age
6-11 months Ref.
12-17 months 0.99 0.87 1.12 0.863
18-23 months 0.77 0.67 0.88
Recent Fever
No Ref.
Yes 1.82 1.62 2.05 <0.001
Total N 22,802
Endowments Coefficient
Household-level
ITN Use 1.102 * 0.69
Rural Residence -0.054 ** 7.2 *
Lowest Wealth Quintile 0.027 * -0.36
Second Wealth Quintile -0.01 * -0.27
Middle Wealth Quintile 0.002 -0.25
Fourth Wealth Quintile 0.001 0.28
Highest Wealth Quintile 0.051 * 0.41
Mother-level
No Education 0.059 ** 0.1
Primary 0.002 0.87
Secondary or More 0.039 -0.39
Child-level
Multiple Birth -0.023 *** -0.01
Female 0.011 2.14
6-11 Months 0.001 -0.4
12-17 Months -0.001 * 0.16
18-23 Months 0.002 ** 0.22
Recent Fever 0.247 *** -0.03
Constant -5.98
Total 1.46 ** 4.4 ***
Percent 24.9 75.1
Anemia difference (%) -5.8 ***
*Adjusted for urban-rural residence, wealth quintile, multiple births, mother's education, sex, age, mother's age, and recent fever.
Baseline pooled I2 test for heterogeneity = 33.8% (p=0.138). Endline pooled I2 test for heterogeneity = 0.0% (p=0.661). Overall pooled I2
test for heterogeneity = 10.9% (p=0.319).
© Bonnie Gillespie, courtesy of Photoshare