Quadriceps Muscle Layer Thickness and its association with frailty in critically ill patients: A prospective observational study

Frailty is a well-recognized clinical entity known to influence the outcomes of critically ill patients. Muscle ultrasound, particularly Quadriceps Muscle Layer Thickness (QMLT), assesses muscle mass, which is a key component determining frailty. However, no studies have assessed the association between frailty and QMLT. This study aimed to determine the association between the QMLT and frailty in critically ill elderly patients. In this prospective, observational, single-center study conducted in an ICU in India, patients aged >65 years were enrolled. Baseline frailty was assessed using the Clinical Frailty Scale (CFS). Quadriceps muscle thickness was measured via axial cross-section ultrasound at admission. Patients were categorized as non-frail (CFS 1–4) and frail (CFS ≥5), and their characteristics were compared. Multivariate regression analysis was used to identify factors associated with frailty. 120 patients were included. The median APACHE II and SOFA scores were 19 [IQR 14.25–23] and 4.5 [IQR 3–6], respectively. The median age was 75 years [IQR 70–82]; 62.5 % were male. The most common comorbidities were diabetes mellitus (60 %) and hypertension (59 %). 65 % were mechanically ventilated. 65 % of patients were frail. Frail patients had higher mortality (37.17 % vs. 16.66 %, p = 0.022). QMLT was lesser in frail than non-frail (1.77 cm vs 2.21 cm, p