Factors affecting quality of life in patients on haemodialysis: a cross-sectional study from Palestine

A multicenter cross-sectional study was carried out from June 2014 to January 2015.

Patients were recruited from all dialysis centres in West Bank, Palestine. We collated related information about the distribution of the population from the Palestinian Central Bureau of Statistics and Ministry of Health [38].

The Healthcare sector in Palestine is primarily managed by the Government through the Palestinian Ministry of Health (PMOH). There are 10 functioning dialysis centres in West-Bank, Palestine. All the dialysis centres are on hospital campus and varies in size between one-machine to 32-machine centres. The PMOH runs nine out of the 10 available dialysis facilities [10]. At the time of the study, there were 740 dialysis patients served on 160 HD machines [38]. For the purpose of this study, sample size was detrmined using a Raosoft sample size calculator, which is a web-based calculator [39]. A sample size of 254 patients was considered to achieve a 5 % margin of error and a 95 % confidence level assuming that 50 % of patients answered each question correctly. The sample size was increased by 5–10 % to account for the non-response rate. Two hundred and seventy seven patients were selected using a convenience quota sampling method proportional to the number of patients in each dialysis centre. The inclusion criteria were as follows: (1) patients 18 years of age or older; (2) confirmed diagnosis of ESRD by medical file; and (3) on regular HD therapy for a minimum of 3 months prior to the interview. Patients were excluded if they lacked the mental or physical capacity to communicate with interviewer.

Data were collected using a questionnaire containing two sections, a socio-demographic and clinical history section and a validated Arabic version of HRQOL section [40]. Details regarding age, gender, body mass index (BMI) quartiles calculated from height and weight, educational level, household monthly income were obtained, residency, living status, smoking status [“light smoker”: (1 to 9 cigarettes/day), “moderate smoker”: (10 to 19 cigarettes/day), and “heavy smoker”: (≥20 cigarettes/day) [41]], marital status, occupation, dialysis vintage (length of time on dialysis treatment), average duration of dialysis session, total number of medications for chronic use, and the total number of chronic diseases. We categorised BMI as obese (BMI ≥ 30 kg/m²), overweight (BMI = 25 to <30 kg/m²), normal (BMI = 18.5 to <25 kg/m²), or underweight (BMI < 18.5 kg/m²) [42]. To determine the health status, the 5-level EuroQoL Group’s 5-dimension (EQ-5D-5L) questionnaire was used. The EQ-5D instrument was developed by the Euro QOL Group. The EQ-5D includes a 5-item descriptive system to calculate the EQ-5D index score and the EQ visual analogue scale (EQ-VAS) that allows the patients to judge their current health status during intradialysis from 0 to 100. The measuring principle of the instrument was described in detail in the previous works by the investigators [36, 37, 43]. The Arabic version of EQ-5D [40] was provided by using Euro QOL guidelines [44]. The study was registered with Euro QOL and permission was given for its use (ID: 8537, approval date: April 7, 2014).

Two hundred and seventy seven patients were recruited and interviewed face to face. We tried to make each interviewee feel as comfortable as possible. Face-to-face interview was used to provide researchers with an opportunity to collect as complete data as possible and to overcome non-response by those who cannot read. Interviews were performed by trained clinical pharmacy students. Data collection method was pre-tested to check for the clarity of questions in a pilot study of 16 patients was tested on eight medical files that were not included in the final anslysis. All the comments noted in the pilot study were taken into consideration and a modified questionnaire was reviewed by experts in the field of quality of live (QOL) to ensure content validity of data collection form in relations to factors that might be associated with QOL in ESRD population. The internal consistency of the EQ-5D instrument was found to be 0.84 which showed high reliability of the EQ-5D instrument.

The study protocol was approved by the Ethics Committee of An-Najah National University, and the local health authorities that had jurisdiction over the local study population. The interview content was described to respondents, and an informed verbal consent was obtained before the start of the interview.

Data were analysed using SPSS (SPSS Inc., Chicago, IL, USA) programme version 15. Results were reported as mean ± SDs or as frequencies and percentages or as a median with a range of values (lower-upper quartiles) wherever appropriate. Data that were not normally distributed were analysed using the Mann-Whitney U test or Kruskal-Wallis test according to the number of groups to compare. The Kolmogorov-Smirnov test was used to assess normality of distribution of data. The Pearson correlation coefficient was used to assess the correlation between the reported EQ-VAS scores and EQ-5D-5L index values. Multiple linear regression was carried out to identify factors that were significantly associated with HRQOL. Multiple linear regression was carried out to identify factors that were significantly associated with HRQOL (dependent factor). The independent factors were socio-demographic, and HD related clinical factors. A dummy coding of 0 and 1 was used to enter the nominal independent variables such as gender, BMI, educational level, residency, and occupation into the regression model. Variables with a p < 0.05 in univariate analysis were entered in the regression model. The significance level was predetermined at p level < of 0.05 for all tests. Variance inflation factors (VIF) and tolerance index were conducted to assess collinearity between independent variables. The internal consistency reliability of the study scale was assessed using Cronbach’s alpha values. EQ-5D was scored to calculate the index value using the value sets (weights) from the existing United Kingdom general population scoring algorithm (i.e. EQ-5D-5L Crosswalk Index Value Calculator [45]). We used the UK value set for three reasons; first, to present the health status as a continuous variable; second, due to absence of a locally or regionally appropriate set of values; and lastly to make the comparison more reasonable because most published studies at local or regional level used the UK value set as suggested by EuroQol Group the EQ-5D [12, 37, 46].

Two hundred and sixty-seven patients were participated in the current study giving response rate of 96 %. Overall, 139 (52.1 %) were male, and the mean (standard deviation) age was 53.3 (16.2) years. 177 patients (66.3 %) were on dialysis for less than four years. There were 204 patients (76.4 %) who were dialysed three times weekly among which 198 patients (74.2 %) stayed on dialysis three hours. The mean duration of disease was 3.4 ± 3.7 year. The majority of patients 197 (73.8 %) took their medication by themselves, 116 (43.4 %) had three or more chronic co-morbid diseases, and 222 (83.1 %) were on four or more chronic medications. The mean number of chronic co-morbid diseases was 2.4 ± 1.6 and the mean number of chronic medications was 6.5 ± 2.8. Overall, 52.7 % of study participants were either overweight or obese (28.1 % were overweight and 24.6 % were obese). Being obese was significantly more prevalent in females (14.8 %) as compared to males (9.8 %); (p value = 0.042). The socio-demographic and clinical characteristics of the study participants are displayed in Table 1.

The reported HRQOL as measured by mean EQ-5D-5L index value and EQ-VAS score was 0.37 ± 0.44 and 59.38 ± 45.39, respectively. There was a moderate positive correlation between the EQ-VAS and the EQ-5D-5L index value (r = 0.42, p < 0.001). The distribution of reported no problems across dimensions of QOL was as follows: mobility 73 (27.3 %), usual activities 100 (37.5 %), self-care 146 (54.7 %), pain/discomfort 68 (25.5 %) and anxiety/depression 94 (35.2 %); (Fig. 1). A total of 178 states of health were reported by the participants. We found that 17 (6.4 %) participants reported no problems for any dimension, and 9 (3.4 %) patients reported very severe difficulty for all five dimensions.

The median EQ-5D-5L index value was 0.41 (interquartile range: 0.06-0.77). Tables 2 showed that there were significant differences between participant groups according to age, BMI, education level, residency and total co-morbid disease, as well as gender, occupation, and total number of chronic medication (p-value < 0.05). No significant differences were found between participants according to income, living status, marital status, dialysis vintage, dialysis session duration, smoking status, and transplantation history.

The median EQ-VAS score was 50 (interquartile range: 50–70). As seen in Tables 3, there were significant differences between participant groups according to age and total co-morbid diseases, as well as gender, and total number of chronic medications (p-value < 0.05). Patients older than 60 years had a lower EQ-VAS score than those younger than 60. In addition, male gender was associated with higher EQ-VAS value compared to female. The study found that EQ-VAS score decreased as the total number of chronic medication increased and as illustrated in Table 3 increased co-morbid diseases had the lowest EQ-VAS score.

After adjustment for covariates, regression coefficients indicated significant associations between some of the independent variables and EQ-5D index score in comparison to a reference category for categorical variables or with one unit increase of a continuous variable. This model explained about 37 % of the variance in EQ-5D scores. As shown in Table 4, age, total number of chronic comorbid diseases and the total number of chronic medications were negatively associated with EQ-5D scores, whereas male gender, university education level and patients who live in village were positively associated with the EQ-5D scores. The range of VIF was from 1.015 to 1.465 which indicated absence of multicollinearity between independent variables.

This study had many strengths such as including a generalised sample of all HD centres in the West Bank, as well as conducting face-to-face interviews to obtain more complete data and high reliability of data collection. Furthermore, our study is the first study assessing HRQOL among ESRD patients in the West Bank and to the best of our knowledge is the first one in Palestine that used the EQ-5D scale as a measure. However, there were a number of limitations that need to be noted. First, the cross-sectional nature of this study makes it difficult to interpret any cause–effect relationship. Second, we used a convenience sampling technique that could decrease the generalisability of the results to other HD patients. Third, data were collected via a face-to-face interview which might have introduced interviewer’s bias in the results. Lastly, additional clinical variables such as albumin, calcium, and creatinine would help to get a more complete view of possible dialysis outcome factors related to HRQOL of HD patients.

The study protocol was approved by the Ethics Committee of An-Najah National University. The interview content was described to respondents, and an informed verbal consent was obtained before the start of the interview.

Not applicable.

All data supporting the study is presented in the manuscript or available upon request from the corresponding author of this manuscript, Zyoud S. H.