Factors associated with nutritional status improvement in hospitalized oldest-old adults at nutritional risk

Malnutrition is highly prevalent among hospitalized older adults and is associated with adverse clinical outcomes. However, the determinants of nutritional improvement and clinical implications of such improvement in oldest-old hospitalized patients remain insufficiently characterized. This study aimed to identify factors associated with nutritional improvement and to evaluate the relationship between this improvement and clinical outcomes among hospitalized patients aged ≥80 years who were at nutritional risk.

This multicenter prospective cohort study included hospitalized patients aged ≥ 80 years at nutritional risk (Nutritional Risk Screening 2002 score ≥ 3) from geriatric wards of tertiary hospitals in China. Nutritional status was assessed using the Mini Nutritional Assessment-Short Form (MNA-SF) at admission and at 90-day follow-up. Nutritional improvement was defined as an improvement in MNA-SF category at 90 days. Multivariable logistic regression analyses were performed to identify factors associated with nutritional improvement and to examine the association between nutritional improvement and adverse clinical outcomes, including mortality, readmission, falls, and infection.

Among 675 patients included in the final analysis (mean age 88.5 ± 4.8 years; 63.7% male), 251 (37.2%) achieved nutritional improvement at 90 days. In multivariable analyses, a higher Charlson Comorbidity Index was associated with a lower likelihood of nutritional improvement (odds ratio [OR] = 0.751, 95% confidence interval [CI]: 0.665-0.849, p < 0.001). Achieving energy adequacy (OR = 2.424, 95% CI: 1.511-3.887, p < 0.001) and good adherence to nutritional interventions (OR = 1.921, 95% CI: 1.303-2.834, p < 0.001) were independently associated with nutritional improvement, whereas protein adequacy was not. Nutritional improvement was independently associated with reduced risks of readmission (OR = 0.545, 95% CI: 0.351-0.847, p = 0.007) and new infection (OR = 0.388, 95% CI: 0.225-0.671, p < 0.001) but was not significantly associated with mortality or falls.

Among hospitalized oldest-old patients at nutritional risk, achieving adequate energy intake and maintaining adherence to nutritional interventions were independently associated with nutritional improvement. Nutritional improvement was associated with lower risks of readmission and infection. These findings highlight the potential clinical relevance of sustained nutritional monitoring and management in oldest-old hospitalized populations.