Increase in muscle mass of the quadriceps is related to decrease in intramuscular adipose tissue in convalescent stroke patients: A longitudinal study.

Background & Aims: A previous study indicated that an increase in muscle mass is related to a decrease in intramuscular adipose tissue in older peoples. However, the longitudinal relationship between muscle mass and intramuscular adipose tissue of stroke patients remains unclear. This study aimed to examine the longitudinal relationships between muscle mass and intramuscular adipose tissue of the quadriceps on the paretic and non-paretic sides in convalescent stroke patients.

Methods: This longitudinal study included 24 convalescent stroke patients. Ultrasound images were acquired at hospital admission and discharge using B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were evaluated with muscle thickness and echo intensity, respectively. Multiple regression analysis was performed to confirm whether changes in echo intensity of the quadriceps on the paretic and non-paretic sides were related to changes in muscle thickness of those. The age, sex, days from onset stroke, change in the subcutaneous fat thickness, and paretic lower extremity function were set as an independent variable.

Results: Change in echo intensity of the quadriceps on the paretic side (β = - 0.55, p = 0.018) was independently and significantly associated with changes in muscle thickness of the quadriceps on the paretic side. Similarly, change in echo intensity of the quadriceps on the non-paretic side (β = -0.55, p = 0.013) was independently and significantly associated with change in muscle thickness of the quadriceps on the non-paretic side.

Conclusions: Our findings indicate that muscle mass and intramuscular adipose tissue of the quadriceps are strongly and negatively correlated and an increase in muscle mass of the quadriceps is related to a decrease in intramuscular adipose tissue on the paretic and non-paretic sides in convalescent stroke patients. Furthermore, we must recognize that convalescent stroke patients with a decrease in muscle mass have an increase in intramuscular adipose tissue.