Longitudinal relationship between intramuscular adipose tissue of the quadriceps and activities of daily living in older inpatients

Abstract

Background The longitudinal relationship between intramuscular adipose tissue of the quadriceps and activities of daily living (ADL) in older inpatients remains unclear. This study aimed to examine whether decrease of intramuscular adipose tissue of the quadriceps in older inpatients is related to the recovery of ADL than increase of muscle mass. Methods This longitudinal study included 202 inpatients aged ≥65 years [median age: 83.0 (77.0–88.0), 56.4% female]. Recovery of ADL during hospital stay was assessed using the change in Barthel index (BI) score (i.e. BI score at discharge minus BI score at admission) and BI score at discharge. Intramuscular adipose tissue and muscle mass of the quadriceps were assessed using echo intensity and muscle thickness on ultrasound images, respectively. Higher echo intensity indicates greater intramuscular adipose tissue. Multiple regression analysis was performed to identify the factors independently associated with the change in BI score and BI score at discharge. Changes in quadriceps echo intensity and thickness and subcutaneous fat thickness of the thigh, quadriceps echo intensity and thickness, and subcutaneous fat thickness of the thigh at admission, age, sex, days from onset disease, BI score at admission, and disease were set as independent variables. Results The means of the change in quadriceps echo intensity and thickness were −2.3 ± 15.7 and 0.1 ± 0.4 cm, respectively. The median of the change in BI score was 15.0 (0.0–30.0). The quadriceps echo intensity at discharge was significantly lower than at admission (P = 0.043). The quadriceps thickness (P = 0.004) and BI score at discharge (P < 0.001) were significantly higher than those at admission. Change in quadriceps echo intensity was independently and significantly associated with the change in BI score (β = −0.25, P = 0.006) and BI score at discharge (β = −0.18, P = 0.006). In contrast, change in quadriceps thickness was not independently and significantly associated with the change in BI score (β = 0.09, P = 0.244) and BI score at discharge (β = 0.06, P = 0.244). Conclusions Our study indicates that a decrease of intramuscular adipose tissue of the quadriceps is related to the recovery of ADL than an increase of muscle mass in older inpatients. Intramuscular adipose tissue of the quadriceps in older inpatients is considered to be a predictor for the recovery of ADL, and intervening for intramuscular adipose tissue may be important for improving ADL in older inpatients.

Reliability and Validity of Quadriceps Muscle Thickness Measurements in Ultrasonography: A Comparison with Muscle Mass and Strength

“…In future studies, US should be used to assess muscle quality, as recently reported Akazawa et al, who used US to measure muscle echo intensity to assess muscle quality. 26) Muscle quality should be evaluated together with muscle thickness and their impact on physical function and functional prognosis should be investigated in the future. Third, this study was conducted using a portable US device and cannot be generalized to all US devices.…”

The degree of recovery in swallowing ability in older inpatients with aspiration pneumonia is related to intramuscular adipose tissue of the quadriceps than to muscle mass

“…Additionally, appendicular skeletal muscle mass is related to knee extension strength [ 44 , 45 ], gait ability [ 46 ], and ADL [ 47 , 48 ]. However, intramuscular adipose tissue in the quadriceps shows increased association with knee extension strength [ 25 – 27 ], gait ability [ 28 – 30 ], and ADL [ 31 , 32 ] as compared to muscle mass. These findings indicate that in contrast to muscle mass, intramuscular adipose tissue of the quadriceps is indirectly related to swallowing ability.…”

“…In addition, the effects of aging and disuse are remarkably observed in the quadriceps of the upper and lower extremity muscles [ 63 , 64 ]. Furthermore, intramuscular adipose tissue in the quadriceps of older inpatients has been reported to be related to gait ability [ 28 – 30 ], ADL [ 31 , 32 ], and the onset of hospital-associated complications [ 65 ]. Based on these findings, targeting the quadriceps was considered valid in this study.…”

Increased intramuscular adipose tissue of the quadriceps at admission is more strongly related to activities of daily living recovery at discharge compared to muscle mass loss in older patients with aspiration pneumonia

“…An increase in the intramuscular adipose tissue is more strongly associated with decreased muscle strength [ 7 , 8 ] and gait ability [ 9 ] and increased mortality [ 10 , 11 ] than the loss of muscle mass. Additionally, an increase in the intramuscular adipose tissue of the quadriceps of older patients decreases ADL [ 12 – 14 ] and the swallowing ability [ 15 ] and is related to hospital-associated complications [ 16 ] more so than the loss of muscle mass. Therefore, an increase in the intramuscular adipose tissue of the quadriceps is considered a severe problem for older individuals.…”

“…A previous study [ 18 ] reported that the decrease in ADL among patients with aspiration pneumonia is remarkable and that improving ADL among these patients is difficult. Because increased intramuscular adipose tissue of the quadriceps of older patients negatively affects ADL recovery more so than the loss of muscle mass [ 12 – 14 ], it is considered strongly related to ADL recovery among such patients. However, whether intramuscular adipose tissue of the quadriceps of older patients with aspiration pneumonia is related to ADL recovery after hospitalization remains unclear.…”