Introduction
Chronic kidney disease (CKD) is a major public health problem worldwide. The global prevalence of CKD has increased from 147.6 million in 1990 to 275.9 million in 2016 amounting to a 87% increase.1 CKD is very common in India but the true magnitude is not known. In a study by Apollo hospital Chennai the prevalence of impaired renal function(GFR<80ml) was seen in 8.6-13.9 per thousand population.2 A multistage cluster sampling done in south Delhi revealed the prevalence of CKD to be 0.76%.3 A study in a rural population in Shivamogga showed a prevalence of 6.3%.4 CKD is characterized by progressive and irreversible loss of kidney function and can lead to End stage renal disease(ESRD).5 Dialysis and kidney transplantation are the modalities of management of ESRD.Hemodialysis is most often used modality worldwide.6 The adequacy of dialysis for most Nephrologists refers to the biochemical outcome measures. Patients on maintenance hemodialysis suffer from many physical and psychological disabilities like fatigue,myalgia,sexual dysfunction, and depression.7 Studies have shown that from the patients perspective adequate dialysis is one that enables them to have a good quality time in their life8 Unfortunately we give little attention to these aspects of care. The World Health Organization (WHO) defines health as not merely the absence of disease or infirmity, but a state of complete physical, mental and social wellbeing.9 The concept of health related quality of life as an outcome measure in chronic disease has emerged over the past few decades .According to WHO quality of life(QoL) is defined as individuals perceptions of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns.10 In patients with a chronic disease such ESRD for which cure is not a realistic goal, maximizing functioning and well-being should be a primary objective of care. Quality of life has been shown to be less in all stages of CKD, however no association was detected between the stage of CKD and quality of life.11 There are plenty of studies on quality of life in patients on dialysis in western literature however there is no clear evidence regarding comparison of the same and its determinants in patients with advanced chronic kidney disease at stage 4 and 5.12 The culture and value systems among Indians is different from the west. Twice a week Hemodialysis is followed in most centers.13 Hence the western data is not applicable to Indian scenario. Therefore we decided to conduct a study to assess and compare the quality of life between patients with CKD stage 4 (pre dialysis) and patients on maintenance hemodialysis and also to see if there is any correlation between sociodemographic, clinical and biochemical parameters with perceived quality of life.
Materials and methods
This was a comparative cross-sectional study conducted at the dialysis and outpatient unit of our institute from January to December 2021. Patients were selected by convenience sampling method. The selected patients were divided into two groups namely Pre dialysis (CKD stage 4) and Dialysis group. Stage of CKD was defined as per NFK- DOQI guidelines.14 Glomerular filtration rate(GFR) was assessed using the MDRD formula. 15 Patients were included if they were more than 18 year old. Those included in the pre dialysis group had eGFR of 15-29 ml/min/1.73m2BSA (MDRD). Patients on maintenance hemodialysis for more than 3 months were included in the Dialysis group. Patients with major psychiatric disorders, drug/alcohol addiction, active malignancy, cirrhosis of liver, severe congestive heart failure (NYHA 4), and those hospitalized for treatment of any intercurrent illness were excluded.
Total of 100 each of pre dialysis and dialysis patients were enrolled. Written informed consent was obtained from each participant. The study was carried out in accordance with the standards of the declaration of Helsinki. Ethical clearance was obtained from hospital ethics committee. Patients were evaluated by detailed history and physical examination including socio demographic data, presence of Diabetes mellitus, use of erythropoietin, frequency and duration of dialysis. Hemoglobin, serum creatinine, serum albumin, calcium, phosphorus and body mass index were collected from patient medical records.
All the patients were provided with the SF- 36 questionnaire (Short form). The patients completed the answers to the questions on their own. For those who could not do the same due to inability to read or write the dialysis nurse / duty doctor would assist them by reading out the questions and documenting the answers.
SF-36 is a multi-purpose, short-form health survey with 36 questions. This instrument evaluates patients' perceptions of their health-related quality of life. It involves eight domains of health namely physical function, physical role, bodily pain, general health, vitality, social functioning, emotional role and mental health. These domains are divided in two component summaries: physical (physical functioning, physical role and bodily pain) and mental (social functioning, emotional role and mental health). The domains of general health and vitality are considered to belong to both component summaries. Scoring is by Likert method. Raw scores are linearly transformed to 0-100 scales. Higher scores indicate better health. 16
Statistical analysis
Chi square test for discrete variables and student t test for continuous variables were used for univariate analysis. ANOVA test was used to compare the means when there were more than two groups. The predictive ability of the factors which emerged after univariate analysis was confirmed by using logistic regression. All values were expressed as Mean
Results
Assessment of baseline characteristics (Table 1) showed that the pre dialysis group had significantly older population, and higher number of patients with type 2 diabetes. The hemoglobin level in the dialysis group was significantly lesser than pre dialysis group. All the other parameters were not significantly different between the two groups
Table 1
Baseline characteristics of pre dialysis and dialysis group
Table 2
Comparison of quality of life(QoL) between pre dialysis and dialysis patients
Table 3
Correlation of sociodemo graphic factors, Diabetes & BMI with QoL in dialysis group
Table 4
Correlation of erythropoietinuse, lab parameters, frequency of dialysis and duration of dialysis with quality of life in dialysis group
Table 5
Predictors of quality of lifein patients on Hemodialysis (logistic regression analysis)
Perceived quality of life was worse for dialysis patients compared to pre dialysis patients for the dimensions of physical functioning, body pain, vitality, social functioning, role emotional and mental health. The overall physical component summary score and mental component summary score of dialysis patients was also worse than the pre dialysis group. Similarly the total score was significantly lesser in dialysis group. (Table 2)
Among the patients in dialysis group age, sex, level of education, income, presence of type 2 diabetes and body mass index did not correlate with perceived quality of life. Use of erythropoietin, higher Hemoglobin, and higher Albumin levels, more frequent dialysis correlated with better physical component score, mental component summary score and total score. Total duration of dialysis, calcium and phosphorus levels had no impact on quality of life (Table 3, Table 4)
Logistic regression analysis was done with the factors which showed significant correlation with quality of life on univariate analysis. The independent predictors of higher Physical component summary scores and mental component summary scores in Dialysis group were Use of Erythropoietin, Higher albumin and more frequent dialysis. The independent predictors of higher Total SF36 scores were use of erythropoietin and higher albumin level (Table 5)
Discussion
This study showed that the perceived quality of life was worse for patients on hemodialysis when compared to pre dialysis patients in both the domains of physical and mental health. Poor quality of life has been associated with poor adherence to dialysis, 17 mortality and hospitalization.18 Tracking the quality of life of these patients should help the clinicians to provide an individualized care and can have the potential to improve outcomes. A recent study shows that exercise therapy improves physical function in CKD and has physiological and psychological impact.19 The correlation between stage of CKD and quality of life is controversial. One previous study failed to find any correlation. However this study shows a clear decline of quality of life from pre dialysis to dialysis stage. Aggarwal et al 20 also showed a clear progressive deterioration of quality of life with progression of CKD.
Mere knowledge of quality of life scores alone is not sufficient. We need to know the factors associated with it so that corrective measures are taken. We attempted to do the same by exploring the correlation between quality of life and sociodemographic, clinical, and biochemical parameters. Univariate analysis showed significant association between use of erythropoietin, higher Hemoglobin, higher Albumin levels and more frequent dialysis with better quality of life. However Logistic regression analysis showed that use of erythropoietin, higher albumin levels and more frequent dialysis were the independent predictors of better PCS and MCS scores. Dialysis patients treated with erythropoietin show improved exercise tolerance and physical function.21 This explains the higher PCS and MCS scores. Higher hemoglobin emerged as significant factor on univariate analysis but failed to emerge as significant on logistic regression suggesting that higher hemoglobin values were dependent on erythropoietin use. The major limitation for use of erythropoietin in developing countries is cost. A reduction of cost of these medications should make them more easily accessible to patients. Albumin is a marker of nutritional status and a lower level of the same suggests malnutrition. Our finding of low albumin being associated with poor quality of life is in concordance with studies in the past.22 Increased inter dialytic interval leads to fluid overload causing shortness of breath, pulmonary edema ,gastrointestinal edema and loss of appetite.23 This necessitates large volume removal by ultrafiltration causing symptomatic hypotensive episodes with nausea ,cramps and vomiting. Prolonged inter dialytic interval can also result in dialysis disequilibrium syndrome with headache, confusion, seizure and dizziness.24 More frequent dialysis means shorter inter dialytic interval thereby can alleviate these complications. This is possibly the cause of improved quality of life we observed in patients who underwent more frequent hemodialysis (twice and thrice weekly). Studies in the past have shown that increased age is associated with poor quality of life on hemodialysis.25 However we failed to find such an association. Older adult’s expectations of physical strength may be lesser when compared to younger population. They may have unique life experiences and spirituality which may alter their expectations. These could be the possible reasons why we did not observe any decline in quality of life in older patients. Gender did not affect the quality of life in our study. Previous studies have shown that men had better QoL than women,26 females had better25 or equal.27 Unlike previous studies25 we did not observe any correlation between education level or socioeconomic status with QoL. A number of patients undergoing hemodialysis at our center had their dialysis cost borne by Employee state insurance which can explain the finding. Similar to some previous studies25 we did not find any correlation of quality of life with diabetes mellitus. High and low serum phosphorus and high calcium have been shown to be associated with a poor quality of life.28, 29 The mean calcium and phosphorus levels of our patients were well within the recommended levels30 thereby resulting in our observation of no correlation between these parameters and Qol.
Cross sectional studies capture QoL at a given point of time and fail to document changes over a period of time. This is a limitation of this study. Since patients included were from only one center our findings may not be generalizable. Follow up and repeated assessments and multicenter studies are required to obtain better information
