Accuracy of Using Mid-Upper Arm Circumference to Detect Wasting Among Children Aged 6–59 Months in Nepal

Diagnostic accuracy of MUAC for assessment of acute malnutrition among children aged 6-59 months in Africa: systematic review and meta-analysis

Background

Mid-Upper Arm Circumference (MUAC) or Weight-for-Length Z-Score (WHZ) are used to screen for acute malnutrition in children. The relative merits of MUAC and WHZ, as well as whether they ought to be used separately, are still up for debate. Considering the significant impact of acute malnutrition on a large number of children in Africa, along with the constraints on resources, it is crucial to critically assess the validity of simple and widely used tools utilized in both African communities and clinical settings. Therefore, this study aimed to assess the diagnostic test accuracy of MUAC in screening acute malnutrition among children aged 6-59 months in Africa.

Methods

A systematic review and meta-analysis study was conducted to pool evidence on the diagnostic performance of MUAC compared to WHZ among children aged 6 to 59 months across various studies in Africa. The StataMP 17.0 software was utilized for analysis, employing a Bivariate Random-effects Meta-Analysis model. Sensitivity, specificity, the Diagnostic Odds Ratio, and the Area Under the Curve were calculated. Heterogeneity was assessed using Cochrane's Q statistic and the I2 test. Additionally, meta-regression, subgroup analysis, sensitivity analysis, and assessments for publication bias were employed. The overall level of diagnostic test accuracy was estimated using a random-effects meta-analysis model.

Results

Seventeen studies were included in the meta-analysis. The pooled sensitivity and specificity were 38.1% (95% CI: 30.7, 46.1%) and 94.9% (95% CI: 93.2, 96.2%), respectively. The summary receiver operating characteristic curve plot showed that MUAC had good accuracy in detecting acute malnutrition (AUC = 0.85, 95% CI: 0.82, 0.88). The pooled level of diagnostic odds ratio was 13.22 (95% CI: 9.68, 16.77). The rate of misclassification in screening for acute malnutrition using MUAC was observed to be 11.7%.

Conclusion

The MUAC demonstrated low sensitivity but high specificity in diagnosing acute malnutrition in children aged 6 to 59 months across various regions of Africa. Furthermore, it was found that MUAC provides good diagnostic test accuracy when compared to WHZ. To enhance its accuracy, it is suggested to increase the MUAC cutoff thresholds.

Determining an optimal case definition using mid-upper arm circumference with or without weight for age to identify childhood wasting in the Philippines

In resource-limited areas, where accurate weight-for-height Z-scores are hard to obtain, Mid-Upper Arm Circumference (MUAC) is a simple tool to identify wasted children. MUAC alone, however, may miss identification of many wasted children, leading to untimely intervention and potentially death. Our study aimed to identify the best-performing case definition to detect wasting by Weight-for-Height z-scores (WHZ) in Filipino children aged 6-59 months. We analyzed the 2018-2019 Expanded National Nutrition Survey to assess the diagnostic performance of MUAC cutoffs and a case definition combining MUAC and weight-for-age z-score (WAZ) in identifying moderate and severe wasting compared to the WHZ criterion. The optimal cutoff and case definition was identified as having the highest area under the receiver operating characteristic curve (AUROC). Our findings showed that the current MUAC cutoffs poorly identify severe (sensitivity: 13%; specificity: 99%; AUROC: 0.558) and moderate (sensitivity: 22%; specificity: 96%; AUROC: 0.586) wasting (N = 30,522) in Filipino children. Instead, the optimal MUAC cutoff for severe and moderate wasting were <13.6cm (sensitivity: 62%; specificity: 76%; AUROC: 0.690) and 14.0cm (sensitivity: 80%; specificity: 67%; AUROC: 0.737). There was no effect of sex on MUAC cutoffs, but cutoffs increased with age. We found that the combination of WAZ < -2 or MUAC ≤ 11.7cm (Sensitivity: 80%; Specificity: 80%; AUROC: 0.800) for severe wasting and WAZ < -2 or MUAC ≤ 12.7cm (Sensitivity: 84%; Specificity: 78%; AUROC: 0.810) for moderate wasting significantly improved sensitivity for acceptable decreases in specificity. In summary, implementing alternative case definitions solely based on expanding MUAC insufficiently improves diagnostic accuracy for identifying wasted children by WHZ criteria. Combining WAZ with MUAC could increase the number of eligible children identified and treated by the Philippine Integrated Management of Acute Malnutrition. Further studies are advised to understand the practicality and cost-effectiveness of using the proposed alternative case definitions in the Philippines.

Utility of mid-upper arm circumference in pediatric malnutrition: An Australasian Society of Parenteral and Enteral Nutrition consensus statement using the Delphi method

BACKGROUND

Mid-upper arm circumference (MUAC) is a simple anthropometric tool used to screen for childhood undernutrition in humanitarian settings or low-income and middle-income countries. However, there is conflicting evidence and a lack of consensus with regard to its diagnostic use in clinical settings or population groups beyond this context. In 2023, a project officer was appointed by the Australasian Society of Parenteral and Enteral Nutrition (AuSPEN) to lead the development of a consensus review into the use of MUAC in the pediatric clinical setting.

METHODS

An AuSPEN appointed multidisciplinary group of informed clinicians used the Delphi method to critically appraise the evidence and develop a series of consensus statements. Delphi surveys were anonymous and distributed electronically. Members were asked to rate their level of agreement with each consensus statement using a 5-point Likert scale. A priori definition of consensus was established as ≥80% responses "agree" or "strongly agree."

RESULTS

Three Delphi rounds were required to reach consensus. A total of 18 consensus statements, including rationale, were developed across the topics 'assessment and diagnosis', 'screening and monitoring' and 'clinical settings'.

CONCLUSION

An evidence-based, region-specific consensus approach to the use of MUAC in pediatric malnutrition is a valuable tool for clinicians. MUAC is a straightforward, non-invasive and cost-effective tool, and may provide an advantage over traditional anthropometric tools in some clinical settings. There are limitations to the utility of MUAC and this consensus paper provides an empirical summary of advantages and limitations as they apply to the screening, assessment, diagnosis, and monitoring of pediatric malnutrition.

Improving case-detection of severe wasting among under-five-year-old children in Timor Leste: A secondary analysis of data from the 2020 national cross-sectional food and nutrition survey

The World Health Organization recommends using weight-for-height Z-score (WHZ) <-3 or Mid-Upper Arm Circumference (MUAC) <115 mm as independent criteria for diagnosing severe wasting. However, there are several challenges in using the WHZ criterion. As a result, the MUAC (and edema)-only approach for identifying children needing treatment for severe wasting has been developed and is being rapidly scaled-up globally, including in Timor-Leste. But previous studies reported that MUAC<115 mm has poor diagnostic accuracy for detecting children with WHZ<-3. The two options being explored globally for improving the identification of these children in MUAC (and edema)-only programming contexts include expanding MUAC cut-off and the combination of the indicators MUAC and Weight-for-Age Z-score (WAZ). This study explored the accuracy for diagnosing severe wasting (WHZ<-3) of these two options in Timor-Leste. We conducted a secondary analysis of data from the 2020 national Timor-Leste Food and Nutrition Survey. We tested the accuracy of various MUAC cut-offs, and predefined case definitions in five age groups (0-5 months, 6-23 months, 24-59 months, 6-59 months, and 0-59 months). We calculated the standard diagnostic test parameters (sensitivity, specificity, Youden Index, and others) and used the Youden Index as the principal criterion for rating the overall level of accuracy. The sample analyzed comprised 11,056 children with complete information on our key variables (anthropometric data, age, and sex), of whom 52.2% were boys. The age groups 0 to 5 months, 6 to 23 months, and 24 to 59 months represented 9.0%, 33.7%, and 57.3% of the sample, respectively. We found that the optimal diagnostic MUAC cut-off varied across the age groups between 117 mm and 142 mm, with the Youden Index remaining < 55% in all the age groups considered. The use of case definitions combing MUAC and WAZ optimized the identification of children with WHZ<-3. The case definition MUAC<130 mm or WAZ<-3 Z-score had the best diagnostic accuracy in all the age groups except for the 0 to 5 months age group for which the case definition MUAC<110 mm or WAZ<-2 Z-score had the highest Youden Index. Our findings show that it is challenging to significantly improve diagnostic accuracy for identifying children with WHZ<-3 by only expanding the MUAC cut-off in under five Timorese children. However, In settings facing challenges in using WHZ, the combination of MUAC and WAZ indicators offers a promising approach. Further research is needed to confirm the effectiveness of the proposed combination of MUAC and WAZ indicators case definitions in a programmatic context in Timor-Leste, and other similar contexts.

Three-arm clinical trial of improved flour targeting intestinal microbiota (MALINEA)

The main objective of this project was to compare in the field conditions two strategies of re-nutrition of children with moderate acute malnutrition (MAM) aged from 6 to 24 months, targeting the microbiota in comparison with a standard regimen. A three-arm, open-label, pragmatic randomised trial was conducted in four countries (Niger, CAR, Senegal and Madagascar). Children received for 12 weeks either fortified blended flour (FBF control) = arm 1, or FBF + azithromycin (oral suspension of 20 mg/kg/day daily given with a syringe) for the first 3 days at inclusion = arm 2 or mix FBF with inulin/fructo-oligosaccharides (6 g/day if age ≥12 months and 4 g if age <12 months) = arm 3. For each arm, children aged from 6 to 11 months received 100 g x 2 per day of flours and those aged from 12 to 24 months received 100 g × 3 per day of FBF. The primary endpoint was nutritional recovery, defined by reaching a weight-for-height z-score (WHZ) ≥ -1.5 within 12 weeks. Overall, 881 children were randomised (297, 290 and 294 in arm 1, arm 2 and arm 3, respectively). Three hundred and forty-four children were males (39%) and median/mean age were 14.6/14.4 months (SD = 4.9, IQR = 10.5-18.4). At inclusion, the three arms were comparable for all criteria, but differences were observed between countries. Overall, 44% (390/881) of the children recovered at week 12 from MAM, with no significant difference between the three arms (41.4%, 45.5% and 45.9%, in arm 1, arm 2 and arm 3, respectively, p = 0.47). This study did not support the true advantages of adding a prebiotic or antibiotic to flour. When using a threshold of WHZ ≥ -2 as an exploratory endpoint, significant differences were observed between the three arms, with higher success rates in arms with antibiotics or prebiotics compared to the control arm (66.9%, 66.0% and 55.2%, respectively, p = 0.005).

Diagnostic Accuracy of Mid-Upper Arm Circumference for the Detection of Acute Malnutrition Among Children Aged 6-60 Months: A Diagnostic Accuracy Study

BACKGROUND

Timely and accurate screening of malnutrition at the community level is essential to identifying malnourished children. The World Health Organization (WHO) guidelines classify non-oedematous acute malnutrition among children using mid-upper arm circumference (MUAC) or weight-for-height Z-score (WHZ). Study Design: A cross-sectional study.

METHODS

This study was conducted among children aged 6‒60 months. After necessary exclusions, 433 participants were selected using a multi-stage simple random sampling method. Using WHO guidelines for global acute malnutrition (GAM) [WHZ<-2, MUAC<12.5 cm], the sensitivity (Se), specificity (Sp), predictive values, likelihood ratios, Youden index, and receiver operating characteristic (ROC) curve were calculated for MUAC using WHZ as the criterion.

RESULTS

Out of 433 participants, 30% were diagnosed with GAM using WHZ, while 17.6% were found malnourished using MUAC measurements. As per WHO cut-offs, the Se, Sp, positive predictive value (PPV), negative predictive value (NPV), Youden index, positive likelihood ratio (LR+), and negative likelihood ratio (LR-) of MUAC were 48%, 96%, 83%, 81%, 0.44, 12, and 0.54, respectively. The ROC curve displayed an area under the curve of 0.86 (95% confidence interval=0.83, 0.90) for MUAC<12.5 cm. Bivariate Pearson correlation also demonstrated a positive linear relationship (R2=0.302) between the WHZ and MUAC variables.

CONCLUSION

Based on the findings, 48% of the children were correctly identified by the MUAC with an 83% probability of GAM (PPV=0.83). Moreover, there was 96% Sp in non-malnourished children, with only 4% false positives. Therefore, personnel at the grassroots level can use MUAC for timely and accurate screening of children in Anganwadi centers (AWCs) due to its ease of use and simplicity.

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.

Accuracy of Mid-Upper Arm Circumference for Detecting Acute Malnutrition in Children Aged 6-59 Months in an Urban Slum in Bangladesh: A Cross-Sectional Analysis

Background The weight-for-height z-score (WHZ) is considered the gold standard for detecting acute malnutrition in children. However, an accurate assessment of WHZ can often be challenging, especially in community settings. Mid-upper arm circumference (MUAC) is a simple and easy-to-perform method to identify children with acute malnutrition. The objective of the study was to evaluate the accuracy of MUAC in detecting acute malnutrition compared to WHZ among children aged 6-59 months in Bangladesh. Methods We used anthropometric data for 239 children aged 6-59 months from a cross-sectional study conducted in 2013 in an urban slum in Dhaka, Bangladesh. The sensitivity and specificity of MUAC to detect acute malnutrition were calculated, considering WHZ as the gold standard. Results The mean age of the children was 29.4 ± 12.7 months, with a male-to-female ratio of 1:1.2. The prevalence of acute malnutrition was 17.1% and 22.5% based on WHZ and MUAC, respectively. The total area under the receiver operating characteristic curve was 0.816. For detecting acute malnutrition, the sensitivity of MUAC was 61.0% and the specificity was 85.4% for the World Health Organization (WHO) recommended cutoff of <125 mm. Using the Youden index, the best MUAC cutoff point to detect acute malnutrition was <128 mm with a sensitivity of 75.6% and a specificity of 74.7%. Conclusions Our study demonstrated a low sensitivity of MUAC to identify acute malnutrition at the WHO cutoff of <125 mm. The cutoff could be increased to <128 mm to capture more children with acute malnutrition.

Utilization of mid-upper arm circumference as discharge tool for children in outpatient therapeutic program, Ethiopia

Mid-upper arm circumference (MUAC) is simple to use and inexpensive in Ethiopia; both MUAC and target weight are employed, although the time to cure for MUAC is not indicated. The present study is aimed to determine cure time of MUAC for children in outpatient therapeutic program. A prospective cohort study was conducted among 414 severe acute malnourished under-five children admitted to selected health twenty-two posts from 1 February to 30 July 2021, in Oromia, Ethiopia. Data were coded, entered to Ep-data version 4.2 software, and transferred to SPSS for windows version 25 software for analysis. The Multivariate Cox Proportional Hazards model was used to fit independent determinants of time to cure. All tests were two-sided and statistical implications at P-values < 0⋅05. In the present study, the minimum week for a cure was 4 weeks, the maximum was 16 weeks and the overall time to cure severe acute malnutrition as measured by MUAC is judged to be 10 at 95 % CI (9⋅65-10⋅35). Families with six or more members are 2⋅16 times more at risk, children from homes with the lowest wealth index are at 1⋅4 times more risk, and children from food insecure families were 2⋅61 times more likely to require long-term treatment for MUAC. In the present study, the time to cure severe acute malnutrition by MUAC is determined as 10 weeks. Moreover, family size, low wealth index, and household food insecurity were risks to delay in cure time MUAC.

Validating the diagnostic performance of MUAC in screening moderate acute malnutrition and developing an optimal cut-off for under five children of different regions in Ethiopia

Background

Valid and reliable anthropometric indicator is useful for early detection and treatment for under nutrition. Although, mid upper arm circumference (MUAC) is used for screening of children with moderate acute malnutrition in Ethiopia, its performance for the different ethnic groups has not been evaluated.

Objective

To determine the diagnostic performance of MUAC for determination of moderate wasting among children of different ethnic background and develop optimal cut-off.

Methods

A community based cross-sectional study was conducted among under five children of the three regions namely: Somalia, Amhara and Gambella Regions. The diagnostic performance of MUAC was validated using weight for height Z-score< -2 as a gold standard binary classifier. Test variable is mid upper arm circumference (MUAC< 12.5cm) and weight for height Z-Score (WHZ) is standard variable. ROC analysis performed based on the assumptions of MUAC value lower the cut-off point indicates the undernutrition. Area under the curve and validity measures (sensitivity and specificity) was generated as parameter estimated. The results were presented using tables and ROC curves.

Results

Except in the Gambella region, there was fair agreement between MUC<12.5cm and Weight for Height Z score<-2 in diagnosing wasting in Somali (Sensitivity = 29.3%, Kappa = 0.325, P<0.001) and in Gambella regions (Sensitivity = 16.7%, Kappa = 0.19, P<0.001). In Amhara region there was fair agreement between the two measures in diagnosing moderate acute malnutrition (MAM) (Sensitivity = 16%, Kappa = 0.216). For the Overall sample, the sensitivity of MUAC<12.5cm was 20.6% (Kappa = 0.245, P<0.001. Based on ROC analysis, the optimal cutoff value of MUAC for diagnosing moderate acute malnutrition for the two regions namely for Gambella and Amhara was 13.85cm with sensitivity of 0.99 and 1.00, respectively. However, for Somali Region the optimal cut was 13.75cm (Sensitivity = 0.98 cm and specificity = 0.71).

Conclusion

Findings revealed that the inter reliability of measurement for MUAC< 12.5cm and WHZ<-2 for diagnosing MAM was low among different ethnic groups with the cut-off varying in each region. The existing cutoff point is less sensitive for diagnosis of MAM. As Ethiopia is home of diverse ethnic groups with different body frame and environmental conditions, the new cut off points developed for each region recommended to be used for screening moderate acute malnutrition to prevent relapse of MAM and reduce chronic malnutrition.