Health-related quality of life of patients undergoing haemodialysis therapy in Dar es Salaam, Tanzania

educational level, employment status and income. Clinical factors such as the duration of dialysis, comorbidities, and the adequacy of dialysis have also been shown to influence the HRQOL score [5–7]. There are fewer studies on HRQOL among haemodialysis patients in LMICs. Most have reported similar findings to those reported globally, with lower HRQOL compared ABSTRACT Background: Patients with kidney failure on maintenance haemodialysis therapy have a lower health-related quality of life (HRQOL) than matched controls without kidney failure. HRQOL is an important predictor of clinical outcomes among patients with kidney failure, yet there is a paucity of such data in Tanzania. We determined HRQOL among Tanzanian patients with kidney failure receiving maintenance haemodialysis therapy. Methods: A cross-sectional study was conducted at Muhimbili National Hospital (MNH) in Dar es Salaam, from June to October 2020. MNH is a tertiary public sector hospital with 50 dialysis machines. Here, the Kidney Disease Quality of Life Short Form-36 questionnaire was used to assess HRQOL in 209 patients (69% male; mean age 51.9 ± 13.5 years). Their scores were categorized as low if the overall mean was ≤50, and as high if the score was >50. Factors associated with lower HRQOL were identified using multivariate logistic regression. Results: Overall HRQOL was low (mean score 48.9 ±13.9) and the factors associated with the scores recorded were having less than three haemodialysis treatment sessions per week [adjusted odds ratio (OR) 1.356, 95% CI 0.707–2.254] and urea reduction ratio <65% (OR 2.229, 95% CI 1.238–3.014). Conclusions: The overall HRQOL of patients undergoing haemodialysis was low. Receiving less than three haemodialysis sessions per week and having a urea reduction ratio of less than 65% were associated with lower scores. These findings underscore the importance of providing adequate haemodialysis treatment in improving the quality of life of patients with kidney failure.


INTRODUCTION
Chronic kidney disease (CKD) is among the fastestgrowing public health problems worldwide, which is increasing in terms of incidence and prevalence.The global prevalence is estimated to be around 10-13% and similar rates are reported in Africa.Patients with kidney failure require kidney replacement therapy in the form of haemodialysis (HD), peritoneal dialysis (PD) or transplantation.In many low-and middle-income countries (LMICs), conservative and supportive kidney care and chronic haemodialysis are the main management strategies for patients with kidney failure [1][2][3].
Patients with kidney failure have lower health-related quality of life (HRQOL) scores than the general popula-tion, particularly in the physical and emotional domains [4].In high-income countries, HRQOL of patients on haemodialysis has been extensively studied, and assessment of quality of life is becoming routine.The factors which have an impact on HRQOL include age, sex, educational level, employment status and income.Clinical factors such as the duration of dialysis, comorbidities, and the adequacy of dialysis have also been shown to influence the HRQOL score [5][6][7].
There are fewer studies on HRQOL among haemodialysis patients in LMICs.Most have reported similar findings to those reported globally, with lower HRQOL compared to the general population.However, there is a considerable heterogeneity in the predictors of HRQOL, and the factors that are associated with this measure vary across different populations and settings [8][9][10][11].
In Tanzania, there are currently only two transplant centres, each performing fewer than 10 kidney transplants per year, and most patients with kidney failure who start KRT receive chronic haemodialysis.HRQOL has not yet been recorded in Tanzanian patients; the study reported here aimed to assess HRQOL and explore factors associated with it in our setting.

METHODS
A cross-sectional study to assess HRQOL scores was conducted from June to October 2020 among patients on maintenance haemodialysis at the haemodialysis unit of Muhimbili National Hospital (MNH), a 1500-bed tertiarylevel public health facility in Dar es Salaam, Tanzania, which has approximately 50 haemodialysis machines.Around half the patients are covered by health insurance, with government health insurance accounting for almost two-thirds of this group, whereas the remainder pay out-of-pocket for haemodialysis treatments.Approximately half the patients complete only twice-weekly sessions, due to financial constraints.Most use high-flux dialyzers, with each treatment session lasting four hours.Temporary (non-tunnelled) dialysis catheters are used as the usual vascular access, and blood flow rates of above 250 mL/min are not often achieved.
We enrolled all patients aged 18 years or above, who had been stable on chronic haemodialysis for at least three months and had provided written informed consent.Those with cognitive impairment were excluded.
For each participant, we documented age, sex, level of education, marital status, occupation and health insurance status.Clinical and laboratory data such as duration on haemodialysis, presence of comorbidities (such as hypertension, diabetes mellitus, HIV infection, stroke, heart failure and cancer), vascular access, haemoglobin, serum albumin and creatinine were also extracted from hospital records.Blood was collected for pre-and post-dialysis urea concentrations and used for the assessment of dialysis adequacy by calculating the urea reduction ratio (URR), with ≥65% considered adequate [12].
To assess HRQOL, the Kidney Disease Quality of Life Short Form-36 (KDQOL-36™) was used.This instrument consists of 36 items, divided in two main categories: the first 12 items are generic components, measuring patients' perceptions of their physical and mental functioning and the remaining 24 items are kidney disease targeted items (KDCS).The generic component section consists of two subscales, the physical health composite score (PCS) and the mental health composite score (MCS).The kidney disease-specific section (KDCS) has three subscales: burden of kidney disease (BKD), symptoms and problems of kidney disease (SPKD) and effects of kidney disease (EKD) on daily life [13].For our study, the KDQOL-36™ tool was translated from English into Swahili and back translated by a professional translator for consistency and validity and assessed by two experts in the field of nephrology for clarity and comprehensiveness.It was piloted among 15 patients on maintenance haemodialysis and found to be satisfactory; no further modifications were needed.The scoring was uniform across the English and Swahili versions.The tool was administered during haemodialysis sessions, using an interview-based approach as some of the participants could neither read nor write.
Data entry and statistical analysis were performed using SPSS version 25.Cronbach's alpha for the KDQOL-36™ tool was 0.845, indicating good internal consistency.Descriptive statistics are reported using mean ± standard deviation (SD), median and interquartile range (IQR), or proportions, as appropriate.The overall HRQOL and five subscales of the KDQOL-36™ (PCS, MCS, BKD, SPKD and EKD) are presented in terms of mean score ± SD.Overall mean scores of ≤50 and >50 were considered as lower and higher HRQOL, respectively.Factors potentially associated with HRQOL are reported using adjusted odds ratios (OR) with 95% confidence intervals (CI).Variables with P values <0.2 in bivariate analysis and those with clinical relevance were entered into a multivariate logistic regression.A P value of <0.05 was considered statistically significant.

Quality of life of Tanzanian patients on dialysis
The mean HRQOL score was 48.9 (±13.8) with half of the study participants scoring below 50.Among the five subscales, the lowest mean score (27.5 ± 17.5) was on burden of disease, in terms of which 91% of patients scored below 50 (Table 3).
Variables with P values <0.2 in the bivariate analysis and those known to have clinical significance for quality of life were included in the multivariate analysis.They included age, sex, employment status, frequency of haemodialysis sessions, vascular access type, duration of haemodialysis, insurance status, presence of comorbid conditions and dialysis adequacy.On multivariate analysis, having fewer than three sessions of haemodialysis per week (OR 1.356, 95% CI 0.707-2.254)and URR <65% (OR 2.229, 95% CI 1.238-3.014)were associated with lower HRQOL (Table 4).

DISCUSSION
Our study provides valuable insights into the status of HRQOL scores among Tanzanian patients with kidney failure who are treated with haemodialysis.Half of our participants had a mean HRQOL score below 50%, highlighting the significant burden of kidney failure and its treatment on their overall quality of life.The lower HRQOL scores may be due to a combination of physical, emotional and lifestyle factors associated with kidney failure and haemodialysis [9].Patients on haemodialysis are also at risk of illnesses such as depression, anxiety, and cardiovascular disease, which can negatively affect their HRQOL [10].Our findings are consistent with studies conducted in similar settings [8][9][10].
We found that the physical composite score (PCS) was lower than the mental composite score (MCS), in line with results from other studies [10,14].This could be related to the high prevalence of comorbidities such as diabetes and hypertension in this group of patients [4].In contrast, MCS scores may have been higher due to the good psychosocial support provided by dialysis nurses and family members, and the regular contact with healthcare providers.The findings suggest that, compared to physical health, the mental health of patients with kidney failure is well preserved [14].

Quality of life of Tanzanian patients on dialysis
Regarding kidney disease-targeted components, we found that the symptoms of the kidney disease subscale had the highest score, which is consistent with findings from other studies [9,15].The burden of disease subscale had the lowest score with over 90% of participants scoring below 50 points.These findings are in line with those of previous studies [8,16,17] and highlight the fact that patients with kidney failure experience a high burden of disease, due to physical and emotional symptoms, and treatment-related complications.
Haemodialysis is the most common treatment for patients with kidney failure worldwide and is usually performed on three days per week, for 3 to 5 hours per session [18].In Tanzania, patients who do not have insurance and pay out-

Table 1 .
Sociodemographic characteristics of participants.

Table 2 .
Clinical and laboratory characteristics of participants.

Table 3 .
Health-related quality of life and subscales scores (N = 209).

Table 4 .
Multivariate analysis of factors associated with HRQOL among haemodialysis patients.
Abbreviations: OR, odds ratio; HRQOL, health-related quality of life.