2.1. Study Design
This work is a cross-sectional study conducted in the cadre ward of the First Hospital of Jilin University from December 2020 to June 2021. Inpatients aged 65 years or above were recruited. Patients who were unable to walk for neuromusculoskeletal diseases such as Parkinson's disease, severe knee or hip osteoarthritis, lumbar spinal stenosis, and Participants with malignant tumors, severe cognitive impairment, autoimmune diseases, severe liver and kidney dysfunction were excluded from the study. The study was in line with the declaration of Helsinki Declaration and approved by the ethics committee of the First Hospital of Jilin University.
2.2. Measurements
2.2.1. General information
Age, gender and exercise were evaluated by self-made face-to-face interview questionnaire.
Clinical information comes from electronic medical records, including smoking history, drinking history, types and diseases of chronic diseases, hemoglobin, albumin, prealbumin, cholesterol, triglyceride and low density lipoprotein Cholesterol.
2.2.2. Anthropometric measurements
(1) Height and weight were measured according to clinical standards.
(2) Body mass index (BMI) was calculated as weight (kg) divided by height (m) squared.
(3) Walking speed was calculated as 4.57 m walk time divided by 4.57 m. Participants walked at daily speed. Time was recorded with a stopwatch (accurate to 0.01 second). The average value was calculated after the second measurement.
(4) Handgrip strength of the dominant hand was measured by handgrip dynamometer(JAMAR@Plus)for 3 times, and the maximum handgrip strength was taken for analysis.
(5) Participants stood with their feet shoulder width apart and the calf circumference around the most prominent part of the gastrocnemius muscle was measured (accurate to 0.1 cm).
(6) Arm circumferenceat the level of the thickest part of biceps brachii muscle was measured with the upper limb sags naturally (accurate to 0.1 cm).
2.2.3. Frailty Assessment
Frailty was defined as a major biological phenotype by Fried Frailty Phenotype [10]. Satisfying three or more of the five followings were diagnosed as frailty syndrome, including weight loss of more than 4.5 kg or > 5%, fatigue, less physical activity, slow pace and weak handgrip in the past year. Fatigue refers to feeling that everything needs effort or can't move forward for three or more days. The decrease of handgrip strength was estimated by lower limit of handgrip strength which was determined according to the subjects' gender and body mass index. Male < 383 kcal / week or female < 270 kcal / week was judged as physical activity decrease. Walking speed was calculated by the time required to walk 4.57 meters, male with height ≤ 173 cm, walking speed ≥ 7 s or height > 173 cm, walking speed ≥ 6 s was identified as walking speed descent; while the standard of walking speed descent among female is height ≤ 159 cm, walking speed ≥ 7 s or height > 159 cm, walking speed ≥ 6 s.
2.2.4 Malnutrition
Mini Nutritional Assessment (MNA) is a nutritional assessment tool with 18 questions specially developed for the elderly. It consists of four parts: anthropometry (body mass index, calf circumference and arm circumference measurement), self reported health status, dietary problems (including weight loss) and clinical health status. MNA was used to comprehensively evaluate the nutritional status of elderly patients [11, 12]. The total score of MNA is 30 points, if the score was < 17 points, patients were classified as malnutrition; if the score was between 17 to 23.5 points, subjects were at the risk of malnutrition; good nutrition, if the score was > 23.5 points.
2.3. Data Analysis
SPSS/WIN 23.0 software was used for statistical analysis (IBM Corp., Armonk, NY, USA). Continuous variables were analyzed using mean and standard deviation, and classified variables were analyzed using percentage. In order to determine the impact of malnutrition on senile frailty patients, after adjusting for confounding factors, multivariate Logistic regression analysis was used to observe the OR value and 95% confidence interval. The AUC value was calculated by drawing ROC curve to identify the predictive value of different nutritional indexes for senile frailty patients. Values of p ≤ 0.05 were considered statistically significant.