Sonoelastographic evaluation of diaphragmatic thickness and stiffness in dialysis patients

OBJECTIVES: This study aimed to quantitatively and noninvasively assess diaphragmatic alterations in patients with end-stage renal disease undergoing hemodialysis (HD) or peritoneal dialysis (PD) using ultrasonography (US) and shear wave elastography (SWE). METHODS: This prospective cross-sectional study included 69 dialysis patients (HD, n = 37; PD, n = 32) and 60 demographically matched healthy controls. Right hemidiaphragm was evaluated using greyscale US and SWE through the 8th–10th intercostal spaces in the mid-axillary line. Thickness and stiffness were measured at end-expiration and peak inspiration phases. Clinical data, laboratory parameters, and dialysis-related metrics were recorded. Comparative and correlational analyses were performed using appropriate statistical methods. RESULTS: At peak inspiration, the measurements were 2.24 ± 0.25 mm and 25.61 ± 6.15 kPa for the HD group, 2.53 ± 0.23 mm and 32.79 ± 5.31 kPa for the PD group, and 2.86 ± 0.29 mm and 47.68 ± 6.67 kPa for the control group. Significant differences were observed between the groups for both parameters (p < 0.001). At end expiration, diaphragm thickness and stiffness were 1.69 ± 0.20 mm/19.46 ± 4.37 kPa, 1.75 ± 0.19 mm/22.62 ± 4.84 kPa, and 2.00 ± 0.19 mm/33.26 ± 4.62 kPa in the HD, PD, and control groups, respectively. There were significant differences between the groups (p < 0.05). ROC analysis indicated excellent diagnostic performance of these parameters for distinguishing dialysis patients from controls (AUC 0.806–0.987). Furthermore, diaphragm parameters correlated significantly with dialysis duration, adequacy, comorbidity, and serum albumin levels. CONCLUSION: Diaphragm thickness and stiffness are reduced in dialysis patients, especially those on hemodialysis. US and SWE may serve as early imaging biomarkers for respiratory sarcopenia.