151751-Najiba-Chargi

59 Diagnostics: measuring skeletal muscle mass of the musculus masseter BODY COMPOSITION MEASUREMENTS Weight and height were recorded during patient’s first consultation at our out-patient clinic and used to calculate Body Mass Index (BMI) and Body Surface Area (BSA) using the Mosteller formula. 24 Lumbar skeletal muscle index (LSMI), cervical skeletal muscle index (CSMI) and masseter skeletal muscle mass index (MSMI) were calculated by dividing the corresponding patient’s CSA values by patient’s squared height. There is, to our knowledge, no scientific consensus on a cut-off value for MSMI. We therefore designated patients present in the lowest quartile of MSMI for their specific gender as “low MSMI”. OVERALL SURVIVAL The status of the patient (alive/deceased) was acquired from the UMCU electronic patient data system on date of last follow-up. Overall survival (OS) was defined as the time between the date of histologic diagnosis and death, or date of last follow-up. UMCU patient system is linked to the provincial government register and is updated continuously for patients living in the Utrecht province. Patients were considered alive if no date of death was available on date of last follow-up or if there was no physician note reporting on their death. Cause of date was determined by physician’s notes. STATISTICAL ANALYSIS SPSS 26 for Windows (IBM, Armonk, NY, U.S.A.) was used for analysis. Descriptive statistics were calculated with the continuous variables presented as mean (standard deviation) or median (interquartile range). Discrete variables were displayed as counts (percentages). Nor - mality was investigated by using the Kolmogorov-Smirnov test. Characteristics and muscle measurements were analyzed using independent-samples t-test for normally distributed vari- ables, independent-samples test for skewed variables and Fisher’s exact test or Pearson’s chi-squared test for categorical variables. Spearman correlation coefficients were calculated to establish the relationship between L3measurements, C3measurements andmasseter mea- surements. A correlation coefficient of (-)0.8 to (-)1 was interpreted as a very strong correlation, (-)0.6 – 0.8 as strong, (-)0.4 to (-)0.6 as moderate, and (-)0.2 to (-)0.4 as a low correlation. 25 Radiological measurements and patient characteristics were analyzed using Cox regression proportional hazards first as univariate analysis. Variables with a p-value lower than 0.05 and dental status were included for multivariate analysis. The backward step-method was chosen for multivariate analysis. The influence of MSMI and low lumbar SMI using the cut-off established by Wendrich et al. 11 on overall survival was evaluated using Kaplan-Meier curves and associated Log-Rank tests. 4