Measurement of Skinfold Thickness in Subscapular Area to Monitor Hydration Status in Chronic Hemodialysis Patients.

Subscapular skinfold thickness decreased significantly during hemodialysis sessions.

• The mean change of skinfold thickness in subscapular area before and after hemodialysis session was -2.2 ± 1.6 mm.
• Measurements were taken directly before and at the end of three consecutive hemodialysis sessions.
• 50 participants were enrolled (21 female, 29 male; age 60 ± 15 years).
• Skinfold thickness was measured using a standardized caliper.

Change in extracellular water volume correlated significantly with change in subscapular skinfold thickness during hemodialysis.

• Correlation coefficient r = 0.33; p = 0.02 between change of extracellular water volume and skinfold thickness before and after hemodialysis.
• Extracellular water volume was measured by bioimpedance spectroscopy (BIA).
• A separate significant correlation was found between the change of total water volume and body mass before and after hemodialysis (r = 0.49; p < 0.01).

Change in subscapular skinfold thickness positively correlated with change in systolic blood pressure during hemodialysis.

• Correlation coefficient R = 0.36; p = 0.01 between change of skinfold thickness and systolic blood pressure before and after a hemodialysis session.
• This finding suggested a potential utility of skinfold measurement in monitoring blood pressure control in dialysis patients.

Dialysis vintage significantly correlated with changes of plasma nt-proBNP level during hemodialysis.

• Correlation coefficient r = 0.40; p = 0.02 between dialysis vintage and changes of plasma nt-proBNP level during hemodialysis.
• nt-proBNP (n-terminal pro-B-type natriuretic peptide) was measured from blood tests taken before and after hemodialysis sessions.

Multivariate analysis identified baseline body mass, BMI, and changes in systolic blood pressure as determinants of skinfold thickness variability during hemodialysis.

• Baseline body mass, BMI, and changes of systolic blood pressure determined the variability of skinfold thickness during hemodialysis in multivariate analysis.
• These findings suggest that skinfold changes are influenced by both anthropometric and hemodynamic factors.

BIA spectroscopy was more sensitive and specific than skinfold thickness assessment for evaluating hydration status.

• Receiver operating curve (ROC) analysis was used to compare the two methods.
• BIA spectrometry demonstrated greater sensitivity and specificity than skinfold thickness assessment for the assessment of hydration condition.
• Body composition with bioimpedance spectroscopy was measured directly before each hemodialysis session alongside skinfold measurements.
• The authors concluded that skinfold measurement 'may approximate changes of hydration status but are inferior to BIA spectroscopy.'