Malnutrition as a major related factor of frailty among older adults residing in long-term care facilities in Korea

**Background:** Frailty is a major problem in older populations, defined as reduced reserve capacity to resist stressors, leading to falls, disability, hospitalization, and death. The prevalence of frailty in long-term care facilities (LTCFs) is high (25.9–68.8%) and is closely linked to malnutrition. However, few studies have examined this relationship specifically in LTCF residents. This study aimed to investigate the prevalence and co-existence of frailty and malnutrition and to identify factors related to frailty, including malnutrition, among older adults in Korean LTCFs.

**Methods:** This cross-sectional analysis used data from an ongoing longitudinal study. Data were collected from July 11, 2021, to January 23, 2022, in 16 LTCFs across six provinces in Korea. A total of 558 participants aged ≥65 years who had resided in the LTCF for >2 months and could communicate were included. Frailty was measured using the FRAIL-NH scale (version 2), categorizing participants as robust (0–1), prefrail (2–5), or frail (6–14). Nutritional status was assessed using the Mini-Nutritional Assessment short form (MNA-SF), classifying participants as normal (12–14), at risk of malnutrition (8–11), or malnourished (0–7). For analysis, nutritional status was dichotomized into normal (12–14) and malnutrition (0–11). Covariates included age, sex, hypertension, heart disease, stroke, comorbidities, urinary incontinence (UI), depressive symptoms, dry mouth, and grip strength. Data were analyzed using chi-square tests, univariate logistic regression, and multivariate logistic regression with backward selection.

**Key Results:** The mean age was 83.68 ± 7.39 years; 78.0% were female. Among participants, 37 (6.6%) were robust, 274 (49.1%) prefrail, and 247 (44.3%) frail. Malnutrition (including risk) was present in 75.8% (18.1% malnourished, 57.7% at risk). Co-existing frailty and malnutrition occurred in 228 participants (40.9%). In multivariate analysis, malnutrition was the strongest frailty-related factor: compared with normal nutrition, malnutrition increased the odds of frailty versus robustness by 10.35 times (95% CI: 3.78–28.36) and versus prefrailty by 4.80 times (95% CI: 2.69–8.59). UI was significantly associated with all frailty levels: prefrail vs. robust (OR 3.08, 95% CI: 1.44–6.62), frail vs. robust (OR 8.25, 95% CI: 3.19–21.34), and frail vs. prefrail (OR 2.05, 95% CI: 1.31–3.22). Comorbidities were associated with frail vs. robust (OR 1.67, 95% CI: 1.22–2.30) and frail vs. prefrail (OR 1.31, 95% CI: 1.15–1.51). Dry mouth (OR 2.96, 95% CI: 1.73–5.08) and lower grip strength (OR 0.95, 95% CI: 0.92–0.98) were significant only for frail vs. prefrail.

**Clinical Implications:** The high prevalence of frailty and malnutrition and their co-existence (40.9%) in LTCF residents underscores the urgent need for systematic screening and intervention. Malnutrition is a modifiable risk factor that strongly predicts frailty progression. Nursing staff should conduct regular nutritional assessments using tools like the MNA-SF and implement individualized nutritional support. UI, comorbidities, dry mouth, and low grip strength are additional targets for intervention. Given that factors differ by frailty level, tailored approaches are essential: for prefrail individuals, UI management may be key; for frail individuals, comprehensive strategies addressing nutrition, UI, comorbidities, oral health, and muscle strength are needed. Periodic screening and multidisciplinary interventions could prevent frailty worsening, reduce hospitalization and mortality, and improve quality of life in this vulnerable population.