For windows version 12

This was a cross-sectional study in which consecutive patients who underwent EPLBD during the defined period were evaluated based on study endpoints. Statistical analyses were performed using MedCalc for Windows, version 12.5 (MedCalc Software, Ostend, Belgium). Simple statistical applications were applied in order to determine whether significant differences exist in comparison groups. We initially used simple proportions to describe the study populations. Furthermore, we used chi-square test to compare proportions and categorical variables. Non-parametric Mann-Whitney U-test was applied in order to compare continuous variables. All comparisons were deemed to be statistically significant if P values were less than 0.05.

First, survival and death groups were compared using the chi-squared test. TRISS and GTOS equations were used for all included patients. The TRISS method equation is presented as follows:


TRISS took into account the patient’s age in an AgeIndex: “0” for patients aged under 55 years and “1” for patients aged 55 years and above. The GTOS equation was applied to patients as follows:

We plotted the receiver operating characteristic (ROC) curves of the results and deduced the areas under the curve (AUCs), 95% confidence interval (CI), and difference between the areas. We also compared two ROC curves with the null hypothesis that GTOS is not inferior to the TRISS. Comparison of the AUCs followed the method introduced by DeLong, et al.13 (link) Similar processes were performed for various subgroups, which were 1) patients aged ≥70 years, 2) patients aged ≥75 years, 3) patients with ISS ≥9, 4) patients with ISS ≥15, 5) patients transferred from another hospital, and 6) patients who arrived directly from the scene. The respective ISS cutoff values for major and severe trauma were 9, which was introduced by Hannan, et al.,14 (link) and 15, as suggested by Copes, et al.,15 (link) All statistical analyses were performed using MedCalc for Windows version 12.5 (MedCalc Software, Ostend, Belgium).

Descriptive statistics included mean and standard deviation for continuous variables. As both eyes of most subjects were included for analysis, the correlation between the two eyes of the same subject was adjusted using generalized estimating equations (GEEs) during the calculation of the summary of the descriptive parameters. Univariate regression models (based on past studies) were adjusted using GEE and were used to assess significant associations between CT and independent parameters such as age, gender, and duration of diabetes. One-way analysis of variance (ANOVA) and the unpaired t-test were used wherever appropriate. The multivariate models that were adjusted using GEE methods were used to assess the effects of age, gender, SE, and macular thickness on the CT measurements. Statistical analyses were performed using MedCalc for Windows, version 12.5 (MedCalc Software, Ostend, Belgium). The alpha level (Type I error) was set at 0.01. All the graphs were performed using GraphPad Prism version 6.00 for Windows (GraphPad Software, La Jolla California, USA, www.graphpad.com). Statistical significance was set at P < 0.05.