Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power
The WHO has recently debated whether to reaffirm its long-standing recommendation of mass drug administration (MDA) in areas with more than 20 percent prevalence of soil-transmitted helminths (hookworm, whipworm, and roundworm). There is consensus...
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World Bank, Washington, DC
2017
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okr-10986-258202021-06-08T14:42:46Z Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power Croke, Kevin Hicks, Joan Hamory Hsu, Eric Kremer, Michael Miguel, Edward child nutrition deworming meta-analysis early childhood development cost-benefit analysis mass drug administration The WHO has recently debated whether to reaffirm its long-standing recommendation of mass drug administration (MDA) in areas with more than 20 percent prevalence of soil-transmitted helminths (hookworm, whipworm, and roundworm). There is consensus that the relevant deworming drugs are safe and effective, so the key question facing policymakers is whether the expected benefits of MDA exceed the roughly $0.30 per treatment cost. The literature on long run educational and economic impacts of deworming suggests that this is the case. However, a recent meta-analysis by Taylor-Robinson et al. (2015), (hereafter TMSDG), disputes these findings. The authors conclude that while treatment of children known to be infected increases weight by 0.75 kg (95 percent CI: 0.24, 1.26; p=0.0038), there is substantial evidence that MDA has no impact on weight or other child outcomes. This paper updates the TMSDG analysis by including studies omitted from that analysis and extracting additional data from included studies, and finds that the TMSDG analysis is underpowered: Power is inadequate to rule out weight gain effects that would make MDA cost effective relative to comparable interventions in similar populations, and underpowered to reject the hypothesis that the effect of MDA is different from the effect that might expected, given deworming's effects on those known to be infected. The hypothesis of a common zero effect of multiple-dose MDA deworming on child weight at longest follow-up is rejected at the 10 percent level using the TMSDG dataset, and with a p value < 0.001 using the updated sample. In the full sample, including studies in settings where prevalence is low enough that the WHO does not recommend deworming, the average effect on child weight is 0.134 kg (95 percent CI: 0.031, 0.236, random effects). In environments with greater than 20 percent prevalence, where the WHO recommends mass treatment, the average effect on child weight is 0.148 kg (95 percent CI: 0.039, 0.258). The implied average effect of MDA on infected children in the full sample is 0.301 kg. At 0.22 kg per U.S. dollar, the estimated average weight gain per dollar is more than 35 times that from school feeding programs as estimated in RCTs. Under-powered meta-analyses are common in health research, and this methodological issue will be increasingly important as growing numbers of economists and other social scientists conduct meta-analysis. 2017-01-05T22:50:36Z 2017-01-05T22:50:36Z 2016-12 Working Paper http://documents.worldbank.org/curated/en/926411482169164466/Does-mass-deworming-affect-child-nutrition-meta-analysis-cost-effectiveness-and-statistical-power http://hdl.handle.net/10986/25820 English en_US Policy Research Working Paper;No. 7921 CC BY 3.0 IGO http://creativecommons.org/licenses/by/3.0/igo World Bank World Bank, Washington, DC Publications & Research Publications & Research :: Policy Research Working Paper |
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Foreign Institution |
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Digital Repositories |
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English en_US |
| topic |
child nutrition deworming meta-analysis early childhood development cost-benefit analysis mass drug administration |
| spellingShingle |
child nutrition deworming meta-analysis early childhood development cost-benefit analysis mass drug administration Croke, Kevin Hicks, Joan Hamory Hsu, Eric Kremer, Michael Miguel, Edward Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power |
| relation |
Policy Research Working Paper;No. 7921 |
| description |
The WHO has recently debated whether to
reaffirm its long-standing recommendation of mass drug
administration (MDA) in areas with more than 20 percent
prevalence of soil-transmitted helminths (hookworm,
whipworm, and roundworm). There is consensus that the
relevant deworming drugs are safe and effective, so the key
question facing policymakers is whether the expected
benefits of MDA exceed the roughly $0.30 per treatment cost.
The literature on long run educational and economic impacts
of deworming suggests that this is the case. However, a
recent meta-analysis by Taylor-Robinson et al. (2015),
(hereafter TMSDG), disputes these findings. The authors
conclude that while treatment of children known to be
infected increases weight by 0.75 kg (95 percent CI: 0.24,
1.26; p=0.0038), there is substantial evidence that MDA has
no impact on weight or other child outcomes. This paper
updates the TMSDG analysis by including studies omitted from
that analysis and extracting additional data from included
studies, and finds that the TMSDG analysis is underpowered:
Power is inadequate to rule out weight gain effects that
would make MDA cost effective relative to comparable
interventions in similar populations, and underpowered to
reject the hypothesis that the effect of MDA is different
from the effect that might expected, given deworming's
effects on those known to be infected. The hypothesis of a
common zero effect of multiple-dose MDA deworming on child
weight at longest follow-up is rejected at the 10 percent
level using the TMSDG dataset, and with a p value < 0.001
using the updated sample. In the full sample, including
studies in settings where prevalence is low enough that the
WHO does not recommend deworming, the average effect on
child weight is 0.134 kg (95 percent CI: 0.031, 0.236,
random effects). In environments with greater than 20
percent prevalence, where the WHO recommends mass treatment,
the average effect on child weight is 0.148 kg (95 percent
CI: 0.039, 0.258). The implied average effect of MDA on
infected children in the full sample is 0.301 kg. At 0.22 kg
per U.S. dollar, the estimated average weight gain per
dollar is more than 35 times that from school feeding
programs as estimated in RCTs. Under-powered meta-analyses
are common in health research, and this methodological issue
will be increasingly important as growing numbers of
economists and other social scientists conduct meta-analysis. |
| format |
Working Paper |
| author |
Croke, Kevin Hicks, Joan Hamory Hsu, Eric Kremer, Michael Miguel, Edward |
| author_facet |
Croke, Kevin Hicks, Joan Hamory Hsu, Eric Kremer, Michael Miguel, Edward |
| author_sort |
Croke, Kevin |
| title |
Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power |
| title_short |
Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power |
| title_full |
Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power |
| title_fullStr |
Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power |
| title_full_unstemmed |
Does Mass Deworming Affect Child Nutrition? : Meta-Analysis, Cost-Effectiveness, and Statistical Power |
| title_sort |
does mass deworming affect child nutrition? : meta-analysis, cost-effectiveness, and statistical power |
| publisher |
World Bank, Washington, DC |
| publishDate |
2017 |
| url |
http://documents.worldbank.org/curated/en/926411482169164466/Does-mass-deworming-affect-child-nutrition-meta-analysis-cost-effectiveness-and-statistical-power http://hdl.handle.net/10986/25820 |
| _version_ |
1764460232402010112 |