A total of 313 complicated severely wasted children (cases) were admitted to the TFC, boys (48.9%) and girls (51.1%). Uncomplicated severely wasted children (controls) admitted to the OTP were 122, among them boys (41.8%) and girls (58.2%).

Mean age, weight, length/height, and MUAC among the cases were (13.04±7.34 mo., 5.41±1.33 kg, 68.32±7.10 cm, and 10.57±1.36 cm) respectively; while the mean age, weight, length/height, and MUAC among the controls were (20.05±12.93 mo., 7.05±1.74 kg, 76.89±10.46 cm, and MUAC 11.28±1.11 cm) respectively. P value <0.001 presented in Table 1.

Figure 1 shows that severe wasting by WFL/H < - 3SD z-score group of severity seen more among the control; cases vs controls were (37.0% vs 68.9%). Howevere, the other groups of severity of WFL/H z-score below the cut off of – 3SD z-score seen more among the cases compared to the controls with nearly douple frequencies as follow: (35.8% vs 18.8% < - 4SD), (14.7 vs 7.4% < - 5SD). Less than – 6SD group of severity was seen much more among the cases vs the controls (8.6% vs 1.6%). Less than – 7 SD among the cases was 1.3% and no children belong to this group in the controls. Those study children with < - 2 SD (moderate wasting by WFL/H) were admitted for severe wasting by MUAC criterion of < 11.5 cm.

Table 2 shows that out of the total complicated severely wasted children admitted by WFL/H < - 3 SD, 59.1% belong to 6-12 mo. age group and children aged 6-24 months represented 93.3%.

Only 4.2% of children belong the age group 25-60 mo. Among the controls, the proportion of children from the three age groups were nearly similar, with 6-12 mo., 13-24 mo, and 25-60 mo. represented 34.4%, 35.2%, and 27.1% respectively. Severe stunting was found among 41.9% of the cases and nearly all belong to the age group 6-24 mo. while severe stunting was seen among 16,4% of the controls and nearly similar proportion in the three age groups. MUAC < 11.5 cm among the cases was 46.0%, 20.4%, and 1.3% in the three age groups respectively, while among the controls was 24.6%, 13.1%, and 11.5% in the three age groups respectively. A statistically significant age group difference between the cases and the controls, p-value is < 0.001.

In the present case control study, complicated severely wasted children admitted to inpatient care were younger, had significantly low mean weight, height, and MUAC compared to uncomplicated severely wasted children admitted to outpatient care.

It was observed that WFL/H <- 3SD z-score group of severity seen more among the control; cases vs controls were (37.0% vs 68.9%). Howevere, comparing the other groups of severity (< - 4SD, < - 5SD, and < - 6SD z-scores), it was found that the proportion of these groups of severity among the cases were nearly more than twice the proportion in the controls. In addition, there were no children in control group with WFL/H <- 7SD z-score. A similar hospital based case control study was done in Rajasthan, India showed that < - 3SD z-score among the cases vs the controls was (26.0% vs 32.0%), < - 4SD cases vs controls was (27.0% vs 28.0%), and the proportion of < - 5 SD and < - 6SD group of severity was high among the cases vs the controls. No children among the controls belong to the groups < - 7SD and < - 8SD 7. These findings support the evidence that children with SAM who develop complications have severe deterioration of nutritional anthropometric indices compared to those admitted to outpatient care 8.

In our TFP, the majority of children admitted for severe wasting by WFL/H < - 3SD z-score criterion, not by MUAC criterion, and nearly similar proportion was found in the TFC and OTP (97.5%) and (96.7%) respectively. Similar finding was seen in a multicounty study done in India where the proportion of total children diagnosed as SAM by WFL/H z-score were significantly high (84.5%), compared to MUAC criterion 9.

MUAC < -11.5 cm was simultaneously found among (67.7%) of the cases that were identified as severe wasting by WFL/H, compared to (49.2%) among the controls. However, only (2.6%) and (3.3%) of children were admitted for severe wasting by only MUAC < 11.5 cm criterion in the cases and controls, respectively. If < 11.5 cm MUAC is used as a stand alone criterion in our TFP, then a large number of severely wasted children will remain undetected. MUAC becomes an essential tool, as it is a quick, easy and cheap method to identify acutely malnourished children in low-income, high-prevalence or emergency settings where resources may be limited. In addition, MUAC is primarily used to produce rapid prevalence estimates, and for community screening via Community-based Management of Acute Malnutrition (CMAM). Moreover, global evidence suggests that MUAC identifies children who are at a higher risk of mortality and require immediate care 10. However, in spite of MUAC s higher functionally as an alternative in areas of scarce resources or as mortality predictor, it s diagnostic value continues to be debated 11.

Significant proportion of cases were also stunted compared to the controls (41.9% vs 16.4%) and the majority of the cases were 6-24 mo. age group compared to the control (39.3% vs 11.5%).

The proportion of stunting among our cases was higher than the proportion among complicated SAM found in a hospital based studies done in Egypt and Western Kenya, 23.2% and 23.0%, respectively 1213, and is much higher than stunting among 6-24 month old children in a study included hospitalized children in Nepal (4.7%) 14. In the Yemeni context, malnutrition in this age group mostly related to improper complementary feeding practice. According to SMART surveys conducted in 2021, only one in 10 children aged 6-23 months in Yemen receives an adequate diet in the complementary feeding period, with only 12% receiving a minimum acceptable diet. High levels of poverty, spiraling food prices, poor access to services, and the constraints on the daily lives of women, such as movement restriction and challenges accessing financial services, all present challenges to following recommended complementary feeding practices. A lack of knowledge on age-appropriate behaviours and a lack of interaction with children during meals have also been highlighted as barriers to appropriate practice 14.