evidence-based blog of Filippo Dibari

Posts Tagged ‘muac’

Is Middle-Upper Arm Circumference “normally” distributed? Secondary data analysis of 852 nutrition surveys

In Under-nutrition on November 27, 2016 at 3:25 am

by Frison S1, Checchi F2, Kerac M1, Nicholas J3.

Emerg Themes Epidemiol. 2016 May 4;13:7. doi: 10.1186/s12982-016-0048-9. eCollection 2016.

(download here)

Background

Wasting is a major public health issue throughout the developing world. Out of the 6.9 million estimated deaths among children under five annually, over 800,000 deaths (11.6 %) are attributed to wasting. Wasting is quantified as low Weight-For-Height (WFH) and/or low Mid-Upper Arm Circumference (MUAC) (since 2005). Many statistical procedures are based on the assumption that the data used are normally distributed. Analyses have been conducted on the distribution of WFH but there are no equivalent studies on the distribution of MUAC.

Methods

This secondary data analysis assesses the normality of the MUAC distributions of 852 nutrition cross-sectional survey datasets of children from 6 to 59 months old and examines different approaches to normalise “non-normal” distributions.

Results

The distribution of MUAC showed no departure from a normal distribution in 319 (37.7 %) distributions using the Shapiro–Wilk test. Out of the 533 surveys showing departure from a normal distribution, 183 (34.3 %) were skewed (D’Agostino test) and 196 (36.8 %) had a kurtosis different to the one observed in the normal distribution (Anscombe–Glynn test). Testing for normality can be sensitive to data quality, design effect and sample size. Out of the 533 surveys showing departure from a normal distribution, 294 (55.2 %) showed high digit preference, 164 (30.8 %) had a large design effect, and 204 (38.3 %) a large sample size. Spline and LOESS smoothing techniques were explored and both techniques work well. After Spline smoothing, 56.7 % of the MUAC distributions showing departure from normality were “normalised” and 59.7 % after LOESS. Box-Cox power transformation had similar results on distributions showing departure from normality with 57 % of distributions approximating “normal” after transformation. Applying Box-Cox transformation after Spline or Loess smoothing techniques increased that proportion to 82.4 and 82.7 % respectively.

Conclusion

This suggests that statistical approaches relying on the normal distribution assumption can be successfully applied to MUAC. In light of this promising finding, further research is ongoing to evaluate the performance of a normal distribution based approach to estimating the prevalence of wasting using MUAC.

1Department of Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT UK.

2Faculty of Public Health and Policy, LSHTM and Humanitarian Technical Unit, Save the Children, 207 Old Street, London, EC1V 9NR UK.

3Department of Medical Statistics, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT UK.

Mothers screening for malnutrition by mid-upper arm circumference is non-inferior to community health workers: results from a large-scale pragmatic trial in rural Niger

In Under-nutrition on September 14, 2016 at 9:59 pm

by Franck G.B. Alé, Kevin P.Q. Phelan, Hassan Issa, Isabelle Defourny, Guillaume Le Duc, Geza Harczi, Kader Issaley, Sani Sayadi, Nassirou Ousmane, Issoufou Yahaya, Mark Myatt, André Briend, Thierry Allafort-Duverger, Susan Shepherd and Nikki Blackwell

Abstract

Background

Community health workers (CHWs) are recommended to screen for acute malnutrition in the community by assessing mid-upper arm circumference (MUAC) on children between 6 and 59 months of age. MUAC is a simple screening tool that has been shown to be a better predictor of mortality in acutely malnourished children than other practicable anthropometric indicators. This study compared, under program conditions, mothers and CHWs in screening for severe acute malnutrition (SAM) by color-banded MUAC tapes.

Methods

This pragmatic interventional, non-randomized efficacy study took place in two health zones of Niger’s Mirriah District from May 2013 to April 2014. Mothers in Dogo (Mothers Zone) and CHWs in Takieta (CHWs Zone) were trained to screen for malnutrition by MUAC color-coded class and check for edema. Exhaustive coverage surveys were conducted quarterly, and relevant data collected routinely in the health and nutrition program. An efficacy and cost analysis of each screening strategy was performed.

Results

A total of 12,893 mothers and caretakers were trained in the Mothers Zone and 36 CHWs in the CHWs Zone, and point coverage was similar in both zones at the end of the study (35.14 % Mothers Zone vs 32.35 % CHWs Zone, p = 0.9484). In the Mothers Zone, there was a higher rate of MUAC agreement (75.4 % vs 40.1 %, p <0.0001) and earlier detection of cases, with median MUAC at admission for those enrolled by MUAC <115 mm estimated to be 1.6 mm higher using a smoothed bootstrap procedure. Children in the Mothers Zone were much less likely to require inpatient care, both at admission and during treatment, with the most pronounced difference at admission for those enrolled by MUAC < 115 mm (risk ratio = 0.09 [95 % CI 0.03; 0.25], p < 0.0001). Training mothers required higher up-front costs, but overall costs for the year were much lower ($8,600 USD vs $21,980 USD.)

Conclusions

Mothers were not inferior to CHWs in screening for malnutrition at a substantially lower cost. Children in the Mothers Zone were admitted at an earlier stage of SAM and required fewer hospitalizations. Making mothers the focal point of screening strategies should be included in malnutrition treatment programs.

Trial registration

The trial is registered with clinicaltrials.gov (Trial number NCT01863394).

Anthropometric predictors of mortality in undernourished adults in the Ajiep Feeding Programme in Southern Sudan

In Under-nutrition on July 8, 2013 at 8:03 pm

In Uncategorized on July 8, 2013 at 8:00 pm

by Abel H Irena, David A Ross, Peter Salama, and Steve Collins

Am J Clin Nutr August 2013

Abstract

Background: Various nutritional assessment tools are available to assess adult undernutrition, but few are practical in poorly served areas of low-income countries.

Objective: The objective was to assess the relation between midupper arm circumference (MUAC), weight, body mass index (BMI), and clinical assessment for edema in predicting mortality in adults with severe acute undernutrition.

Design: Demographic and anthropometric data that were collected in an observational study of 197 adults were analyzed. Participants were aged 18–59 y and were admitted to a therapeutic feeding center in Ajiep, Southern Sudan, during the height of the 1998 famine. Receiver operating curves were calculated and compared.

Results: The mean (±SD) age of the participants was 40.1 ±10.8 y, and the mean (±SD) MUAC, weight, and BMI (in kg/m2) were 16.4 ± 1.3 cm, 35.1 ± 5.2 kg, and 12.6 ± 1.5, respectively. The area under the receiver operating curve for MUAC (0.71) was higher (P = 0.01) than those of BMI (0.57) and weight (0.51). Mean age, weight, and BMI on admission did not differ between survivors and nonsurvivors (P > 0.17). MUAC and edema were independently associated with mortality. For every 1-cm increase in admission MUAC, the odds of subsequent mortality decreased by 58% (adjusted OR: 0.42; 95% CI: 0.28, 0.63; P < 0.001).

Conclusions: In this study, which was conducted at the height of a major famine among adults with extremely severe grades of undernutrition, MUAC and edema were better indicators of short-term prognosis than was BMI. Further studies are needed to define a critical MUAC threshold for the diagnosis of acute adult undernutrition.

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Is mid-upper arm circumference alone sufficient for deciding admission to a nutritional programme for childhood severe acute malnutrition in Bangladesh?

In Under-nutrition on April 13, 2013 at 8:03 am

Engy Alia, Rony Zachariaha, Zubair Shamsb, Lieven Vernaeveb, Petra Aldersc, Flavio Saliob,  Marcel Manzia, Malik Allaounac, Bertrand Draguezc, Pascale Delchevaleriec and Anthony D. Harries

Trans R Soc Trop Med Hyg (2013)

Abstract

Objectives Mid-upper arm circumference (MUAC) and weight-for-height Z-score (WHZ) identify different populations of children with severe acute malnutrition (SAM) with only some degree of overlap. In an urban slum in Bangladesh, we conducted a prospective cohort study on children assessed as being severely malnourished by WHZ (<–3) but not by MUAC (>115 mm), to: 1. Assess their nutritional outcomes, and 2. Report on morbidity and mortality.

Methods Children underwent 2-weekly prospective follow-up home visits for 3 months and their anthropometric evolution, morbidity and mortality were monitored.

Results Of 158 children, 21 did not complete follow-up (six were lost to follow-up and 15 changed residence). Of the remaining 137 children, nine (7%) required admission to the nutrition programme because of: MUAC dropping to <115 mm (5/9 children), weight loss ≥10% (1/9 children) and severe medical complications (3/9 children, of whom one died). Of the remaining 128 children who completed follow-up, 91 (66%) improved in nutritional status while 37 (27%) maintained a WHZ of <–3. Cough was less frequent among those whose nutritional status improved.

Conclusions It seems acceptable to rely on MUAC as a single assessment tool for case finding and for admission of children with SAM to nutritional programmes.

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NY Museum of Modern Art (MOMA) and…children acute malnutrition

In Uncategorized, Under-nutrition on September 10, 2012 at 8:15 am

An email from a dear friend nutritionist of mine recently informed me that…

“…the Museum of Modern Art (MOMA) in New York is doing an exhibition on the ‘century of the child: growing by design 1900-2000.

“…a diverse array of ideas, practitioners and objects illustrates how progressive design has informed the physical, intellectual, and emotional development of children….”

You can click here to see the web site.

But the interesting part of the email was to come:

“…if you click on designing better worlds 1960’s to 2000 there is a Middle-upper Arm Circumference tape (MUAC)…. Ok it is the wrong one, called a funny name and it’s origins are wrongly quoted. But it’s there and it has the red yellow and green that we so love. A design classic.. Pretty cool I thought.

“Lots of other interesting stuff there from lego and spacehoppers to a cardboard carseat (yes they include design mistakes!), Bennetons advert showing children labour, and one of those working wire cars made by a child in south africa, BUT definitely no scales or height boards… Hurrah!!

I hope you also will enjoy this event/web site. Have a nice week.

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Save the Children (NGO) about treatment of Acute Malnutrition: Minimum Reporting Package User Guidelines

In Under-nutrition on August 21, 2012 at 10:46 am

(download the entire doc)

“These minimum Reporting Package (MRP) User Guidelines are intended to outline the definitions, reporting categories and performance indicators for monitoring and reporting on three feeding programmes using the MRP software.

“The programmes are: targeted Supplementary Feeding Programmes (SFPs), Outpatient Therapeutic Programmes (OTPs) and Stabilisation Centres (SCs).

“There is also guidance on interpreting and taking action on programme performance indicators.

“The audience for the guidelines are nutrition programme coordinators and M&E staff of NGOs involved in the monitoring and reporting process.”

On this blog you can find more information about management of acute malnutrition, and ready to use foods for undernutrition treatment.
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Middle-upper arm circumference (MUAC) for nutritional surveillance in crisis-affected populations: development of a method

In Under-nutrition on April 30, 2012 at 3:43 pm

This is the PhD proposal of Séverine Frison (London School of Hygiene and Tropical Medicine). She undertakes her research together with Francesco Checchi and  Claudine Prudhon

Summary – Timely, sensitive, population-representative nutritional surveillance is crucial to detect nutritional emergencies in crisis-affected populations, and responding appropriately. Current approaches to nutritional surveillance mostly rely on regular anthropometric surveys, the results of which are interpreted alongside other crisis indicators such as mortality. However, there is little evidence on which to predicate the design of surveillance systems, and a variety of methods are employed in the field, with questionable impact, partly due to the infrequent nature of surveys.

Middle-upper arm circumference (MUAC) is known as a good predictor of mortality in children, and is increasingly adopted as the criterion for screening and admission to treatment programmes. Furthermore, MUAC is easier to measure than weight for height (WHZ), and may be more sensitive to changes in nutritional status. Despite this, it has not been used prominently in surveillance to date.

Here, we propose to develop a new method for nutritional surveillance in crisis-affected populations, based on measurement of the mean MUAC or the mean MUAC-for-age. Estimating the mean of these indices would entail lower sample size requirements than for prevalence surveys, improve the feasibility of data collection on the field, and allow for greater frequency and spatial resolution of surveillance. While mean MUAC trends could be interpreted separately, we wish here to study a potential method to infer GAM or SAM prevalence from the mean, thereby enabling quantification of programme needs. The proposed method is based on an assumption of normality and prior information about the population standard distribution of these indices, and relies on the ability of MUAC to capture oedema (kwashiorkor) cases. These assumptions need to be explored thoroughly.

The present project’s objectives are therefore to:

  1. Assemble a large dataset of surveys from a variety of settings that can be used to explore the statistical assumptions underlying the proposed method;
  2. Identify appropriate geographic strata into which to classify the surveys, and, more generally, regions of the world where nutritional surveys are undertaken, such that the variability of the SD of MUAC and MUAC-for-age within any given geographic stratum is minimised;
  3. Examine the association between MUAC or MUAC-for-age and oedema (as a sign of kwashiorkor), so as to investigate whether MUAC-based cut-offs for GAM or SAM capture oedema cases, and, if not, whether corrections can be applied to estimates based on MUAC alone in order to account for the prevalence of oedema;
  4. Examine the normality of MUAC and MUAC-for-age distributions at the population level and in small samples, and if necessary apply transformations to the data in order to achieve normality;
  5. Quantify and describe the SD of MUAC and MUAC-for-age across all surveys and within geographic strata, and assess how variability in SD would affect the precision of the proposed method;
  6. Investigate empirically the feasibility of using SDs of MUAC and MUAC-for-age from small sample size surveys directly by testing the stability of the SDs using a bootstrap method.
  7. Compare the appropriateness of MUAC versus MUAC-for-age cut-offs, by considering the degree of precision expected with either index if the proposed method is applied, as well as the relevance of either index for field operations.

We propose to accomplish the above objectives through extensive data analysis of at least 500 previously performed surveys from various areas of the world, livelihood zones and body shape strata. If successful, we envisage a second phase of development, consisting of defining sampling designs and sample size requirements for the proposed method to infer prevalence of GAM and SAM based on mean MUAC or MUAC-for-age.

The project will last 12 months, and is a collaboration between the London School of Hygiene and Tropical Medicine and the Health and Nutrition Tracking Service.

(Severine gave me the “green light” to publish this here)

 

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