Simplified muscle mass measurement method may stand in for PMI in GI patients

Simplified methods can be acceptable alternatives of measuring muscle mass in patients with gastrointestinal (GI) and chronic liver diseases in settings where the gold standards are unavailable, a recent study has found.

Researchers conducted a retrospective analysis of 331 patients (mean age, 74±13 years; 62 percent male) with GI diseases and 81 (mean age, 75±11 years; 67 percent male) who had chronic liver disease. The psoas muscle index (PMI) was used as the standard for muscle mass measurement, and its comparators were the simplified PMI and the arm muscle area (AMA) methods.

In the GI cohort, both simple PMI (coefficient, 0.76; p<0.001) and AMA (coefficient, 0.57; p<0.001) were significantly correlated with PMI. The two simplified methods also shared a significant association with each other (coefficient, 0.47; p<0.001). These were also true when disaggregating by sex.

The two simple measurement methods likewise shared a positive and significant correlation with PMI in the chronic liver disease patients (p<0.001), which persisted even when stratifying by sex.

In identifying myopenia, the simplified PMI method had a sensitivity of 62 percent and a specificity of 90 percent. Its positive and negative predictive values were 78 percent and 81 percent, respectively. The AMA method, on the other hand, showed corresponding values of 62 percent, 79 percent, 62 percent and 79 percent. All of these were in comparison to PMI, which was taken as the gold standard method.

“Muscle mass measured by the AMA method and [simplified] PMI method showed some correlation with muscle mass measured using the PMI method,” researchers said. “In particular, the AMA method is a noninvasive muscle mass measurement method that can be performed without radiation exposure and can be performed conveniently at any institution.”