Severely malnourished children with a low weight-for-height have a higher mortality than those with a low mid-upper-arm-circumference: I. Empirical data demonstrates Simpson’s paradox

Grellety, Emmanuel; Golden, Michael

doi:10.1186/s12937-018-0384-4

Cited by 28 publications

(34 citation statements)

References 85 publications

(52 reference statements)

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“…Our analysis documents considerable variability by survey within regions, and even within countries. Previous research has documented increased mortality risk among children with both WHZ2 and MUAC125 relative to those identified as malnourished by only one indicator; the relative risk of children with both WHZ2 and MUACZ2 has not been investigated [22]. Among malnourished children not identified by both indicators, MUACZ2 diagnosed more children as malnourished than WHZ2.…”

Section: Discussionmentioning

confidence: 99%

Concordance between estimates of acute malnutrition measured by weight-for-height and by mid-upper arm circumference after age adjustment: population-representative surveys from humanitarian settings

et al. 2019

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Background: Mid-upper arm circumference (MUAC) and weight-for-height (WHZ) are commonly used indicators to identify acute malnutrition. However, MUAC and WHZ diagnose different children, and produce prevalence estimates that are meaningfully different. Previous research in Somalia has suggested improved concordance using MUAC-for-age (MUACZ) rather than MUAC. We further evaluate the relationship between MUACZ, MUAC, and WHZ using surveys conducted globally. Methods: We analyzed 882 population representative surveys from 41 countries. Children ages 6-59 months were classified as acutely malnourished using three independent criteria: WHZ < − 2 (WHZ2), MUAC< 125 mm (MUAC125), MUACZ < − 2 (MUACZ2). Population prevalence using each of the three criteria are presented by country and region. Correlations of survey prevalence for each indicator pair were assessed. Multivariable regression models of MUACZ and MUAC125 adjusted for WHZ2, stunting prevalence, age, and sex. To evaluate individual level diagnostic concordance, we compared the proportion of children identified by each of the three criteria. Results: Median prevalence of acute malnutrition overall was highest for MUACZ2 (14.0%) followed by WHZ2 (10.6%), and lowest for MUAC125 (7.3%). The absolute difference in prevalence between MUACZ2 and WHZ2 was smaller than the difference between MUAC125 and WHZ2 for 51.3% of surveys. The correlations of WHZ2 with both MUACZ2 as well as with MUAC125 were weak, positive associations (Pearson's r = 0.5757 and 0.4943, respectively), but MUAC125 and MUACZ2 had a strong, linear relationship (Pearson's r = 0.9265). The adjusted regression model for MUACZ2 had greater fit (R 2 = 0.50) relative to the adjusted model for MUAC125 (R 2 = 0.43). The proportion of children identified by both MUAC125 and WHZ2 was 25.5%, smaller than the proportion identified by both MUACZ2 and WHZ2 (30.6%).

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Section: Discussionmentioning

confidence: 99%

Concordance between estimates of acute malnutrition measured by weight-for-height and by mid-upper arm circumference after age adjustment: population-representative surveys from humanitarian settings

et al. 2019

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“…It has been argued that SAM children presenting with a WHZ < -3 but a MUAC> = 115 mm are relatively healthy, and that SAM children with a low MUAC have a higher risk of death [22,34]. These hypotheses are being challenged by a range of clinical studies [35,36], as well as by direct observation of mortality risks in cohorts of patients [20] and in large community cohorts [3]. It appears that the initially formulated hypothesis that SAM children with low WHZ are at lower mortality risk than low MUAC SAM children was driven by analyses affected by Simpson's paradox, comparing populations of cases not appropriately disaggregated [20].…”

Section: Discussionmentioning

confidence: 99%

“…These hypotheses are being challenged by a range of clinical studies [35,36], as well as by direct observation of mortality risks in cohorts of patients [20] and in large community cohorts [3]. It appears that the initially formulated hypothesis that SAM children with low WHZ are at lower mortality risk than low MUAC SAM children was driven by analyses affected by Simpson's paradox, comparing populations of cases not appropriately disaggregated [20]. The recent evidence suggests that SAM children with low WHZ and those with low MUAC have similar risk of death [3,20].…”

Section: Discussionmentioning

confidence: 99%

“…A recent analysis of more than 1800 crosssectional surveys from 47 countries showed that only 16.5% of SAM children fulfilled both diagnostic criteria (MUAC < 115 mm and WHZ < -3) [19]. Re-analysis of past or modern datasets have also demonstrated that SAM children with low WHZ and SAM children with low MUAC have a similar risk of dying [3,20,21]. These studies also revealed that both deficits have additive effects on mortality risk: SAM children combining a low MUAC and a low WHZ, as well as those combining oedema and low WHZ, have a significantly higher risk of death.…”

Section: Introductionmentioning

confidence: 99%

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Potential consequences of expanded MUAC-only programs on targeting of acutely malnourished children and ready-to-use-therapeutic-food allocation: lessons from cross-sectional surveys

et al. 2020

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Background: Some of the recently piloted innovative approaches for the management of acute malnutrition in children use the "expanded MUAC-only" approach, with Mid Upper Arm Circumference (MUAC) < 125 mm as the sole anthropometric criterion for screening and admission, classification of cases as severe using the 115 mm cutoff, and use Ready-to-Use-Therapeutic-Food (RUTF) for the management of both moderate (MAM) and severe (SAM) cases of acute malnutrition. Our study aimed at exploring the potential consequences of this "expanded MUAC-only" program scenario on the eligibility for treatment and RUTF allocation, as compared with the existing WHO normative guidance. Methods:We analyzed data from 550 population representative cross-sectional cluster surveys conducted since 2007. We retrieved all children classified as SAM and MAM according to currently used case definitions, and calculated the proportions of SAM children who would be excluded from treatment, misclassified as MAM, or whose specific risks (because of having both MUAC and weight-for height deficits) would be ignored. We also analyzed the expected changes in the number and demographics (sex, age) of children meant to receive RUTF according to the new approach.Results: We found that approximately one quarter of SAM children would not be detected and eligible for treatment under the "expanded MUAC-only" scenario, and another 20% would be classified as MAM. A further 17% of the total SAM children would be admitted and followed only according to their MUAC or oedema status, while they also present with a severe weight-for height deficit on admission. Considering MAM targeting, about half of the MAM children would be left undetected. This scenario also shows a 2.5 time increase in the number of children targeted with RUTF, with approximately 70% of MAM and 30% of SAM cases among this new RUTF target.Conclusions: This empirical evidence suggests that adoption of "expanded MUAC-only" programs would likely lead to a priori exclusion from treatment or misclassifying as MAM a large proportion of SAM cases, while redirecting programmatic costs in favor of those less in need. It underscores the need to explore other options for improving the impact of programs addressing the needs of acutely malnourished children.

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“…MAM is currently defined by two criteria: weight‐for‐height z score (WHZ) between −2 and −3 and/or a mid‐upper arm circumference (MUAC) between 115 and 125 mm (WHO, UNICEF, WFP and UNHCR, ). Whether WHZ‐ or MUAC‐based criteria are more suitable for identifying children in need of treatment is still under debate (Briend et al, ; Grellety & Golden, ; Hossain et al, ; Tadesse, Tadesse, Berhane, & Ekström, ), but children falling under each of the categories have not yet been well characterised, including with regard to their motor and language development. The association of linear and ponderal growth with child development has been reported from several low‐ and middle‐income settings (Adair et al, ; Prado et al, ; Worku et al, ).…”

Section: Introductionmentioning

confidence: 99%

Early development in children with moderate acute malnutrition: A cross‐sectional study in Burkina Faso

Olsen

Iuel‐Brockdorff

Yaméogo

et al. 2019

Maternal & Child Nutrition

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Malnutrition impairs cognitive, communication, and motor development, but it is not known how nutrition and health are associated with development in children with moderate acute malnutrition (MAM). We aimed to describe motor and language development of children with MAM and explore its nutrition and health‐related correlates. This cross‐sectional study used baseline data from a nutritional trial in children with MAM aged 6–23 months in Burkina Faso. Motor and language skills were assessed using the Malawi Development Assessment Tool (MDAT). Linear mixed models were used to explore potential correlates of MDAT including socio‐economic status, anthropometry, body composition, whole‐blood polyunsaturated fatty acids (PUFA), haemoglobin (Hb), iron status, and morbidity. We also assessed child and caregiver participation during MDAT procedures and their associations with correlates and development. MDAT data were available for 1.608 children. Mean (95% CI) MDAT z‐scores were −0.39 (−0.45, −0.34) for gross motor, 0.54 (0.48, 0.59) for fine motor, and −0.91 (−0.96, −0.86) for language skills. Children with higher mid‐upper arm circumference, weight‐for‐height, height‐for‐age, fat‐free mass, n‐3 PUFAs, Hb, and iron status had better MDAT z‐scores, whereas children with more fat mass index, anaemia, illness, and inflammation had poorer z‐scores. In addition, children living in larger households or with an unmarried mother had poorer MDAT z‐scores. Associations between morbidity and z‐scores were largely explained by children's poorer participation during MDAT assessment. The identified factors associated with child development may inform interventions needed to stimulate development during or after management of MAM.

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Severely malnourished children with a low weight-for-height have a higher mortality than those with a low mid-upper-arm-circumference: I. Empirical data demonstrates Simpson’s paradox

Cited by 28 publications

References 85 publications

Concordance between estimates of acute malnutrition measured by weight-for-height and by mid-upper arm circumference after age adjustment: population-representative surveys from humanitarian settings

Concordance between estimates of acute malnutrition measured by weight-for-height and by mid-upper arm circumference after age adjustment: population-representative surveys from humanitarian settings

Potential consequences of expanded MUAC-only programs on targeting of acutely malnourished children and ready-to-use-therapeutic-food allocation: lessons from cross-sectional surveys

Early development in children with moderate acute malnutrition: A cross‐sectional study in Burkina Faso

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