Optimizing Nutritional Outcomes in Residential Care: The Critical Role of Caregiver Training Frequency and Caregiving Competency

Background: Malnutrition is highly prevalent among institutionalized older adults. As key care providers, caregivers' training quality affects nutritional outcomes. This study aims to guide policymakers by examining the relevant mechanisms and group differences. Methods: Using matched data of 1,656 institutionalized older adults and 339 caregivers from the NISAS, HLM was conducted to examine how caregiver training impacts residents' nutritional status. Robustness was tested using OLS regression, variable replacement, and multiple imputation. We further investigated the mediating effect of caregiving competency and heterogeneity across caregiver work experience, resident gender, and age groups. Results: Nearly half of older adults in institutions were malnourished or at risk of malnutrition, with advanced age and the female population being particularly vulnerable. Caregiver training frequency demonstrated a significant positive effect on residents' nutritional status. Caregiving competency partially mediated this relationship, with training frequency significantly improving competency, thereby enhancing nutritional outcomes. The effectiveness of training exhibited group heterogeneity. Training effects were significantly stronger among caregivers with longer work experience but attenuated in the oldest-old residents. Female residents benefited slightly less than males, and the oldest-old females exhibited a cumulative disadvantage, experiencing the most pronounced attenuation in the training effect. Conclusions: This study contributes to advancing the understanding of caregiving relationships within institutions and provides empirical evidence for optimizing institutional care policies. Increasing caregiver training frequency improves nutritional outcomes, with differential effects across subgroups necessitating tailored training protocols and strengthened nutritional assessment modules.