Statistical analysis
Descriptive statistics of sociodemographic and clinical data and
quality-of-life questionnaires (EORTC and EuroQol-5d) and anxiety and
depression scales (the HAD questionnaire) were measured as means and
standard deviations and as frequencies and percentages for continuous
variables and categorical data, respectively. To evaluate the influence
of CT scanning, colonoscopy, chemotherapy and radiotherapy performed
throughout the follow-up on the different outcomes, univariable
generalized linear mixed models were used. Furthermore, multivariable
generalized linear mixed models were used to evaluate the effect of
those variables on mortality, complications, and recurrence at the next
follow-up visit.
In the same way, univariable and multivariable generalized linear mixed
models were used to evaluate the influence of the different quality
indices in the health-related quality of life and anxiety and depression
scales of the patients in the same follow-up period.
All the models were adjusted by sex, age, TNM stage, Charlson
comorbidity index, tumor location (colon or rectum) and hospital. The
variability explained by each model was determined by the coefficient of
determination (R2).
All effects were considered significant at p<0.05. All
statistical analyses were performed using SAS 9.4 (SAS Institute Inc.,
Cary, NC, USA).