Measuring quadriceps femoris muscle (QFM) thickness via 2D ultrasound at the two-thirds femur point without probe pressure achieved 100% sensitivity and 43% specificity for ruling out malnutrition in 30 heart failure outpatients, validated against the GLIM criteria as the reference standard. Intraclass correlation coefficients ranged from 0.943 to 0.996, confirming excellent intra- and inter-operator reproducibility, and ROC analysis yielded an AUC of 0.74 at the optimal measurement site.
Malnutrition affects an estimated 16–50% of heart failure patients and independently predicts worse outcomes, yet routine nutritional screening remains inconsistently implemented in cardiology clinics. Muscle wasting — sarcopenia — is a well-established surrogate of systemic nutritional decline, and ultrasound offers a radiation-free, bedside-accessible means to quantify it. The 100% sensitivity at the two-thirds QFM point is clinically meaningful: a negative result could confidently discharge patients from further nutritional workup, streamlining clinic resources. However, the 43% specificity is low, meaning the tool generates many false positives requiring follow-up assessment.
Critical limitations temper enthusiasm: the sample of just 30 participants is far too small to establish reliable cutoff thresholds, and the cross-sectional design cannot address whether muscle thickness predicts clinical trajectory. As a preprint posted on medRxiv and not yet peer-reviewed, these findings should be treated as hypothesis-generating only — the authors themselves flag the need for larger validation cohorts. Overall, this is an incremental but practically oriented pilot contribution to bedside nutritional screening in cardiology.