Mid-upper arm circumference in detection of weight-for-height Z-score below -3 in children aged 6-59 months

Development and Validation of a Weight Estimation Tool for Acutely Ill Children Who Cannot be Weighed

OBJECTIVES

To develop and validate weight estimation tools using mid upper arm circumference (MUAC) and body length, and determine accuracy and precision of Broselow tape in children 6 mo to 15 y of age.

METHODS

Data of 18,456 children aged 6 mo to 5 y and 1420 children aged 5 to 15 y were used to develop linear regression equations using length and MUAC to estimate weight. These were validated on prospectively enrolled populations of 276 and 312 children, respectively. Accuracy was measured by Bland-Altman bias, median percentage errors, and percentage of predicted weight within 10% of true weight. Broselow tape was tested on the validation population.

RESULTS

Gender specific equations were developed which estimated weight within 10% of true weight in 69.9% (64.1-75.2%) and 65.7% (60.1-70.9%) of children aged 6 mo to 5 y, and 5 to 15 y, respectively. Broselow tape predicted weight within 10% of the true weight in 40.5% (34.7-46.6%) and 32.5% (26.7-38.7%) of children aged 6 mo to 5 y and 5 to 15 y, respectively.

CONCLUSIONS

The model developed from MUAC and length accurately estimated weight in children aged 6 mo to 15 y, and is potentially useful during emergencies. The Broselow tape frequently overestimated weight in authors' setting.

Sensitivity and specificity of mid-upper arm circumference for assessment of severe acute malnutrition among children ages 6 to 59 months: Systematic review and meta-analysis

OBJECTIVES

Sensitivity is the proportion of people classified as diseased (i.e., no false negatives). A test with low sensitivity can be thought of as being too cautious in finding a positive result.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed for this systematic review and meta-analysis. The databases used were PubMed, Google Scholar, Jane, and African Journals Online. The search terms used were "sensitivity" and "specificity of and mid-upper arm circumference" (MUAC). A Joanna Briggs Institute meta-analysis and checklist for diagnostic test accuracy studies was used for the critical appraisal of the studies. The meta-analysis was conducted using STATA, version 14, software. The pooled sensitivity was computed to present the pooled sensitivity at a 95% confidence interval (CI).

RESULTS

A total of 11 individual studies were included in the meta-analysis. The lowest sensitivity of MUAC with the detection of severe acute malnutrition (SAM) was 5% in Vietnam, and the highest sensitivity was at 43.2% in India. The pooled sensitivity of MUAC among children aged <5 y to determine SAM was 20.7% (range, 13.24%-28.25%; P = 0.001). Based on the pooled specificity of MUAC, the detection of SAM was 97.636% (95% CI, 96.339%-98.932%; P = 0.001), and the pooled optimal cutoff point to diagnose SAM was 13.23 cm (95% CI, 12.692-13.763 cm; P = 0.001).

CONCLUSIONS

The sensitivity of MUAC is lower compared with the specificity to detect SAM, and varies from area to area.

Weight-for-height is associated with an overestimation of thinness burden in comparison to BMI-for-age in under-5 populations with high stunting prevalence

BACKGROUND

Thinness at <5 years of age, also known as wasting, is used to assess the nutritional status of populations for programmatic purposes. Thinness may be defined when either weight-for-height or body-mass-index-for-age (BMI-for-age) are below -2 SD of the respective World Health Organization standards. These definitions were compared for quantifying the burden of thinness.

METHODS

Theoretical consequences of ignoring age were evaluated by comparing, at varying height-for-age z-scores, the age- and sex-specific cut-offs of BMI that would define thinness with these two metrics. Thinness prevalence was then compared in simulated populations (short, intermediate and tall) and real-life data sets from research and the National Family Health Survey-4 (NFHS-4) in India.

RESULTS

In short (-2 SD) children, the BMI cut-offs with weight-for-height criteria were higher in comparison to BMI-for-age after 1 year of age but lower at earlier ages. In Indian research and NFHS-4 data sets (short populations), thinness prevalence with weight-for-height was lower from 0.5 to 1 years but higher at subsequent ages. The absolute difference (weight-for-height - BMI-for-age) for 0.5-5 years was 4.6% (15.9-11.3%) and 2.2% (19.2-17.0%), respectively; this attenuated in the 0-5 years age group. The discrepancy was higher in boys and maximal for stunted children, reducing with increasing stature. In simulated data sets from intermediate and tall populations, there were no meaningful differences.

CONCLUSIONS

The two definitions produce cut-offs, and hence estimates of thinness, that differ with the age, sex and height of children. The relative invariance, with age and stature, of the BMI-for-age thinness definition favours its use as the preferred index for programmatic purposes.

Comparison of Mid-Upper-Arm Circumference and Weight-For-Height Z-Score in Identifying Severe Acute Malnutrition among Children Aged 6-59 Months in South Gondar Zone, Ethiopia

Children with severe acute malnutrition (SAM) are identified for admission to outpatient therapeutic programs using mid-upper-arm circumference (MUAC) or weight for height (WHZ). However, MUAC and WHZ do not identify the same children, and such observed differences might have programmatic implications of missed nutrition therapy if only MUAC is used to identify children with SAM. The objective of the study was to assess any difference in prevalence and degree of agreement between MUAC and WHZ in identifying SAM affected children. A cross-sectional study was conducted in South Gondar Zone, Ethiopia, among 17 districts, with 3 districts and 10 health centers with their clustered health posts selected randomly. A total of 2,040 children were recruited, and data were collected using a parent questionnaire then entered into EpiData and analyzed using SPSS v 20. A total of 1,980 respondents (97.1%) were interviewed, all of whom were female and rural residents. Children's mean age in months was 23.2 (SD ± 9.7), and 54% were male children. The prevalence of SAM based on MUAC <11.5 cm was 11.2% (95% CI: 9.9–12.7) and 11.0% (95% CI: 9.7–12.5) based on WHZ <−3. The agreement between MUAC and WHZ was good (k = 0.729). The proportion of children with SAM identified using both MUAC and WHZ was 61.2%. The prevalence of SAM identified using both MUAC and WHZ was comparable. A substantial degree of agreement between MUAC and WHZ was observed to diagnose SAM. Therefore, MUAC can be used as an appropriate tool in identifying children with SAM for admission into the outpatient therapeutic program (OTP) in the study area.

Mortality and recovery following moderate and severe acute malnutrition in children aged 6-18 months in rural Jharkhand and Odisha, eastern India: A cohort study

BACKGROUND

Recent data suggest that case fatality from severe acute malnutrition (SAM) in India may be lower than the 10%-20% estimated by the World Health Organization (WHO). A contemporary quantification of mortality and recovery from acute malnutrition in Indian community settings is essential to inform policy regarding the benefits of scaling up prevention and treatment programmes.

METHODS AND FINDINGS

We conducted a cohort study using data collected during a recently completed cluster-randomised controlled trial in 120 geographical clusters with a total population of 121,531 in rural Jharkhand and Odisha, eastern India. Children born between October 1, 2013, and February 10, 2015, and alive at 6 months of age were followed up at 9, 12, and 18 months. We measured the children's anthropometry and asked caregivers whether children had been referred to services for malnutrition in the past 3 months. We determined the incidence and prevalence of moderate acute malnutrition (MAM) and SAM, as well as mortality and recovery at each follow-up. We then used Cox-proportional models to estimate mortality hazard ratios (HRs) for MAM and SAM. In total, 2,869 children were eligible for follow-up at 6 months of age. We knew the vital status of 93% of children (2,669/2,869) at 18 months. There were 2,704 children-years of follow-up time. The incidence of MAM by weight-for-length z score (WLZ) and/or mid-upper arm circumference (MUAC) was 406 (1,098/2,704) per 1,000 children-years. The incidence of SAM by WLZ, MUAC, or oedema was 190 (513/2,704) per 1,000 children-years. There were 36 deaths: 12 among children with MAM and six among children with SAM. Case fatality rates were 1.1% (12/1,098) for MAM and 1.2% (6/513) for SAM. In total, 99% of all children with SAM at 6 months of age (227/230) were alive 3 months later, 40% (92/230) were still SAM, and 18% (41/230) had recovered (WLZ ≥ -2 standard deviation [SD]; MUAC ≥ 12.5; no oedema). The adjusted HRs using all anthropometric indicators were 1.43 (95% CI 0.53-3.87, p = 0.480) for MAM and 2.56 (95% CI 0.99-6.70, p = 0.052) for SAM. Both WLZ < -3 and MUAC ≥ 11.5 and < 12.5 were associated with increased mortality risk (HR: 3.33, 95% CI 1.23-8.99, p = 0.018 and HR: 3.87, 95% CI 1.63-9.18, p = 0.002, respectively). A key limitation of our analysis was missing WLZ or MUAC data at all time points for 2.5% of children, including for two of the 36 children who died.

CONCLUSIONS

In rural eastern India, the incidence of acute malnutrition among children older than 6 months was high, but case fatality following SAM was 1.2%, much lower than the 10%-20% estimated by WHO. Case fatality rates below 6% have now been recorded in three other Indian studies. Community treatment using ready-to-use therapeutic food may not avert a substantial number of SAM-related deaths in children aged over 6 months, as mortality in this group is lower than expected. Our findings strengthen the case for prioritising prevention through known health, nutrition, and multisectoral interventions in the first 1,000 days of life, while ensuring access to treatment when prevention fails.

Severely malnourished children with a low weight-for-height have a higher mortality than those with a low mid-upper-arm-circumference: III. Effect of case-load on malnutrition related mortality- policy implications

BACKGROUND

Severe acute malnutrition (SAM) is diagnosed when the weight-for-height Z-score (WHZ) is <-3Z of the WHO2006 standards, or a mid-upper-arm circumference (MUAC) of < 115 mm or there is nutritional oedema. Although there has been a move to eliminate WHZ as a diagnostic criterion we have shown that children with a low WHZ have at least as high a mortality risk as those with a low MUAC. Here we take the estimated case fatality rates and published case-loads to estimate the proportion of total SAM related deaths occurring in children that would be excluded from treatment with a MUAC-only policy.

METHODS

The effect of varying case-load and mortality rates on the proportion of all deaths that would occur in admitted children was examined. We used the same calculations to estimate the proportion of all SAM-related deaths that would be excluded with a MUAC-only policy in 48 countries with very different relative case loads for SAM by only MUAC, only WHZ and children with both deficits. The case fatality rates (CFR) are taken from simulations, empirical data and the literature.

RESULTS

The relative number of cases of SAM by MUAC alone, WHZ alone and those with both criteria have a dominant effect on the proportion of all SAM-related deaths that would occur in children excluded from treatment by a MUAC-only program. Many countries, particularly in the Sahel, West Africa and South East Asia would fail to identify the majority of SAM-related deaths if a MUAC only program were to be implemented. Globally, the estimated minimum number of deaths that would occur among children excluded from treatment in our analyses is 300,000 annually.

CONCLUSIONS

The number, proportion or attributable fraction of children excluded from treatment with any change of current policy are the correct indicators to guide policy change. CRFs alone should not be used to guide policy in choosing whether or not to drop WHZ as a diagnostic for SAM. All the criteria for diagnosis of malnutrition need to be retained. It is critical that methods are found to identify those children with a low WHZ, but not a low MUAC, in the community so that they will not remain undetected.