INSTRUMENTS

This form was developed specifically for this study to obtain data that would allow the participant to be characterized with respect to sociodemographic aspects (gender, age, education, occupation, civil status, children, race, and religion) and clinical medical record data (underlying disease, time on treatment, comorbidities, vascular access, and laboratory exams).

The Beck Depression Inventory - Second Edition (BDI-II) was chosen to evaluate depression symptoms. This instrument was originally created by Beck, Ward, Mendelson, Mock, and Erbaugh in 1961 and reviewed by Beck, Rush, Shaw, and Emery in 1979/1982.26 The BDI-II is a self-administered instrument comprising 21 items, each of which has four statements relating to content with increasing degrees of depression severity, with scores ranging from zero to three. The Brazilian version of the second edition was developed by Gorenstein et al.27 The depression intensity classification, according to the BDI-II score, is as follows: minimum - 0-13; mild - 14 to 19; moderate - 20-28; and severe - 29-63. In this study, scores ≥ 14 points were considered to indicate the presence of depressive symptoms.

The instrument chosen to evaluate HRQOL was the Kidney Disease and Quality of Life Short Form (KDQOL-SF) in its translated version, adapted and validated for Brazilian culture.28 The dimensions of the KDQOL-SF(tm) are measured on a standardized scale ranging from zero (worst score - unfavorable HRQOL) to 100 (best score - favorable HRQOL), with higher scores indicating better health. This scale is considered easy to understand and administer. The instrument includes the Short-Form Health Survey (SF-36) as a generic measure that evaluates eight domains of the patient's physical and mental health. In addition, to address the CKD patient, 12 specific dimensions are included with respect to the disease.

Initially, a descriptive analysis with data consistency check was performed. The prevalence of depressive symptoms and the mean score obtained on the BDI-II, in addition to the means obtained in the different QOL domains according to the KDQOL-SF, were calculated with the respective standard deviations. Data are presented as the mean±standard deviation or median (first and third quartile), where appropriate.

The t-test for paired samples (for data with a normal distribution) and the Wilcoxon test (for data with a non-normal distribution) were used to compare the data collected at stages 1 and 2, and the chi-squared test was used for categorical variables. In addition to these comparisons, correlations were examined between the KDQOL-SF dimensions, the score obtained on the BDI-II, and the demographic variables, using Pearson's correlation coefficient. P values < 0.05 were considered significant in all analyses. SPSS 12.0 was the statistical program used for data storage and analysis.