Longitudinal association of malnutrition risk with intramuscular adipose tissue of the quadriceps in older inpatients

Background In older inpatients, a higher malnutrition risk (MR) at the time of post-acute hospital admission has been associated with increased intramuscular adipose tissue (IMAT) of the quadriceps. However, it remains unclear whether changes in MR during hospitalization are related to changes in IMAT in this population. Aim This study was to examine the longitudinal association of MR with IMAT of the quadriceps in older inpatients. Methods One hundred ninety-six older inpatients (aged ≥ 65 years) participated in this longitudinal study. The Geriatric Nutritional Risk Index (GNRI) score was used to evaluate MR. IMAT of the quadriceps was assessed based on echo intensity (EI). The changes in GNRI score and quadriceps EI were calculated by subtracting these baseline values from the values at discharge. Multiple linear regression analysis, adjusted for confounding factors, was used to determine whether the change in GNRI score was significantly related to the change in quadriceps EI. Results The means of the changes in quadriceps EI and GNRI score were −2.5 ± 15.4 (a.u.) and −0.4 ± 6.0, respectively. The change in GNRI score (β = −0.16, p = 0.015) was significantly and independently associated with the change in quadriceps EI. Conclusion The results of this study indicate that an increase in MR in older inpatients is related to an increase in IMAT of the quadriceps, and an improvement in MR is associated with a decrease in IMAT of the quadriceps.