Nutritional status of chronic kidney disease patients undergoing hemodialysis in Colombo, Sri Lanka

Introduction: Malnutrition is a common condition among patients receiving hemodialysis and one of the principal indicators of mortality and morbidity. Objectives: The main aim of the study was to assess the nutritional status of hemodialysis recipients. Methods: A cross-sectional study was conducted on fifty-five patients in two nephrology clinics in Colombo. Data were collected under four categories; an interviewer-administered questionnaire, anthropometric measurements, biochemical investigations and derived calculations. Urea reduction ratio and Kt/V were calculated to assess the dialysis efficiency. Nutritional Risk Index was employed to evaluate the malnutrition risk. Results: In the study population, 70.9% were males and mean age, mean dialysis duration were recorded as 56.05±13.16 years and 13±12 months respectively. According to BMI, 10.9% of the patients were underweight, 38.2%; normal, 14.5%; overweight and 36.4% were obese. Low levels of serum albumin, total protein, iron and hemoglobin were reported among 30.9%, 14.5%, 41.8% and 89.1% of patients respectively. More than 50% of the population had an increased CRP level, depicting an inflammatory reaction. Mean URR and Kt/V of the population were 65.8±9.6% and 1.3±0.3 respectively, which were above the recommended level. Malnutrition risk was negatively correlated with serum total calcium level (r=-0.49, p<0.001), total protein level (r=-0.415, p<0.05), dialysis duration (r=-0.351, p<0.05), diastolic blood pressure (r=-0.35, p<0.05) and MUAC


Introduction
Chronic kidney disease (CKD) is a principal factor of mortality, disability, and medical expenditures, making it one of the most critical public health problems today.The number of people with CKD is rising at a rate of 7 percent annually over the world [1].According to the National Kidney Foundation, CKD is responsible for much more fatalities than breast or prostate cancer [2].Among the many factors that can lead to kidney failure, hypertension, glomerulonephritis, and diabetes mellitus are among the prominent factors.Nearly three-quarters (75%) of all cases in adults are attributable to them [3,4].Despite the reduction in incidence of most other chronic diseases during the previous several years, it is expected that CKD will grow to the fifth most prevalent reason of years of life lost worldwide by 2040 [5].
CKD can advance to end-stage renal disease (ESRD), in which the kidneys cease functioning entirely, and ultimately causes death [6].To extend the lives of patients with ESRD, kidney replacement therapy, such as dialysis (Key words: chronic kidney disease, hemodialysis, malnutrition, nutritional risk index) (r=-0.332,p<0.05) and positively correlated with absolute lymphocyte count (r=0.332,p<0.05).

Conclusion:
Majority of the patients had an efficient dialysis session.High, moderate and low risk of malnutrition were analyzed as 7.3%, 29.1% and 63.6%.In a binomial logistic regression, total calcium level (p<0.001,Exp(B); 0.027) and appetite of patients (p=0.04,Exp(B);13.816)were identified as strong predictors of malnutrition risk.

Original article
or a renal transplant, must be recommended [7].As of 2017, it was estimated that 3.9 million people with renal failure received kidney replacement therapy (KRT).In terms of frequency, hemodialysis (HD) accounts for around 69% of all KRT and 89% of all dialysis performed worldwide.In a study that included participants from 182 countries, Htay et al. (2021) determined that the median HD use per million people (pmp) was 298.4 [5,8] .
However, malnutrition is a major issue for patients on hemodialysis, with a frequency of 28-54% worldwide and an increased risk of mortality of 1.61-4.08odds [9,10].Malnutrition-related morbidity has severe effects on the quality of life (QoL), frailty, infection vulnerability, and survival in these individuals [9,11] .Malnutrition in dialysis patients develops differently than in patients with acute illnesses or those in critical care.It results from the progressive nature of CKD, the development of a lowprotein diet to decrease CKD progression, and dialysis related factors [9].Therefore, monitoring hemodialysis recipients' nutritional condition on a consistent basis is essential for ensuring their continued health and wellbeing [12].
Hemodialysis is the main and most widely available type of renal replacement therapy available for ESRD patients in Sri Lanka [13].However, the nutritional health of patients on hemodialysis has not been the main focus of many documented research or investigation in Sri Lanka.Consequently, the main intention of this research was to examine the nutritional standing and occurrence of malnutrition among the hemodialysis population in Sri Lanka.The efficiency of dialysis, presence of infections, and how these factors affected the patients' nutritional status were also evaluated.The nutrition risk index (NRI) was utilized to assess and categorize the patients' risk for malnutrition [14].

Study design
A cross-sectional study was conducted for a period of six months from October 2021 to April 2022, including all the patients registered for hemodialysis under the supervision of a consultant nephrologist.Fifty-five patients that underwent regular hemodialysis and above the age of eighteen were included in the study.Sample size was calculated using a relevant scientific equation [15].The prevalence of ESRD patients needed for the calculation has been taken as 3% [13,16] ).

Data collection tools
A questionnaire administered by an interviewer, anthropometrics, laboratory tests, and derived computations were used to collect data.
Questionnaire was used to collect; (1) demographic information (2) dialysis information (like dialysis vintage, dialysis sessions per week, access, etc.) and (3) nutrition related information (which included 24-hour food recall, daily water/fluid intake etc.).Reponses for the questionnaire were recorded during the 4-hour dialysis session.Some anthropometric measurements including; pre and post dialysis weight, body mass index (BMI), mid upper arm circumference (MUAC), skinfold thickness etc. were taken.MUAC (cut off >21 cm) [17] was measured using a non-stretchable measuring tape (cm) and skinfold thickness was measured using slim guide skinfold caliper (mm) [TSFT cutoff: male=12.5 cm, female=16.5cm][17,18].MAMC [cutoff: in male=25.3mm,female=23.2mm][17,18] was calculated using the following standard equation [MAMC (cm)=MUAC (cm) -[3.14xTSFT (mm)] [19].Body fat percentage of patients were also calculated according to Durnin and Womesely data.The body weight of patients was measured both before and after the dialysis session.All the other anthropometric measurements were taken after the dialysis session.
A series of laboratory investigations were performed from three blood samples collected from each patient (EDTA and serum specimen 30 minutes before dialysis and another serum specimen 30 minutes after the dialysis session).Hematological investigations were performed in Mindray BC -6800, 5 -part analyzer and biochemical investigations were conducted in Abbott Architect Plus c4000 analyzer.Hemoglobin concentration (Colourimetric method), absolute neutrophil count and absolute lymphocyte count (light scatter method) were measured from an EDTA sample collected before dialysis.Serum creatinine [Alkaline picrate (kinetic) method], serum urea [Urease-glutamate Dehydrogenase (UV) method] and serum electrolytes -Na, K (Ion selective electrode method) were measured in both pre and post dialysis serum samples.Series of laboratory investigations including serum albumin (Bromocresol green method), serum total protein (Biuret method), serum total cholesterol [Cholesterol-oxidase peroxidase method], serum iron [Ferrizone (colourimetric) method], serum total calcium (Arsenazo III method), serum phosphorus [Phosphomolybdate (colourimetric) method], and serum CRP (Immuno-turbidometric method) were conducted from a post dialysis serum sample to evaluate the nutritional status of patients.URR and Kt/V were used to determine the effectiveness of dialysis sessions.Nutritional risk index (NRI) [14] was utilized to estimate the population's vulnerability to malnutrition and it was calculated from the equation; NRI = Low BMI + Low serum albumin + Abnormal serum total cholesterol level + Low serum creatinine level.
A score was calculated according to the relevant criteria and the patients were categorized as; Low risk, Medium risk and High risk, with respect to the possibility for malnourishment [14].

Data analysis
SPSS version 28 was used to analyse the data in accordance with the objectives of the study.Each piece of data was analysed to generate descriptive statistics.The paired sample t-test, Chi-Square test, and Pearson Correlation were used to compare data collected prior to and after dialysis, to examine associations between categorical variables, and to evaluate correlations between variables, respectively.Binomial logistic regression was used to identify predictors of malnutrition risk.

Descriptive statistics
Data were collected from 55 patients that undergo maintenance hemodialysis.The demographic and anthropometric results of the study population are summarized under Table 1.The study population consisted of 39 males (70.9%) and 16 females (29.1%).Average age of the study group was 56±13 years and majority of patients were reported from the category >60 years of age (Table 1).
Results related to dialysis details and clinical history of the patients are presented in Table 2. Mean dialysis duration was calculated as 13 ± 12 months.43.6% -(24) of the participants were included in the category, 6 months to < 2 years.In terms of URR and Kt/V, 60% and 74.5% of the population had an efficient dialysis session respectively.Most prevalent side effects were itching (61.8%) and fluid overload (58.2%), common complications during hemodialysis were hypotension (54.5%) and cramps (45.5%).Appetite of the patients on days of hemodialysis sessions were recorded.According to the data gathered from 24-hour food recall, 67.3% of individuals were following the prescribed dietary patterns (Table 2).
Results of the Laboratory investigations and the malnutrition risk among the study population in terms of the NRI are presented in the following table.36.4% patients had a moderate to high risk of malnutrition (Table 3).Several anthropometric parameters and laboratory investigations were performed both before and after dialysis to determine the effect of dialysis procedure on the factors under study.According to paired sample t-test results, there was a statistically significant variation between the prior and subsequent values of most of the tested parameters (Confidence interval 95%) (Table 4).

Associations among categorical variables:
(Confidence interval 95%) High CRP level was detected in patients below 56 years (p=0.034).Patients who had underwent dialysis for ≥12 months had a high absolute neutrophil count (p=0.025).Furthermore, patients engaged in dialysis for ≥12 months had a high neutrophil to lymphocyte ratio (p=0.001).
Greater dialysis efficiency (as measured by URR and Kt/V) was related to older age (p=0.007),state of employment (p=0.013), and normal blood total protein concentration (p=0.029).URR was also related to serum CRP concentration (p=0.039).The majority of patients with ineffective dialysis (URR) reported elevated CRP levels.

Discussion
Malnutrition has been identified as a widespread health problem among hemodialysis population along with being among the leading causes of mortality and morbidity [20,21].However, available evidence and data regarding this issue in the Sri Lankan context are inadequate.Thus, the main aim of this research was to examine the nutritional health of patients undergoing hemodialysis using the nutritional risk index [14], laboratory investigations and anthropometric measurements.The current investigation also assessed the dialysis efficiency of participants using URR and Kt/V.
The recommended level of interdialytic weight gain to be maintained is < 4% -4.5% of dry weight of patients [22].Among the recruited group of patients, most had a weight gain greater than the recommended level to be maintained.As a result, the blood pressure of majority of the patients were greater than the recommended level of; pre dialysis systolic blood pressure: 130-159 mmHg and post dialysis systolic blood pressure: 120-139 mm Hg [23].
It was discovered that the risk of malnutrition among majority of the current study population was low (63.6%) and 29.1% were identified with moderate risk and only 7.3% with high risk.Since the study sample was selected from two hospitals in Colombo, most patients were economically stable to meet their nutritional requirements.Furthermore, according to the study findings majority of them (67.3%) had followed the instructed food patten by the nephrologists to maintain the quality of life.Since 90.9% of the participants were married and 94.5% of the population were living with their families, patients were gaining much attention and care from the family members and this also may have an effect on the low malnutrition risk in the population [1].

Original article
There was a clear relationship between the CRP level and age of patients among the individuals included in the study; a high CRP level was common among patients younger than 56 years.Most of the patients below 56 years were engaged in an occupation.Thus, they have a higher vulnerability for infection than those who are retired and staying at home.In addition, absolute neutrophil count, absolute lymphocyte count, and neutrophil to lymphocyte ratio were evaluated as infection/inflammation indicators [24].The presence of a high absolute neutrophil count, a low lymphocyte count, and a high neutrophil-tolymphocyte ratio in patients who had undergone hemodialysis for 12 months or more suggests that these patients are more susceptible to infection.Moreover, it was identified that most patients who were <56 years and employed had an inefficient hemodialysis session compared to others, according to the values of URR and Kt/V [25].It can be due to the generation of more waste products in the body with the use of more energy on work.Patients with a high CRP level also showed an inefficient dialysis, emphasizing that the inflammation status of the patients affects the dialysis adequacy [26].Furthermore, it was recognized that risk of malnutrition had a strong negative correlation with the dialysis duration, reflecting that in comparison to the patients who initiated hemodialysis recently, patients who had engaged in dialysis for about 2 years had a lower risk of malnutrition.This phenomenon was also highlighted in the research conducted by Sahathevan, et al. (2020) [9].The analysis by Azzeh, et al. (2022) [27] indicated that patients with a dialysis vintage more than 4 years had a high prevalence of malnutrition.Finally, binomial logistic regression analysis in the present study revealed that patients' appetite and serum total calcium levels were strong predictors of malnutrition in the hemodialysis population.

Limitations
The study sample was limited to fifty-five patients because it was unable to access a larger sample size due to the COVID-19 restrictions prevailed in the country.Moreover, the study was conducted only in one district of the country, thus the diversity of the study sample could have been a limitation in this research.

Conclusion
The current study identified that a significant proportion (36.4%) of the hemodialysis population has a moderate to high risk of malnutrition.Serum total calcium level and appetite of patients were recognized as significant predictors of malnutrition risk.Therefore, this study implicates the crucial requirement to screen the nutritional condition of hemodialysis recipients and to implement management policies to enhance the nutrition and quality of life of the patients.Further studies need to be conducted to investigate the influence of nutritional status on the morbidity and mortality of patients and to identify remedial clinical therapies to upgrade the nutrition, quality of life and the survival of patients on hemodialysis.We expect to conduct a large-scale multicenter study to perform an overall analysis of main medical concerns of hemodialysis recipients including nutritional status, dialysis adequacy and risk factors of mortality.