The study involved 200 participants who met the inclusion criteria for the research (84 F, 116 M; age 61 ±12 years): 160 patients with CKD stage G4-G5 from a nephrology clinic and hemodialysis unit and 40 healthy people constituting a control group. Depending on the stage of the disease and length of dialysis treatment the patients were divided into five groups of 40 people each: Group 1 – a control group, healthy people; Group 2 – patients in the pre-dialysis care (BD) with CKD stage G4-G5; Group 3 – hemodialysed patients (HD) treated less than 1 year; Group 4 - HD 1-5 years and Group 5 - HD > 5 years. The inclusion criteria enclosed: age ≥ 18 years, voluntary consent to participate in the study, diagnosed chronic kidney disease, stage G4-G5 (Groups 2-5). The exclusion criteria were: decompensated heart failure, acute medical conditions (e.g. fever, pain), lack of consent to participate in the research.
The Local Bioethical Committee approved our study. All the investigated persons were informed about the principles and purpose of the research. They gave their consent to their participation. The diagnostic poll method was used in the work which employed the following questionnaires:
Health Behaviour Inventory (IZZ) [7]. The questionnaire consists of 24 statements describing health-related behaviours. It helps to measure the general intensity of health behaviours and intensity of 4 categories of health behaviours: appropriate eating habits - PN1, prophylactic behaviours - ZP, positive mental attitude - PN2 and health practices - PZ. The person surveyed rates the frequency of a particular behaviour on a 5-point frequency scale (1 – almost never, 2 – rarely, 3 – from time to time, 4 – often, 5 – almost always). The value of the indicator ranges from 24-120 points. The higher the result is, the higher the intensity of declared health behaviours is. After converting into standardised units, the general index is interpreted as a sten score. The questionnaire is sufficiently reliable for the IZZ general result (α = 0.85) and for individual scales (Cronbach’s alpha fluctuated between 0.60 and 0.65). ). The IZZ has good psychometric properties in patients with CKD [8].
PersonalityInventory (NEO-FFI) [9]. The sheet contains 60 items – 12 for each of 5 scales: Neuroticism (NEU), Openness to experience (OTW), Agreeableness (UGD), Conscientiousness (SUM), Extraversion (EKS). The person surveyed marks a response on a 5-point scale (1 – strongly disagree, 2 – disagree, 3 – have no opinion, 4 – agree, 5 – strongly agree). The raw result on each scale ranges from 0 to 48; the result is interpreted in sten scores. The standards are made separately for men and women with a subdivision into five age groups. A higher result on a given scale means the higher intensity of a particular personality trait. Cronbach’s alpha for scales is between 0.68 and 0.82). The NEO-FFI has good psychometric properties in patients with CKD [10].
Researcher’s questionnaire test was developed for this work. It was to collect socio-demographic (age, gender, marital status, number of people in the household, presence of the household assistant, professional activity, nature of work, domicile, financial status, having children, the recent loss of a close person, stimulants) and clinical (time from starting dialysis, number of medications taken, comorbidities, disorders between dialyses, qualifying for a transplant, transplantation in the disease history, type of vascular access, dialysis frequency and duration time, distance and transportation to the dialysis unit) data.
Beck Depression Inventory is a tool to assess depression symptoms in adults and youth before 13 years of age [11]. The test consists of 21 multiple-choice questions which the person surveyed answers by choosing 1 of 4 possible options. Each response is assigned a value from 0 to 3, which corresponds to the depression severity in a given area (among others, mood, interests, appetite, sleep quality). The BDI has good psychometric properties in patients with CKD.
The datasets used and analysed during the current study are available from the corresponding author on reasonable request.
Statistics
The PQ Stat 1.6.8 statistical package was used for carrying out statistical analysis. In the study, descriptive statistics were applied for quantitative and qualitative variables (the mean with standard deviation, the median with minimum and maximum values). Calculations were made for the variables converted from raw values to sten scores (if they were required for a given test). The Mann-Whitney U test was used to check the differences between the two groups. Where more than two groups were compared, the Kruskal-Wallis (ANOVA) test was applied. If the differences occurred between groups in the ANOVA test, the Dunn-Bonferroni post hoc test value was calculated for identifying the groups which differed significantly. Interdependencies between the variables assuming continuous values were checked by calculating the correlation measure – Pearson’s r (for variables with normal distributions) or Spearman’s rank correlation coefficient being a nonparametric correspondent of Pearson’s r. The value of p<0.05 was adopted as statistically significant.