Investigating Physical and Nutritional Changes During Prolonged Intermittent Fasting in Hemodialysis Patients: A
Prospective Cohort Study
Nurul Iman Hafizah Adanan, BSc,
*Mohamad Syafiq Md Ali, BSc,
*Jun Hao Lim, BSc,
*Nor Fadhlina Zakaria, MD, MMed,† Christopher Thiam Seong Lim, MBBch, MRCP, FAMS, FRCP,†
Rosnawati Yahya, MBChB, MRCP, FRCP,‡ Abdul Halim Abdul Gafor, MBBS, MMed,§
Tilakavati Karupaiah, PhD, APD, { and Zulfitri ‘Azuan Mat Daud, PhD, RDN
*Objective:Studies investigating the health effects of prolonged intermittent fasting during Ramadan among Muslim patients on he- modialysis (HD) are limited and reported heterogeneous findings. This study aimed to evaluate the effects of intermittent fasting during Ramadan on nutritional and functional status of patients on maintenance HD.
Design and Methods:This was a 12-week, multicenter, prospective observational study. The study setting included three HD centers.
Adult Muslim patients, who were undergoing HD session thrice weekly and planned to fast during Ramadan, were screened for eligibility and recruited. Nutritional and functional status assessments were carried out 2 weeks before (V0), at the fourth week of Ramadan (V1), and 4 weeks after Ramadan (V2). Nutritional status parameters included anthropometry (body mass index, interdialytic weight gain, waist circumference), body composition (mid-arm circumference, triceps skinfold, body fat percentage), blood biochemistry (albumin, renal profile, lipid profile, and inflammatory markers), blood pressure, dietary intake, and handgrip strength. Changes in nutritional and functional status parameters across study timepoints were analyzed using repeated-measures analysis of variance.
Results:A total of 87 patients completed the study, with 68 patients (78.2%) reporting fasting$20 days. Ramadan fasting led to sig- nificant reductions (allP,.05) in body mass index, interdialytic weight gain, waist circumference, mid-arm circumference, fat tissue mass, and body fat percentage, but these were not accompanied by any significant change in lean tissue mass (P..05). Significant improvement was observed in serum phosphate levels, but serum albumin, urea, and creatinine were also reduced significantly during Ramadan (P,.05). There were no significant changes in lipid profile and inflammatory markers. Interestingly, energy and protein intakes remain unchanged during Ramadan. Handgrip strength improved significantly during Ramadan and further improved after Ramadan.
Conclusion:Intermittent Ramadan fasting leads to temporary changes in nutritional status parameters and poses nondetrimental nutritional risk for patients on maintenance HD.
Ó2019 by the National Kidney Foundation, Inc. All rights reserved.
Introduction
T
HE PERIOD OF Ramadan which falls on the ninth month of the Islamic calendar calls for consecutive fasting during daylight hours which extends for 4 weeks.The duration of daylight fasting varies according to the time of the year in which Ramadan falls. In some parts of the world, daylight can be as long as 20 hours in the peak of summer, whereas countries nearer to the tropics and
equator have fasting duration of typically about 13 hours.1 During fasting, all Muslims are prohibited from eating, drinking, taking medication, and engaging in sexual activ- ities.2This form of intermittent fasting during Ramadan is a tenet of Islam followed by all healthy Muslims barring pre- pubertal children, women during menstruation and preg- nancy, the elderly, and those who are acutely or chronically ill. With regard to chronic kidney disease
*Department of Nutrition and Dietetics, Faculty of Medicine and Health Sci- ences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
†Deparment of Medicine, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
‡Department of Nephrology, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia.
§Department of Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
{School of BioSciences, Taylor’s University, Subang Jaya, Selangor, Malaysia.
Support: This study was funded by Universiti Putra Malaysia internal grant (GP-IPS: 9615300). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Financial Disclosure: The authors declare that they have no relevant financial interests.
Address correspondence to Zulfitri ‘Azuan Mat Daud, PhD, RDN, Depart- ment of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Uni- versiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.E-mail:
Ó2019 by the National Kidney Foundation, Inc. All rights reserved.
1051-2276/$36.00
https://doi.org/10.1053/j.jrn.2019.06.003
Journal of Renal Nutrition,Vol-, No-(-), 2019: pp e1-e12 e1
(CKD), there are reports that patients on maintenance he- modialysis (HD) do actually observe fasting to express reli- gious adherence.3
As Ramadan fasting imposes lifestyle shifts related to change in meal timing, frequency, availability of food, and food culture,4it would be expected that dietary and fluid intake regulation may lead to deterioration in nutritional and health status of patients with CKD who observe fast- ing.5 Prolonged intermittent fasting lasting from 12 to 22 hours per day extended for 4 weeks may cause a chronic suboptimal energy intake which predisposes to higher risk for malnutrition.6A Saudi Arabia study reported the risk of dehydration during long fasting hours and subsequent fluid overload by sudden increases in fluid intake after breaking fast.6Apart from this, Ramadan fasting has been associated with reduced body weight but improved serum albumin and phosphate levels in a Malaysian HD population (n537) which may indicate improvement in fluid control rather than nutrition depletion, although there was no di- etary intake assessment reported for the study.7However, a Saudi Arabia HD cohort of 6-week assessment reported no differences in metabolic profile before and during Ramadan despite the changes in meal frequency and life- style behavior.8All these studies highlight confounding fac- tors such as variations in daily fasting time, patient demographics, hydration status, and diversity in dietary habits and food culture which indicate the lack of under- standing on the true impact of the intermittent fasting during Ramadan on the nutritional status of patients on HD.9The question raised is whether intermittent fasting as practiced during Ramadan leads to a deterioration in the physical status of the patient due to abnormal food intake patterns in patients on maintenance HD. There is scarcity of the literature reporting the nutritional status of these patients in hot climates. Furthermore, there are no clear dietary guidelines which inform on guiding such patients who wish to practice intermittent fasting for a lengthy period. Given these gaps, this prospective cohort study investigated the effects of intermittent fasting during Ramadan on the nutritional and functional status among Muslim patients undergoing chronic HD in an equatorial climate country.
Methods
Study Design and Patient Recruitment
This was a multicentered study involving Muslim patients recruited from 3 HD centers in the Klang Valley, Malaysia, who were prospectively followed up over a period of 12 weeks from May 2018 to July 2018.
Inclusion criteria were patients who were Muslims, planned to follow intermittent fasting during Ramadan, aged above 18 years, on maintenance HD for at least 3 months, and compliant to the study protocol. On the other hand, patients with poor adherence to HD treatment and having physical and mental impairment or terminal illnesses were excluded from the study.
Data collection was carried out at three timepoints:
2 weeks before Ramadan (V0), at the fourth week of Ramadan (V1), and 4 weeks after Ramadan (V2). This study received ethical approval from the Medical Research and Ethics Committee, Ministry of Health, Malaysia (ID: NMRR-17-2756-37435).
Sociodemographic Factors and Medical History
Data on age, gender, education level, and medical history including cause of renal failure and underlying diseases were obtained from patient medical records.
Nutritional Status Assessment
Anthropometry and Body Composition Measurements
Weight, height, mid-arm circumference (MAC), tri- ceps skinfold (TSF), and waist circumference (WC) were measured by a trained dietitian following the stan- dardized protocol as per guidelines of the International Society for the Advancement of Kinanthropometry10as utilized in other studies on HD populations.11 Body weight was performed before and after dialysis using a digital weighing scale (SECA, Model 220; SECA, Ger- many). Body mass index (BMI) was derived using post- dialytic weight divided by height squared (in kg/m2; weight [kg]/height [m2]). Interdialytic weight gain (IDWG) was defined as the difference between predia- lytic weight and weight at the end of previous dialysis session,12 and this was derived as an average per week covering V0, V1, and V2 periods of the 12-week study, from each patient’s weight records. MAC and WC were measured using a nonstretchable Luftkin tape (Apex Tool Group, LLC, NC), and a Harpenden skinfold caliper (HSK-BI, British Indicators, West Sussex, UK) was used to measure TSF. These measurements were conducted on the arm without vascular access. The following equation was used to calculate mid-arm muscle circumference (MAMC) and mid-arm muscle area (MAMA)13:
MAMCðcmÞ5MACðcmÞ2½TSFðcmÞ3p
MAMAðcm2Þ5MAMCðcmÞ2=4p210:00ðf or menÞor 6:5ðf or womenÞ
Body composition was assessed using a portable whole- body composition monitor bioimpedance spectroscope (Body Composition Monitor, Fresenius Medical Care) and as per the protocol described by other studies.14The physiological differences in terms of distribution and amount of fluid (extracellular, intracellular, and total body water) determine lean tissue mass (LTM), overhydration, and fat mass.15
Biochemical Assessment
Analyses of renal profile, lipid profile, serum albumin, and high-sensitivity C-reactive protein using an automated clinical analyzer (Cobas 6000; Roche, Germany), were car- ried out as per standard protocol published elsewhere.16In addition, normalized protein catabolic rate (nPCR) as a surrogate biochemistry marker to evaluate dietary protein intake was calculated using the formula reported elsewhere.17
Blood Pressure Assessment
Systolic and diastolic blood pressure were recorded before dialysis using an automatic blood pressure monitor (Omron HEM-7120; Kyoto, Japan). Subjects were asked to refrain from physical exercise for at least 30 minutes before measurement and then asked to sit for at least 5 mi- nutes without smoking, meal, caffeine intake before taking measurement. Before measurement, subjects were seated in a quiet room with back supported and leg uncrossed, silent and relaxed. The cuff bladder was then placed at heart level before measurement was initiated.18
Dietary Assessment
Three days of dietary recalls (3DDR) were collected which included a dialysis day, nondialysis day, and a week- end day to calculate intakes of energy, macronutrients (car- bohydrate, protein, fat), micronutrients (sodium, potassium, phosphate), and fluid for each patient. This approach has also been used in previous studies by our group.19These diet recalls were then analyzed using the Nutritionist ProTM 2.2.16 software (First Databank Inc, 2004) with reference to the national food composition database.20Dietary energy and protein intakes were inter- preted in terms of patients’ ideal body weight. The ratio of the reported energy intake to basal metabolic rate (EI:BMR) was used to identify energy misreporters (over- reporting and underreporting).21Each patient’s estimated basal metabolic rate was calculated using the Harris- Benedict equation.1Energy misreporters were checked at three timepoints, and misreported data were excluded from the analysis. Misreporters were defined as subjects outside the 95% confidence limit of agreement as measured by calculated EI:BMR ratios.22 In this study, we used EI:BMR ratios of,0.8, 0.8 – 2.4, and.2.4 as underre- porters, acceptable reporters, and overreporters of energy intake, respectively.23
Functional Status Assessment
Handgrip strength (HGS) test as a marker of functional status was carried out with the nonfistula hand using Jamar hand dynamometer (BK-7498; Fred Sammons, Inc., Burr Ridge, IL). HGS was indicative of muscle function as it measures the maximal voluntary force of the arm.24Three readings were recorded, and the median value was used.
Ramadan Fasting Practice
Adherence to fasting was assessed using a self- administered fasting tracking record. On the first visit before Ramadan (V0), subjects were instructed to record the number of fasting days and missed fasting days during Ramadan. They were also asked to record the cause of non- adherence pertaining to missed fasting days. On the visit during Ramadan (V1), subjects were interviewed on the to- tal number of fasting days to date. During the final visit after Ramadan (V2), subjects were asked about fasting commit- ment during the remaining number of fasting days. These data were cross-checked with the tracking record, and the causes of nonadherence to fasting were noted. Subjects were categorized into two groups based on the number of fasting days (,20 days and$20 days). This cutoff point was selected as metabolic and physiological changes per- taining to fasting are reported to occur after 20 days of fast- ing.25,26 This approach has also been used in previous studies27,28 to truly reflect the effect of Ramadan fasting on physical changes and nutritional status of the patients.
Statistical Analysis
Statistical analysis was performed to differentiating pa- tients who fasted for,20 days and$20 days. Variables in this HD population were presented as frequency (percent- ages) or mean6standard deviation or median (interquar- tile range) data, as appropriate. Repeated-measures analysis of variance was used to analyze the mean differences of measured variables between three timepoints (V0: before Ramadan; V1: during Ramadan; and V2: after Ramadan).
A potential cofounder such as hydration status was adjusted for biochemical analysis. Statistical significance was set at P,.05 for all parameters.
Results
Sociodemographic Factors and Ramadan Fasting
Of the total 226 screened Muslim patients on HD who reported they would voluntarily fast during Ramadan, 166 were deemed eligible, but only 102 patients consented to participate in the study (Fig. 1). During the course of the study, 15 patients dropped out for reasons of hospitalization (n 5 7), death (n 5 3), transfer to another HD center (n53), inability to fast (n51), and early withdrawal of consent (n 51). Of the final 87 patients who completed the study, 55.2% were male and mean 6 SD age was 54.362.2 years, with dialysis vintage of 856147 months.
Patient characteristics including comorbidities and cause of
renal failure are presented inTable 1. There was an equal distribution of subjects that fully adhered to Ramadan fast- ing (29 days of fasting, equivalent to 1 Islamic calendar month) and those who did not. Sixty-eight of 87 patients (78%) reported fasting for$20 days with the median and interquartile range being 28 (8) days, respectively. Majority of subjects missed fasting during dialysis days. None of these
patients were hospitalized or reported any adverse events during Ramadan, and their fasting practices are presented inTable 2.
Anthropometry, Body Composition, Blood Pressure, and Functional Status Assessment
Comparative mean changes in nutritional status parame- ters between timepoints are provided inTable 3andTable 4 Table 1.Sociodemographic Background of Subjects
(n587)
Sociodemographic
background Mean6SD Frequency (%)
Gender
Male 48 (55.2)
Female 39 (44.8)
Age (years) 54.3612.2
Level of education
None 3 (3.5)
Primary 7 (8.0)
Secondary 48 (55.2)
Tertiary 29 (33.3)
Cause of renal failure
Hypertension 35 (40.2)
Diabetes mellitus 33 (37.9)
Unknown 8 (9.2)
Glomerulonephritis 2 (2.3)
Others 9 (10.4)
Underlying comorbidities
Hypertension 69 (79.3)
Diabetes mellitus 35 (40.2)
Hyperlipidemia 18 (20.7)
Anemia 9 (10.3)
Dialysis vintage (months) 856147 SD, standard deviation.
Table 2.Ramadan Fasting Practices (n587) Ramadan fasting practices
Median (IQR)
Frequency (%) Full fasting
Yes 42 (48.3)
No 45 (51.7)
Number of fasting days 28 (8)
,20 days 19 (21.8)
$20 days 68 (78.2)
Frequency of missed fasting days
Nondialysis day 17 (37.8)
Dialysis day 28 (62.2)
Causes for nonadherence to fasting
Feeling fatigue 20 (44.4)
Feeling ill 11 (24.4)
Self-reported symptoms of hypoglycemia
7 (15.7)
Menstruation 5 (11.1)
Others 2 (4.4)
IQR, interquartile range.
Full fasting is defined as 29 days of fasting equivalent to 1 Islamic calendar month.46
Screening at 3 HD centres (n=226)
Eligible patients (n=166)
Consented patients (n=102)
Completed study (n=87)
Excluded (n=60)
• Unable to fast (n=20)
• Non-ambulatory (n=22)
• Blind/disable (n=15)
• Poor compliant to treatment (n=3)
Refused to consent (n=64)
Dropout (n=15)
• Hospitalized during study period (n=7)
• Passed away (n=3)
• Transferred out (n=3)
• Unable to fast (n=1)
• Refused to continue participation (n=1)
Figure 1.Flowchart of subjects’ recruitment. HD, hemodialysis.
for subjects who fasted for $20 days and ,20 days, respectively.
For patients who fasted for$20 days (Table 3), signifi- cant decreases were observed in IDWG (2.6 6 0.9 vs 2.3 6 0.9 kg, P 5 .007) and WC (92.1 6 11.4 vs 90.3610.7 cm,P5.005) among male subjects. On the other hand, female subjects dominantly showed a signifi- cant decrease in BMI (26.8 6 4.8 vs 26.5 6 4.6 kg, P5.055), IDWG (2.561.0vs2.160.6 kg,P5.030), and WC (91.76 11.6vs90.26 11.3 cm,P5.019). In addition, significant decreases in MAC (30.2 6 3.9 vs 29.7 6 3.9 cm, P 5 .015), body fat percentage (29.0 6 8.5 vs 28.8 6 8.4%, P 5.007), and fat tissue mass (FTM) (23.2 6 8.4 vs 22.2 6 8.8 kg, P 5.045) were observed during Ramadan in all patients although it was not significantly different within gender groups. How- ever, all these changes became normalized to the baseline values (allP..05) 4 weeks after Ramadan. Other anthro- pometrics parameters (TSF, MAMC, MAMA, FTI, LTM, and lean tissue index) remained unchanged during Ramadan for both genders (allP..05). HGS as a marker of functional status remained unchanged during Ramadan but improved significantly after Ramadan for both genders (male5V0: 24.6 68.0vsV2: 26.868.5 kg,P5.007;
female5V0:16.665.3 vs V2:18.966.4 kg, p,.001).
Blood pressure for this patient group was not significantly altered (allP..05) between V0, V1, and V2measurements.
For subjects who fasted for,20 days (Table 4), only WC was significantly reduced during Ramadan (97.06 13.8 vs94.2613.1 cm,P5.019), while other anthropometric and body composition parameters remained unaffected.
Blood Biochemistry
In patients who fasted for $20 days, blood chemistry analysis (Table 5) indicated significant decreases in serum phosphate (V0: 6.12 6 1.55vs V1: 5.626 1.90 mg/dL, P 5.004) and serum albumin (V0: 4.37 6 0.27 vs V1: 4.1160.23 g/dL,P,.001) during Ramadan compared with pre-Ramadan values.nPCR as a surrogate marker of dietary protein intake was also significantly decreased dur- ing Ramadan (V0:1.0460.20vsV1:0.9360.20 g/kg/day, P,.001). In parallel with decreasednPCR, there were sig- nificant decreases in serum urea (V0: 124.49629.90 vs V1: 110.97 6 29.26 mg/dL, P ,.001) and creatinine (V0: 12.6762.99 vs V1: 11.8663.36 mg/dL,P5.003) during Ramadan fasting. However, lipid profiles and high- sensitivity C-reactive protein as a marker of inflammation were not significantly altered (allP..05). However, for pa- tients who fasted for,20 days (Table 6), all blood biochem- istry parameters remained unchanged except for a significant decrease in serum albumin (V0: 4.2460.37vs V1: 4.7460.63 g/dL,P,.001).
Dietary Intake Assessment
For dietary intake assessment, a total of 26 (30%) energy misreporters (all were underreporters) were identified.
Each timepoint had different numbers of misreporters (V0: 18.4% [n516], V1: 16.1% [n514], and V2: 11.5%
[n510]), and these were excluded. Dietary data of 61 sub- jects were included in the final analysis. From the analysis, it was revealed that energy and macronutrient intakes during Ramadan for subjects who fasted$20 days (n554) were not significantly altered compared to pre-Ramadan intakes for both male and female subjects (bothP..05). Interest- ingly, dietary potassium intake significantly increased (V0: 8906322vsV1: 10056296 mg,P5.008) comparatively and predominantly in female subjects. Contrarily, phos- phate intake significantly decreased (V0: 1119 6 940 vs V1: 5496204 mg, P,.001) during Ramadan, and the trend was observed in both genders. Notably, sodium and fluid intakes during Ramadan were not significantly different from pre-Ramadan values (bothP..05). Nutri- tional information on reported dietary intakes is presented in Table 7. There were no significant changes in dietary intake for subjects fasting,20 days (n5 7) as shown in Table 8.
Discussion
Spirituality and religious practices such as fasting can lead to changes in body’s important physiological reaction.3 Religious practices have been shown to moderate health outcomes, especially in terms of mortality reduction, treat- ment compliance, disease coping, and also in recovery.29 For Muslims, it is believed that spiritual rewards for good deeds are multiplied during Ramadan.30This may explain why many people despite poor health still choose to fast during Ramadan.31In a non-CKD population study inves- tigating Epidemiology of Diabetes and Ramadan (EPI- DIAR), 42.8% and 78.7% of patients with type 1 and type 2 diabetes were able to fast for more than 15 days with the average number of fasting days being 23 and 27 days, respectively.32 Similarly, in this study, we found that majority of the patients (78.2%) were able to fast for more than 20 days with 48% fully fasting for the whole Is- lamic month. Our study also indicated that 13.8% of the subjects fasted only on nondialysis days, while others were able to fast on both dialysis and nondialysis days. These findings indicate that Ramadan fasting was a well- accepted practice in the study population. This is also sup- ported by another Malaysian study which reported 89% of patients on HD (n 5 35) fasted for more than 15 days.7 With regard to the causes of nonadherence, subjects were likely to skip fasting if feeling fatigue (44.4%), feeling ill (24.4%), and presence of self-reported symptoms of hypo- glycemia such as shakiness, dizziness, and cold sweat (15.7%) with higher frequency of nonadherence occurred during dialysis days. Common recurring symptoms re- ported during Ramadan fasting are hypoglycemic symp- toms, lethargy, and sleepiness.33
Our study showed that Ramadan fasting lead to temporal changes in nutritional status parameters among patients on
Table 3.The Effects of Ramadan Fasting on Anthropometry, Body Composition, Blood Pressure, and Functional Status for Patients Fasting$20 Days
Parameter
Gender: all (n568);
male (n543);
female
(n525) V0 V1 V2
Mean difference6
SD (V0-V1)
Mean difference6
SD (V1-V2)
Mean difference6
SD (V0-V2)
aP trend Anthropometric assessment
BMI (kg/m2)
All 26.064.2b 25.864.1b,c 25.964.2c 0.2060.49 20.1560.49 0.0560.60 .007*
Male 25.563.8 25.463.7 25.463.8 0.1760.52 20.1360.44 0.0460.60 .107 Female 26.864.8b 26.564.6b 26.764.7 0.2660.43 20.1860.59 0.0860.61 .055*
Average IDWG (kg)
All 2.660.9b 2.260.8b,c 2.561.0c 0.3460.85 20.2760.68 0.0660.79 .001*
Male 2.660.9b 2.360.9b,c 2.761.1c 0.3260.94 20.3760.72 20.0560.79 .007*
Female 2.561.0b 2.160.6b 2.260.7 0.3660.69 20.1060.55 0.2660.80 .030*
WC (cm) All 92.0611.4b 90.3610.7b,c 91.5611.6c 1.7063.10 21.2363.12 0.4763.48 ,.001*
Male 92.1611.4b 90.3610.6b 91.4611.4 1.8063.40 21.1563.21 0.6563.84 .005*
Female 91.7611.6b 90.2611.3b 91.6612.0 1.5262.53 1.3663.01 0.1662.78 .019*
MAC (cm)
All 30.263.9b 29.763.9b 30.064.2 0.5061.44 20.3061.45 0.2061.33 .015*
Male 30.063.6 29.663.7 29.864.0 0.4061.38 20.2261.52 0.1961.20 .162 Female 30.564.4 29.864.2 30.364.6 0.6661.55 20.4561.36 0.2261.56 .088 TSF
(mm)
All 16.666.3 16.466.3 16.667.2 0.2463.29 0.2263.99 0.0265.10 .828 Male 14.766.2 14.366.0 14.566.2 0.5462.64 20.1663.89 0.3864.41 .573 Female 19.765.4 20.065.2 20.367.6 20.2964.12 20.3264.15 20.6166.03 .771 MAMC
(cm)
All 24.862.8 24.563.1 24.863.3 0.4261.51 20.2362.12 0.1962.03 .194 Male 25.362.5 25.162.9 25.363.2 0.2361.42 20.1762.36 0.0762.01 .674 Female 24.363.3 23.563.1 23.863.5 0.7561.63 20.3561.69 0.4061.63 .126 MAMA
(cm2)
All 41.4610.9 39.9611.8 40.9613.1 1.5466.09 21.0569.11 0.4968.64 .275 Male 41.6610.0 40.9612.0 41.6612.9 0.7365.80 20.77610.18 20.0468.78 .734 Female 41.1612.5 38.2611.3 39.7613.7 2.9266.44 21.5367.10 1.3968.50 .153 Body
fat (%)
All 29.068.5b 28.868.4b 29.068.4 0.2860.68 0.2060.69 0.0860.84 .007*
Male 24.665.6 24.465.7 24.565.5 0.2460.72 20.1760.62 0.0760.84 .102 Female 36.767.1b 36.367.0b 36.667.1 0.3660.60 20.2460.82 0.1160.85 .069 FTM (kg) All 23.268.4b 22.268.8b 23.168.3 0.9763.50 20.8763.54 0.1063.28 .045*
Male 21.267.9 20.568.0 21.568.5 0.6763.27 0.9663.41 20.2963.68 .182 Female 26.468.3 24.969.4 25.667.6 1.4663.96 20.7263.94 0.7462.63 .134 FTI All 12.564.8 12.065.1 12.664.9 0.4961.88 20.6062.63 20.1062.58 .105 Male 10.964.3 10.664.4 11.364.9 0.3261.62 20.7362.87 20.4163.03 .209 Female 15.064.6 14.365.3 14.764.2 0.7862.27 20.4062.24 0.3861.55 .177 LTM (kg) All 35.9610.4 36.3611.0 35.3610.1 20.3864.89 0.9764.89 0.6064.50 .250 Male 40.2610.2 40.2610.9 39.2610.0 0.0464.09 1.0264.14 1.0664.90 .224 Female 28.965.9 30.067.9 29.066.5 21.0666.01 0.9066.03 20.1663.72 .529 LTI All 13.963.2 14.063.4 13.763.2 20.1561.97 0.3661.95 0.2161.71 .309 Male 15.063.2 15.063.4 14.663.2 0.0361.50 0.3361.54 0.3661.79 .296 Female 12.162.2 12.563.0 12.162.4 20.4362.56 0.4062.52 20.0461.59 .575 Functional status assessment
HGS (kg) All 21.668.1b,c 22.868.0b 23.668.5c 21.1863.50 20.8163.15 22.0063.50 ,.001*
Male 24.668.0b 25.967.5 26.468.5b 21.3263.89 20.4363.28 21.7563.62 .007*
Female 16.665.3b 17.565.8c 18.966.4b,c 20.9362.63 21.4662.8 22.3862.8 ,.001*
Clinical assessment Systolic BP
(mmHg)
All 156623 155621 156624 1618 22618 21619 .906
Diastolic BP (mmHg)
83613 83612 83613 0611 1612 1612 .823
BP, blood pressure; BMI, body mass index; FTI, fat tissue index; FTM, fat tissue mass; IDWG, intradialytic weight gain; LTI, lean tissue index;
LTM, lean tissue mass; MAC, mid-arm circumference; MAMA, mid-arm muscle area; MAMC, mid-arm muscle circumference; TSF, triceps skin- fold; V0, 2 weeks before Ramadan; V1, 4th week of Ramadan; V2, 4 weeks after Ramadan; WC, waist circumference.
aRepeated-measures analysis of variance; in whichPis set at,.05 for significance.
b,cSame superscript indicative of significance in the same evaluation.
*P,.05.
maintenance HD. We observed that body weight partic- ularly BMI and body fat mass as measured by WC, MAC, body fat percentage, and FTM were significantly reduced with no significant changes in LTM during Ramadan fasting. Interestingly, we found that daily die- tary energy and macronutrient intakes remained un- changed compared with the nonfasting period, despite reduction in meal frequency during Ramadan which may be explained by the tendency to overcompensate food intake during the breaking of fast.34 In contrast, a study among Emiratis of Ajman (UAE) reported that to- tal energy intake remained the same comparatively before Ramadan partly due to compensation with larger meals despite a decrease in the frequency of meals consumed, thus nullifying the common belief that Mus- lims tend to overcompensate food intake during fasting month.35 Although daily dietary intake remained un- changed during Ramadan, the decrease in body weight and fat mass observed could be explained by the loss of water and degradation of fat tissues as a primary source of energy during fasting following the depletion of glycogen stores, while preserving muscle mass.36
The preservation of muscle mass is important in HD population as it is associated with lower all-cause mortal- ity37and improved muscle function.38In our study, we uti- lized HGS as a simple, noninvasive, and quick method to
assess muscle function.39Our study showed that although there was no change in LTM during Ramadan, interest- ingly, HGS was significantly increased, indicating improve- ment in the muscle function. We observed that HGS which strongly correlates with LTM38 was not affected by the decrease in BMI during Ramadan, and this is expected as BMI does not distinguish body composition.40 Plausible explanation on the improvement of HGS could be due to increase in physical activity pertaining to performing extended hours of praying after sunset (equivalent to stretching-related movement),41 as reported in another study.35,42However, muscle function is dependent on not only muscle mass per se but also other factors such as the uremic condition known as uremic myopathy which could play a role.43
Reduction in body fat mass reflected by reduction in FTM and WC in our patients observing Ramadan fasting has been similarly reported in healthy as well as diabetic populations.44,45 We utilized WC for assessment of visceral fat as it is commonly used in patients on HD.46 Visceral fat is a crucial factor when predicting mortality and cardiovascular complications.46Many studies have re- ported that high visceral fat is associated with higher risk of inflammation and atherosclerosis which further exacer- bate the risk of cardiovascular complications in HD popu- lation.47-49 However, this observation could also be Table 4.The Effects of Ramadan Fasting on Anthropometry, Body Composition, Blood Pressure and Functional Status for Patients Fasting,20 Days (n519)
Parameter V0 V1 V2
Mean difference6SD
(V0-V1)
Mean difference6SD
(V1-V2)
Mean difference6SD
(V0-V2) aPtrend Anthropometric assessment
BMI (kg/m2) 26.965.0 26.464.9 27.065.2 20.4360.48 20.5261.09 20.0961.22 .088 Average
IDWG (kg)
2.260.7 2.160.9 2.160.8 0.1060.68 0.0460.75 0.1460.65 .658 WC (cm) 97.0613.8b 94.2613.1b 95.7612.4 2.8562.81 21.5264.26 1.3364.45 .019*
MAC (cm) 30.363.7 30.364.2 32.1610.3 20.0461.31 1.8269.86 21.86610.2 .453 TSF (mm) 19.966.2 19.267.0 20.567.4 0.7262.81 1.3162.71 20.5962.96 .159 MAMC (cm) 24.163.0 24.363.1 23.462.7 20.2761.49 0.9561.92 0.6861.50 .062 MAMA (cm2) 39.3610.3 40.4611.4 36.669.2 21.1065.88 3.7867.59 2.6965.92 .053 Body fat (%) 34.467.8 33.867.9 34.568.5 0.5860.66 20.6961.49 20.1161.65 .106 FTM (kg) 25.268.97 24.667.4 25.668.0 0.5864.93 21.0664.17 0.4862.88 .510 FTI 14.065.3 13.564.5 14.264.7 0.4762.82 20.6462.33 20.1761.80 .477 LTM (kg) 31.969.3 32.667.1 31.468.0 20.6967.33 1.2665.99 0.5764.90 .675 LTI 12.863.3 13.262.7 12.662.9 20.3263.04 0.5662.43 0.2463.04 .625 Functional assessment
HGS (kg) 19.766.8 19.466.2 20.066.9 0.1763.98 20.5864.21 20.4164.22 .820 Clinical assessment
Systolic BP (mmHg)
163620 161624 161618 2616 1612 2616 .785
Diastolic BP (mmHg)
84615 85613 8469 21613 169 0613 .866
BP, blood pressure; BMI, body mass index; FTI, fat tissue index; FTM, fat tissue mass; IDWG, intradialytic weight gain; LTI, lean tissue index;
LTM, lean tissue mass; MAC, mid-arm circumference; MAMA, mid-arm muscle area; MAMC, mid-arm muscle circumference; TSF, triceps skin- fold; V0, 2 weeks before Ramadan; V1, 4th week of Ramadan; V2, 4 weeks after Ramadan; WC, waist circumference.
aRepeated-measures analysis of variance in whichPis set at,.05 for significance.
bSame superscript indicative of significance in the same evaluation.
*P,.05.
indicative of loss of extracellular fluid rather than visceral fat.50 Nonetheless, Ramadan fasting could provide a short-term benefit in terms of lowering body fat mass while preserving muscle mass in this population.
We measured IDWG as an indicator of fluid control. It has been previously reported that IDWG correlates with blood pressure control and survival in patients on HD.51 Our study found that Ramadan fasting leads to significant Table 5.The Effects of Ramadan Fasting on Blood Biochemistry Profiles for Patients Fasting$20 days (n568)
Parameter V0 V1 V2
Mean difference6SD
(V0-V1)
Mean difference6SD
(V1-V2)
Mean difference6SD
(V0-V2) aPtrend Predialysis
urea (mg/dL)
124.49629.90b 110.97629.26b,c 119.81629.10c 13.52624.10 28.84624.77 4.68625.83 ,.001*
Creatinine (mg/dL)
12.6762.99b,c 11.8663.36b 11.8163.10c 0.8162.18 0.0562.28 0.8662.33 .003*
Sodium (mEq/L)
138.5762.61b 137.2163.15b,c 138.5463.69c 1.3662.74 21.3363.72 0.0363.52 .002*
Potassium (mEq/L)
4.7260.60b 4.7760.63 5.0060.75b 20.0460.47 20.2260.75 20.2660.63 .004*
Phosphate (mg/dL)
6.1261.55b 5.6261.90b,c 6.0761.60c 0.5161.48 20.4561.24 0.0661.32 .004*
Albumin (g/dL)
4.3760.27b,c 4.1160.23b,d 4.2760.25c,d 0.2660.25 20.1660.25 0.0960.25 ,.001*
TC (mg/dL) 173.73641.95b 169.77639.33 163.80634.79b 3.97625.56 5.97622.02 9.93622.35 .003*
HDL-C (mg/dL)
38.78610.29 37.96611.08b 40.44610.26b 0.8266.35 22.4866.43 21.6665.69 .004*
LDL-C (mg/dL)
93.83640.33 97.86638.12 91.96632.87 24.03629.11 5.90628.78 1.87627.29 .220 hsCRP
(mg/L)
0.9361.37 1.1661.53 1.0861.55 20.2361.32 0.0961.90 20.1461.98 .522 nPCR
(g/kg/day)
1.0460.20b 0.9360.20b,c 1.0060.19c 0.1160.25 20.0660.16 0.0560.16 ,.001*
hsCRP, high-sensitivity C-reactive protein; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol;
nPCR, normalized protein catabolic rate; TC, total cholesterol; V0, 2 weeks before Ramadan; V1, 4th week of Ramadan; V2, 4 weeks after Ramadan.
aRepeated-measures analysis of variance adjusted for hydration;Pis set at,.05 for significance.
b,cSame superscript was indicative of significance in the same evaluation.
*P,.05.
Table 6.The Effects of Ramadan Fasting on Blood Biochemistry Profiles for Patients Fasting,20 Days (n519)
Parameter V0 V1 V2
Mean difference6SD
(V0-V1)
Mean difference6SD
(V1-V2)
Mean difference6SD
(V0-V2) aPtrend Predialysis
urea (mg/dL)
105.60637.56 95.41631.94 106.89635.86 10.18634.13 211.48630.03 21.30628.77 .225 Creatinine (mg/dL) 10.7461.80 10.5862.06 10.5061.79 0.1661.13 0.0861.05 0.2360.87 .603 Sodium (mEq/L) 137.5862.80 136.4262.34 138.1663.37 1.1662.66 21.7463.57 20.5863.88 .091 Potassium (mEq/L) 4.5360.55b 4.7460.63 4.8460.55b 20.2260.44 0.1060.44 20.3160.44 .013*
Phosphate (mg/dL) 6.1861.86 6.0562.17 6.1161.71 0.1461.13 20.0661.00 0.0861.26 .872 Albumin (g/dL) 4.2460.37b 4.0460.37b,c 4.2860.47c 0.2060.17 20.2360.31 20.0460.22 ,.001*
TC (mg/dL) 182.68638.67 181.54645.61 176.93642.40 1.14620.18 4.61617.30 5.75616.08 .346 HDL-C (mg/dL) 40.9269.97b 40.77612.16 43.44611.22b 0.1465.32 22.6664.53 22.5264.14 .030*
LDL-C (mg/dL) 99.14628.5 102.80636.58 95.69636.79 23.66621.23 7.11614.69 3.45615.65 .220 hsCRP (mg/L) 1.0261.32 0.7860.63 0.7460.70 0.2561.44 0.0460.48 0.2861.35 .456 nPCR (g/kg/day) 0.9060.27 0.8560.21 0.9160.23 0.0660.26 20.0660.22 20.0160.22 .471 hsCRP, high-sensitivity C-reactive protein; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol;
nPCR, normalized protein catabolic rate; TC, total cholesterol; V0, 2 weeks before Ramadan; V1, 4th week of Ramadan; V2, 4 weeks after Ramadan.
aRepeated-measures analysis of variance adjusted for hydration;Pis set at,.05 for significance.
b,cSame superscript was indicative of significance in the same evaluation.
*P,.05.
