Spss statistics for window version 22

Descriptive data were calculated for the number of registrations, country of registration, and type of study. The number of patients was calculated by addition of the number of patients reported in the study registration for all 500 registrations. Inter-rater reliability was calculated for the quality criteria, and quality of registrations are presented on a month-by-month basis. An independent samples Kruskal–Wallis test was performed to ascertain if there was a significant difference between median month-by-month quality scores. All data were managed using Microsoft Excel 2013 (Microsoft, Redmond, VA, USA), statistical analysis was performed using IBM SPSS Statistics for Window, Version 22.0 (IBM Corp., Armond, NY, USA).

To asses differences among carbon sources or between mono- and co-cultures, one-way ANOVAs followed by SNK (Student-Newman-Keuls, p < 0.05) mean comparison test were performed. The statistical package IBM SPSS Statistics for Window Version 22.0 (IBM Corp., Armonk NY) was used to carry out these analyses.

A descriptive analysis was performed. Categorical variables were summarized by proportions and quantitative continuous variables by median and interquartile range (IQR) for non-normally distributed variables, and mean and standard deviation (SD) for normally distributed variables. When information was missing, the denominator accounted for patients with available data. Comparisons between categorical data were performed using Fisher’s exact test. For numerical data, comparisons were performed with the Student’s t-test for parametric and the Mann–Whitney U test for nonparametric data. Overall survival curves were calculated using the Kaplan–Meier method and compared with log-rank test. All calculations were performed with the 22.0 SPSS software package (IBM SPSS Statistics for Window, Version 22.0. Armonk, NY, USA). All tests were two-sided and a p-value of less than 0.05 was considered statistically significant.