Jean Pierre Habicht

Evidence-Based Public Health: Moving Beyond Randomized Trials

Randomized controlled trials (RCTs) are essential for evaluating the efficacy of clinical interventions, where the causal chain between the agent and the outcome is relatively short and simple and where results may be safely extrapolated to other settings. However, causal chains in public health interventions are complex, making RCT results subject to effect modification in different populations. Both the internal and external validity of RCT findings can be greatly enhanced by observational studies using adequacy or plausibility designs. For evaluating large-scale interventions, studies with plausibility designs are often the only feasible option and may provide valid evidence of impact. There is an urgent need to develop evaluation standards and protocols for use in circumstances where RCTs are not appropriate.

Understanding hunger and developing indicators to assess it in women and children

Abstract The lack of an operational definition for hunger has been frequently cited as a barrier to progress in addressing the problem. The purposes of this research were to develop an understanding of hunger from the perspective of women who had experienced it and to construct and evaluate indicators to measure hunger directly in similar populations. In-depth interviews were conducted with 32 women of childbearing age from rural and urban areas of Upstate New York. Qualitative analysis of the responses yielded a conceptualization of hunger that included two levels: the individual and household. Hunger at each of these levels had quantitative, qualitative, psychological and social components. These women also viewed hunger as a managed process. Based on this conceptualization of hunger, survey items were developed and evaluated, using data from a questionnaire administered to 189 women from the same geographical area. Three scales, one each for household, womens, and childrens hunger, emerged and were found to be valid and reliable indicators for measuring hunger directly in this population.

Reducing child mortality: can public health deliver?

This is the third paper in the series on child survival. The second paper in the series, published last week, concluded that in the 42 countries with 90% of child deaths worldwide in 2000, 63% of these deaths could have been prevented through full implementation of a few known and effective interventions. Levels of coverage with these interventions are still unacceptably low in most low-income and middle-income countries. Worse still, coverage for some interventions, such as immunisations and attended delivery, are stagnant or even falling in several of the poorest countries. This paper highlights the importance of separating biological or behavioural interventions from the delivery systems required to put them in place, and the need to tailor delivery strategies to the stage of health-system development. We review recent initiatives in child health and discuss essential aspects of delivery systems, including: need for data at the subnational level to support health planning; regular monitoring of provision and use of health services, and of intervention coverage; and the need to achieve high and equitable coverage with selected interventions. Community-based initiatives can extend the delivery of interventions in areas where health services are hard to access, but strengthening national health systems should be the long-term aim. The millennium development goal for child survival can be achieved, but only if strategies for delivery interventions are greatly improved and scaled-up.

Effect of the Integrated Management of Childhood Illness strategy on childhood mortality and nutrition in a rural area in Bangladesh: a cluster randomised trial

BACKGROUND WHO and UNICEF launched the Integrated Management of Childhood Illness (IMCI) strategy in the mid-1990s to reduce deaths from diarrhoea, pneumonia, malaria, measles, and malnutrition in children younger than 5 years. We assessed the effect of IMCI on health and nutrition of children younger than 5 years in Bangladesh. METHODS In this cluster randomised trial, 20 first-level government health facilities in the Matlab subdistrict of Bangladesh and their catchment areas (total population about 350 000) were paired and randomly assigned to either IMCI (intervention; ten clusters) or usual services (comparison; ten clusters). All three components of IMCI-health-worker training, health-systems improvements, and family and community activities-were implemented beginning in February, 2002. Assessment included household and health facility surveys tracking intermediate outputs and outcomes, and nutrition and mortality changes in intervention and comparison areas. Primary endpoint was mortality in children aged between 7 days and 59 months. Analysis was by intention to treat. This study is registered, number ISRCTN52793850. FINDINGS The yearly rate of mortality reduction in children younger than 5 years (excluding deaths in first week of life) was similar in IMCI and comparison areas (8.6%vs 7.8%). In the last 2 years of the study, the mortality rate was 13.4% lower in IMCI than in comparison areas (95% CI -14.2 to 34.3), corresponding to 4.2 fewer deaths per 1000 livebirths (95% CI -4.1 to 12.4; p=0.30). Implementation of IMCI led to improved health-worker skills, health-system support, and family and community practices, translating into increased care-seeking for illnesses. In IMCI areas, more children younger than 6 months were exclusively breastfed (76%vs 65%, difference of differences 10.1%, 95% CI 2.65-17.62), and prevalence of stunting in children aged 24-59 months decreased more rapidly (difference of differences -7.33, 95% CI -13.83 to -0.83) than in comparison areas. INTERPRETATION IMCI was associated with positive changes in all input, output, and outcome indicators, including increased exclusive breastfeeding and decreased stunting. However, IMCI implementation had no effect on mortality within the timeframe of the assessment. FUNDING Bill & Melinda Gates Foundation, WHOs Department of Child and Adolescent Health and Development, and US Agency for International Development.

The multi-country evaluation of the integrated management of childhood illness strategy: lessons for the evaluation of public health interventions.

The Multi-Country Evaluation of the Integrated Management of Childhood Illness (IMCI) includes studies of the effectiveness, cost, and impact of the IMCI strategy in Bangladesh, Brazil, Peru, Tanzania, and Uganda. Seven questions were addressed when the evaluation was designed: who would be in charge, through what mechanisms IMCI could affect child health, whether the focus would be efficacy or effectiveness, what indicators would be measured, what types of inference would be made, how costs would be incorporated, and what elements would constitute the plan of analysis. We describe how these questions were answered, the challenges encountered in implementing the evaluation, and the 5 study designs. The methodological insights gained can improve future evaluations of public health programs.

Improving antimicrobial use among health workers in first-level facilities: results from the Multi-Country Evaluation of the Integrated Management of Childhood Illness strategy

OBJECTIVE The objective of this study was to assess the effect of Integrated Management of Childhood Illness (IMCI) case management training on the use of antimicrobial drugs among health-care workers treating young children at first-level facilities. Antimicrobial drugs are an essential child-survival intervention. Ensuring that children younger than five who need these drugs receive them promptly and correctly can save their lives. Prescribing these drugs only when necessary and ensuring that those who receive them complete the full course can slow the development of antimicrobial resistance. METHODS Data collected through observation-based surveys in randomly selected first-level health facilities in Brazil, Uganda and the United Republic of Tanzania were statistically analysed. The surveys were carried out as part of the multi-country evaluation of IMCI effectiveness, cost and impact (MCE). FINDINGS Results from three MCE sites show that children receiving care from health workers trained in IMCI are significantly more likely to receive correct prescriptions for antimicrobial drugs than those receiving care from workers not trained in IMCI. They are also more likely to receive the first dose of the drug before leaving the health facility, to have their caregiver advised how to administer the drug, and to have caregivers who are able to describe correctly how to give the drug at home as they leave the health facility. CONCLUSIONS IMCI case management training is an effective intervention to improve the rational use of antimicrobial drugs for sick children visiting first-level health facilities in low-income and middle-income countries.

Iron Supplementation of Young Children: Learning from the New Evidence:

High iron needs and low-iron diets combine to make early childhood one of the highest risk periods for iron deficiency. Recommendations for iron supplementation for this age group have been based on positive effects on anemia and child development. In contrast, the evidence regarding growth and morbidity outcomes has been equivocal, with some evidence of risk. The new evidence from Nepal and Zanzibar is reviewed, and possible interpretations are discussed. The Zanzibar trial found significant adverse effects in the overall population with poor malaria services and substantial benefit to iron-deficient children (the majority) in an area where access to treatments was provided. Cost-effectiveness analysis suggests that targeting supplements to iron-deficient children in Zanzibar may not increase costs (relative to universal supplementation) and would increase benefit. Operations research is needed to test this. We conclude with three options for maximizing the benefits and minimizing the risks of iron supplements.

Testing the effects of nutrient deficiencies on behavioral performance.

The association between specific nutrient deficiencies and poor performance on behavioral tests has been documented for several nutrients. The determination of causality, however, remains elusive. This paper presents the essential criteria for a valid test of causality. Findings from experimental studies in which a nutritional treatment was randomly allocated can be summarized in a statistical statement about the probability that the nutrient treatment caused the behavioral response. Criteria for assessing the internal validity of these studies are examined in terms of whether alleviation of a nutrient deficiency did or did not produce a detectable behavioral response. The plausibility of such a causal inference is dependent on its congruency with known or theorized biological and behavioral mechanisms. External validity describes the extent to which inferences from internally valid studies may be applicable to other populations or circumstances. In addition to these scientific considerations, some of the ethical issues of nutrient-treatment trials are also discussed. All of these considerations provide a better basis for judging whether public health action would be worthwhile than do observed associations that could actually be due to other causes.