A new anthropometry-based muscle quality index predicts adverse outcomes in hospitalized patients

Muscle quality index (MQI) is computed as the ratio of strength to muscle mass (MM), estimating functional muscle quality. Imaging methods are used to assess MM and compute the MQI, being challenging for use in clinical practice. Anthropometry has become an alternative marker of MM that can be used within MQI, although few studies have explored this approach.

To evaluate the prognostic value of mid-arm muscle circumference (MAMC cm), corrected arm muscle area (AMA cm²), and calf circumference adjusted for body mass index (CC-BMI adjusted cm) as markers of MM within MQI in predicting adverse outcomes in hospitalized patients.

A secondary analysis was conducted on a cohort with prospective data collection. Adult and older hospitalized patients were evaluated up to 48 h after hospitalization. MQI was calculated as the ratio of handgrip strength (HGS) to MM evaluated by MAMC (MQI_MAMC), MAM (MQI_MAM), and CC-BMI adjusted (MQI_CC-BMI). The outcomes of interest were prolonged hospital stay, in-hospital and 6-month mortality. Logistic and Cox regression analyses adjusted for Charlson comorbidity index, ethnicity, surgery, and sex were performed.

554 patients were included (55.2 ± 14.9 years, 52.9 % of males, 518 had MACM and MAM available). Each one-unit MQI increase reduced the risk by 32 %, 44 %, and 33 % in prolonged hospitalization for MQI_MAMC (RR = 0.68, 95 % CI 0.52-0.90), MQI_AMA (RR = 0.56, 95 % CI 0.35-0.89), and MQI_CC-BMI (RR = 0.67, 95 % CI 0.46-0.96). A higher MQI_CC-BMI was an independent predictor of a lower risk of 6-month mortality after discharge (RR = 0.26, 95 % CI 0.08-0.84).

Higher MQI values using anthropometric markers (MAMC, AMA, and CC-BMI) were inversely associated with adverse in-hospital and 6-month after-discharge outcomes, reinforcing its use as a muscle-related prognostic index.