Association between muscle strength and echogenicity using greyscale ultrasound software: a diagnostic accuracy study in kidney transplant candidates.
Carolina Acu��a-Pardo, Elena Mu��oz-Redondo, Lou Delcros-Forestier, Yulibeth G Curbelo, Carlos Rodr��guez-Hern��ndez, Delky Meza-Valderrama, Dolores S��nchez-Rodr��guez, Julio Pascual, Maria J P��rez-S��ez, Ester Marco
Author Information
Carolina Acu��a-Pardo: Department of Physical Medicine and Rehabilitation, Hospital del Mar, Barcelona, Spain.
Elena Mu��oz-Redondo: Department of Physical Medicine and Rehabilitation, Hospital del Mar, Barcelona, Spain.
Lou Delcros-Forestier: Department of Physical Medicine and Rehabilitation, Hospital del Mar, Barcelona, Spain.
Yulibeth G Curbelo: Department of Physical Medicine and Rehabilitation, Hospital del Mar, Barcelona, Spain.
Carlos Rodr��guez-Hern��ndez: Department of Physical Medicine and Rehabilitation, Hospital del Mar, Barcelona, Spain.
Delky Meza-Valderrama: Rehabilitation Research Group, Hospital del Mar Research Institute, Barcelona, Spain.
Dolores S��nchez-Rodr��guez: Rehabilitation Research Group, Hospital del Mar Research Institute, Barcelona, Spain.
Julio Pascual: Nephropathies Research Group, Hospital del Mar Research Institute, Barcelona, Spain.
Maria J P��rez-S��ez: Nephropathies Research Group, Hospital del Mar Research Institute, Barcelona, Spain.
Ester Marco: Department of Physical Medicine and Rehabilitation, Hospital del Mar, Barcelona, Spain - emarco@psmar.cat.
BACKGROUND: Advanced chronic kidney disease disrupts the delicate equilibrium between protein anabolism and catabolism, leading to alterations in muscle quantity, quality, and function. Musculoskeletal ultrasound emerges as a promising assessment tool due to its widespread availability and high reliability. AIM: To evaluate the efficacy of rectus femoris (RF) echogenicity, measured using greyscale software, in identifying diminished muscle quality and strength in candidates for kidney transplant. DESIGN: Post-hoc diagnostic accuracy study. SETTING: Outpatients in a multimodal prehabilitation program pre kidney transplantation (KT). POPULATION: patients on the waiting list for KT. METHODS: Sensitivity, specificity, likelihood ratios and area under the curve (AUC) for diagnostic efficacy of echogenicity (index test) assessed with the ImageJ software greyscale as a potential marker of quadriceps Muscle weakness (reference test) were calculated. Muscle weakness was considered as maximal voluntary isometric contraction of the quadriceps (Q-MVIC) <40% of body weight. Other variables included body composition parameters derived from multifrequency electrical bioimpedance, upper limb muscle strength (handgrip), and RF thickness assessed by ultrasound. Statistical tests: Chi-square, t-Student, Pearson correlation coefficients (r), bivariate and multivariate logistic regression models. Statistical significance level ���0.05. RESULTS: Of 112 patients (mean age: 63.6, 76% male), 72 (63.7%) exhibited quadriceps weakness, while 80 (70.8%) had some degree of overhydration (extracellular water/total body water ratio >0.390). The echogenicity cut-off point of highest concordance with Muscle weakness was 70, boasting a sensitivity of 83%, specificity of 57%, and AUC of 0.671 (CI 95% 0.570-0.772 [P=0.003]). Echogenicity >70 was associated with a 3.4-fold higher risk of Muscle weakness (crude OR = 3.4 [CI95% 1.4 to 8.0]), which persisted after adjusting for age, height, weight and RF thickness. CONCLUSIONS: The RF echogenicity exhibits fair validity in identifying Muscle weakness among candidates for KT. However, it cannot be endorsed as a standalone diagnostic tool in this population. CLINICAL REHABILITATION IMPACT: Early identification of Muscle weakness would advance efforts to mitigate morbidity and mortality through targeted measures.
