Dysphagia is more strongly associated with increased intramuscular adipose tissue of the quadriceps than with loss of muscle mass in older inpatients.

The purpose of this study was to examine the relationship between intramuscular adipose tissue of the quadriceps and dysphagia in older inpatients. We hypothesized that increased intramuscular adipose tissue of the thigh may indirectly reflect severe dysphagia in older inpatients. This study was cross-sectional, and 103 older inpatients participated. Patients who had stroke that was the obvious cause of dysphagia were excluded. Primary outcomes were intramuscular adipose tissue of the quadriceps and severity of dysphagia. Transverse ultrasound images were acquired using B-mode ultrasound imaging. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed based on echo intensity and muscle thickness, respectively. Severity of dysphagia was assessed using the Food Intake Level Scale (FILS). We used multiple regression analysis to identify the factors that were independently associated with FILS scores. Echo intensity, age, sex, body mass index, number of medications, C-reactive protein, Geriatric Nutritional Risk Index (GNRI), updated Charlson Comorbidity Index, muscle thickness, subcutaneous fat thickness of the thigh, and length of hospital stay were the independent variables. Echo intensity (β = -0.28), number of medications (β = 0.22), GNRI (β = 0.27), and subcutaneous fat thickness of the thigh (β = -0.29) were significantly independently associated with FILS scores. Muscle thickness was not significantly independently related to FILS scores (β = 0.08). In conclusion, our results suggest that increased intramuscular adipose tissue of the quadriceps in older inpatients is associated with dysphagia. Furthermore, this relationship was stronger than that between loss of muscle mass and dysphagia.