Evaluating the Diagnostic Accuracy of CANS, Anthropometric, and Proportionality Indices for Fetal Malnutrition in Pakistan

Background: Fetal Malnutrition (FM), a serious neonatal condition, is characterized by inadequate accumulation of subcutaneous fat and muscle, independent of birth weight for gestational age. This study aims to assess and compare the diagnostic accuracy of various nutritional assessment methods, including the Clinical Assessment of Nutritional Status (CANS) score, anthropometric measurements, and proportionality indices in identifying FM. Methodology: This cross-sectional study included 320 live singleton newborns at Sheikh Khalifa Bin Zayed Al Nahyan Hospital, Rawalakot, Azad Kashmir, Pakistan, from December 2022 to July 2023. The neonatal participants were comprehensively assessed in terms of the CANS score, anthropometric measurements (weight, length, and Body Mass Index_(BMI)), and proportionality indices such as the Ponderal Index (PI) and the Mid-Upper Arm Circumference to Head Circumference ratio (MUAC/HC). Diagnostic accuracy metrics (sensitivity, specificity, Positive Predictive Value [PPV], and Negative Predictive Value [NPV]) were calculated according to established FM diagnostic criteria. Results: Among the 320 neonates considered in this study, 61.3% were male, and 25.6% were preterm. The mean birth weight was 2.61 ± 0.73 kg, with a mean CANS score of 25.06 ± 8.21. A significant association was observed between gestational age and nutritional status. Preterm neonates exhibited higher rates of FM, as measured by MUAC/HC, PI, and BMI (p < 0.001). Diagnostic accuracy assessments indicated that when the CANS score is considered a gold standard, it demonstrated perfect sensitivity and specificity for detecting FM, while BMI and PI showed lower but significant sensitivity and specificity. The combination of BMI and PI (among metrics excluding the CANS score) yielded the highest accuracy in FM detection, reducing diagnostic errors significantly. Conclusions: FM prevalence was substantial in the studied population sample, particularly among preterm neonates. The CANS score remains a robust tool for FM detection and its incorporation with BMI and PI further enhances diagnostic accuracy. These findings highlight the importance of precise FM assessment and early optimization of neonatal nutritional intake to mitigate the detrimental sequalae of malnutrition.