Published online Aug 8, 2020. doi: 10.4292/wjgpt.v11.i3.59
Peer-review started: December 29, 2019
First decision: March 27, 2020
Revised: May 17, 2020
Accepted: May 21, 2020
Article in press: May 21, 2020
Published online: August 8, 2020
Processing time: 219 Days and 20.8 Hours
Malnutrition affects 40%-90% of patients with cirrhosis of the liver. L3 skeletal muscle index (L3SMI) is presently accepted as the most objective and quantitative measure available for sarcopenia, a surrogate marker of malnutrition. L3SMI application is, however, limited by non-availability of computed tomography scanning in remote areas, cost, need for extensive training, and the risk of exposure to radiation. Therefore, an alternative dependable measure with wider availability is needed. Malnutrition causes sarcopenia not only in skeletal muscles but also in other muscular structures such as the psoas muscle, diaphragm and tongue. We therefore hypothesised that the tongue, being easily accessible for inspection and for measurement of thickness using ultrasonography, may be used to document sarcopenia.
To measure and compare tongue thickness in healthy individuals and in patients with cirrhosis of the liver and to study its correlation with conventional prognostic scores for patients with cirrhosis of the liver.
Tongue thickness was measured using ultrasonography. One hundred twenty subjects of either gender aged 18 to 65 years were studied, with 30 subjects in each group. The tongue thickness was compared between groups based on “Child Turcotte Pugh” (CTP) scores. The correlations between measured tongue thickness and “Model for end stage liver disease” (MELD) score and between age and measured tongue thickness were also assessed.
Mean tongue thickness (mean ± SD) in patients with CTP class A, B and C was 4.39 ± 0.39 cm, 4.19 ± 0.53 cm, and 3.87 ± 0.42, respectively, and was 4.33 ± 0.49 cm in normal healthy individuals. Significant differences were seen in tongue thickness between patients with CTP class C and those with CTP class A and B (P < 0.05). Patients with CTP class C also had a significantly reduced tongue thickness than normal individuals (P < 0.05). However, no significant difference was seen in tongue thickness between patients with CTP class A and B and normal individuals. A statistically significant, negative correlation was found between MELD score and tongue thickness (r = -0.331) (P < 0.001). No correlation was observed between L3SMI and MELD score (r = 0.074, P = 0.424). L3SMI (mean ± SD) in healthy subjects was 39.66 ± 6.8 and was 38.26 ± 8.88 in patients with CTP class C, and the difference was not significant. No significant correlation was found between age of the patients and tongue thickness. Intra-class correlation coefficient was used to determine the reliability of the tongue thickness measurements. The intra-class correlation coefficient was 0.984 (95%CI: 0.979-0.989) and was indicative of good reliability.
Tongue thickness measured by ultrasonography, correlates significantly with the severity of liver disease, as assessed by CTP and MELD scores. The patients with a CTP score ≥ 10 have significantly reduced tongue thickness as compared to normal individuals and those with less severe liver disease and CTP scores of 5-9. No significant difference in tongue thickness was found between healthy individuals and CTP class A and B patients.
Core tip: Sarcopenia has implications for the management and outcome of patients with cirrhosis of the liver and is therefore included in prognostication. However, the only objective and reproducible measure for sarcopenia using computed tomography (CT) scanning which measures skeletal muscle thickness, is the L3 skeletal muscle index (L3SMI). However, the application of L3SMI is restricted by the need for CT scanning. Compared with CT scan measured L3SMI, tongue thickness can easily be measured in a reproducible manner and accurately with minimal training using ultrasonography and as suggested by this study, is a more sensitive indicator of sarcopenia. Further studies are required to validate these findings and propose tongue thickness as a tool to diagnose sarcopenia.