Global observational analysis of the Quality of Care Index (QCI) for protein-energy malnutrition from 1990 to 2021

Protein-energy malnutrition (PEM) remains a critical global health challenge, and the quality of care for PEM remains a key focus in the current public health field. Systematically evaluating these disparities is essential for guiding public health policy. This study adopted a revised Quality of Care Index (QCI) to evaluate global PEM care performance from 1990 to 2021. This study is based on data from the Global Burden of Disease (GBD) 1990 to 2021. The 4 secondary indicators were integrated through principal component analysis (PCA) to construct the QCI. The machine learning interpretability tool SHAP (SHapley Additive exPlanations) was utilized to deeply analyze the key factors affecting the QCI. The Bayesian age-period-cohort (BAPC) model was employed to predict the QCI trends from 2022 to 2033. From 1990 to 2021, while PEM incidence and prevalence counts increased, age-standardized rates of prevalence, incidence, mortality, and disability-adjusted life years (DALYs) declined. The QCI revealed substantial geographical disparities, strongly correlated with the Socio-Demographic Index (SDI). High-income regions, notably Northern Europe, achieved the highest QCI scores, while low-income regions, such as parts of West Africa and Southeast Asia, recorded the lowest. The QCI followed a U-shaped curve across the lifespan, being highest in children under 5, lowest in adolescents (10–14 years), and rising again in older adulthood. Sex-based differences were minimal. SHAP analysis confirmed SDI, age, and time as major QCI determinants. Projections suggest a continued, albeit slow, global improvement in the QCI. The QCI serves as a robust composite metric for benchmarking PEM care. Our findings highlight that the quality of PEM care is inextricably linked to socioeconomic development and underscore the need for targeted interventions aimed at vulnerable age groups and underserved regions to mitigate disparities and elevate global care standards.