Saudi Journal of Kidney Diseases and Transplantation

: 2020  |  Volume : 31  |  Issue : 3  |  Page : 582--588

Effect of Ramadan fasting on arterial stiffness parameters among Egyptian hypertensive patients with and without chronic kidney disease

Ahmed A Eldeeb, Mostafa A Mahmoud, Ahmed B Ibrahim, Elshahat A Yousef, Alaa A Sabry 
 Department of Internal Medicine, Nephrology and Dialysis Unit, Mansoura University Hospital, Mansoura University, Mansoura, Egypt

Correspondence Address:
Ahmed A Eldeeb
Department of Internal Medicine, Nephrology and Dialysis Unit, Mansoura University Hospital, Mansoura University, Mansoura


Arterial stiffness (AS) increases progressively in patients with chronic kidney disease (CKD). It is a strong predictor of cardiovascular and all-cause mortality. This study aims at evaluate of the effect of Ramadan fasting on AS parameters, augmentation index (AIx), and pulse wave velocity (PWV) in hypertensive patients with and without CKD. A cohort of 71 patients (mean age = 57.14 ± 14.5 years, 42 females and 29 males) were enrolled in this study; 34 with CKD and 37 without CKD. All patients had hypertension, while 25 patients also had diabetes mellitus. Serum creatinine (Cr), serum urea, estimated glomerular filtration rate (eGFR) by CKD-EPI formula, brachial and central systolic blood pressure (BSP and CSP respectively), brachial and central diastolic blood pressure (BDP, CDP, respectively), AIx and PWV (measured by cuff based oscillometric method) were assessed before and after Ramadan fasting. In patients without CKD BSP, BDP, CSP, and CDP significantly decreased (P = 0.0001, 0.0001, 0.0001, and 0.0001, respectively). In patients with CKD BSP and CSP significantly decreased (P = 0.005 and 0.005), while BDP and CDP decreased, but the change was not statistically significant. AIx significantly decreased in patients without CKD (P = 0.0001, mean 36.24 before and 26.22 after Ramadan fasting), but did not significantly change in patients with CKD (P 0.381 mean 25.94 before and 25 after Ramadan fasting). PWV decreased in both groups, but the change was not significant. Serum Cr significantly increased (P = 0.03 mean 1.06 mg/dL before and 1.11 mg/dL after Ramadan fasting), while eGFR did not significantly decrease (P = 0.072, mean 69.73 mL/ min/1.73 m2 before and 67.3 mL/min/1.73 m2 after Ramadan fasting) in patients without CKD. Serum Cr significantly decreased (P 0.028 mean 1.93 mg/dL before and 1.87 mg/dL after Ramadan fasting) and eGFR significantly increased (P 0.006 mean 32.65 mL/min/1.73 m2 before and 34.68 mL/min/1.73 m2 after RF) in patients with CKD. Ramadan fasting is associated with improved peripheral and central blood pressure control in hypertensive patients with and without CKD. It is also associated with improved arterial compliance (decreased AIx) in hypertensive patients without CKD.

How to cite this article:
Eldeeb AA, Mahmoud MA, Ibrahim AB, Yousef EA, Sabry AA. Effect of Ramadan fasting on arterial stiffness parameters among Egyptian hypertensive patients with and without chronic kidney disease.Saudi J Kidney Dis Transpl 2020;31:582-588

How to cite this URL:
Eldeeb AA, Mahmoud MA, Ibrahim AB, Yousef EA, Sabry AA. Effect of Ramadan fasting on arterial stiffness parameters among Egyptian hypertensive patients with and without chronic kidney disease. Saudi J Kidney Dis Transpl [serial online] 2020 [cited 2021 Jun 16 ];31:582-588
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Cardiovascular diseases are the most common cause of death in the world.[1] Cardiac abnormalities start to develop early in chronic kidney disease (CKD) patients. Cardiovascular causes of mortality in patients with stage 2 CKD are twice higher and in patients with stage 3 CKD are threefold higher when compared to subjects with normal renal function. The risk of cardiovascular diseases, including congestive heart failure, atrial fibrillation, coronary artery disease, peripheral artery disease, and stroke is increased two-fold in patients with estimated glomerular filtration rate (eGFR) <70 mL/min/1.73 m2.[2]

Arterial stiffness (AS) is an efficient predictor of cardiovascular events.[3] It could predict major adverse cardiac events in CKD patients with the apparently normal cardiovascular examination and normal ejection fraction.[4] AS results from functional and structural abnormalities of the vessel wall and reflects the end-organ damage.[5] The AS is assessed mainly by aortic pulse wave analysis (PWA) to get the pulse wave velocity (PWV) and augmentation index (AIx). The PWV is assessed by calculating the travel time of the pulse wave between two reference points. The higher the PWV values, the more the AS and the more the cardiovascular risk. On the other hand, the AIx reflects compliance of the arteries and is defined as a percentage of the height of a reflected wave relative to the incident wave. Its percentage is inversely correlated to arterial compliance.

Noninvasive assessment of central (aortic) systolic and diastolic blood pressure (CSP and CDP, respectively) and PWA is done by either applanation tonometry over the radial or carotid arteries, ultrasound or by oscillometric methods using a standard brachial blood pressure cuff to evaluate the brachial artery waveform at or near diastolic pressure.[7]

Ramadan is the most important lunar month for the Islamic faith. Muslims avoid eating, drinking, and smoking from dawn to sunset for a period of one lunar month. The duration of Ramadan fasting on a certain day varies from region to region and in the same region from one year to another.[3] Fasting during Ramadan represents a radical change in lifestyle and food and drinking habits. This change may affect cardiovascular risk in patients with coronary artery disease and cerebrovascular disease.[8]

Only a few studies have evaluated changes in cardiovascular risk factors, including body weight,[9],[10] glycemic control, dyslipidemia, and blood pressure control[11] with Ramadan fasting. These studies revealed contradictory results.

A Turkish study revealed improvement of AS in healthy controls after fasting Ramadan, but the changes were not statistically significant.[3] To the best of our knowledge, no studies have evaluated the changes in AS after fasting Ramadan in patients with CKD.

This study aimed at evaluation of the effect of Ramadan fasting on AS and central blood pressure in hypertensive patients with and without CKD.

 Patients and Methods

This was a prospective self-controlled study that included 71 hypertensive patients (41 with and 29 without CKD) who fasted the whole lunar month of Ramadan. Patients were selected from attendants of the nephrology outpatient clinic of Mansoura University Hospital. Patients with uncontrolled diabetes mellitus (DM), nephrolithiasis, and significant heart disease (history of myocardial infarction or heart failure NYHA III or IV) were excluded from the study. Patients with CKD stage IV and V were counseled against fasting, but patients who insisted to fast were not excluded from the study. Written informed consent was signed by all participants. The study protocol was approved by the institutional research board (IRB) of the Faculty of Medicine, Mansoura University, with the code number: R/17.04.56.

The study was performed in the holy month of Ramadan, the year 1438 of the Hijri calendar. This was in the summer. Patients have fulfilled fasting for 29 days from the 27th of May to 25th of June 2017. Fasting duration ranged from 15 h and 35 min to 15 h and 55 min. Patients were evaluated the week before and the week after Ramadan fasting regarding:

Routine general examinationBodyweight, height, and body mass index (BMI) calculationAS was assessed by Mobi-O-Graph (Manufacturer: I.E.M. Industrielle Entwicklung Medizintechnik GmbH, Germany). This device uses brachial oscillometric method for PWA. Arterial pulsation generates the pressure oscillations, which are transmitted to blood pressure cuff and measured by transducer to be fed into microprocessor. Computerized software records pulse waves from the brachial artery and by a transfer factor derive central aortic pulse wave. It further undergoes point-based and area-based analysis by computer to derive various cardiovascular parameters. A blood pressure cuff of appropriate size was chosen based on mid-arm circumference (small, medium, or large) and applied to the left arm using the standard protocol. All readings were taken after 10 min of rest, in subjects who avoided eating for 2 h and smoking for 12 h before the test. The test was performed in a calm room, avoiding external influences or arm movement. The device displayed brachial systolic pressure (BSP), brachial diastolic pressure (BDP), CSP, CDP, AIx, and PWV.Venous blood samples were taken for assay of serum creatinine and urea. Samples were centrifuged for 10 min at a rate of 5000 rpm/min, and serum was frozen at -20°C. eGFR was calculated according to the CKD-EPI equation.[12]

 Statistical Analysis

The collected data were analyzed using the Statistical Package for the Social Sciences (SPSS) software version 17 (SPSS Inc., Chicago, Illinois, USA). Patients were divided into two groups (CKD and non-CKD). Qualitative variables were expressed as number and percentage, while quantitative variables were expressed as mean ± standard deviation. Skewness and kurtosis were evaluated to assess the normality of variables. Demographic data were compared between the two groups using Mann–Whitney test. All variable were compared before and after RF using paired-samples t-test for parametric variables and Wilcoxon test for nonparametric variables.


This study included 71 hypertensive patients who were divided into two groups; 34 patients (20 females and 14 males) with CKD and 37 patients (22 females and 15 males) without CKD. The mean age was 59 years for patients with CKD and 55 years for patients without CKD. It included 25 patients with DM (14 with CKD and 11 without CKD).

There was no significant difference between both groups regarding age, sex, and DM, as shown in [Table 1].{Table 1}

Both CSP and BSP decreased significantly after RF in both groups. Both CDP and BDP decreased significantly after RF in patients without CKD, but the drop was not statistically significant in patients with CKD, as shown in [Table 2] and [Table 3].{Table 2}{Table 3}

Regarding the parameters of AS, PWV did not show significant change in both groups while AIx significantly decreased in patients without CKD, as showed in [Table 2] and [Table 3].

Both body weight and BMI decreased significantly after RF in CKD and non-CKD groups as shown in [Table 4].{Table 4}

Regarding renal function, eGFR did not significantly change in patients without CKD while it significantly increased in patients with CKD, as shown in [Table 5].{Table 5}

Patients without DM had a significant decrease of CSP, BSP, CDP, BDP, and AIx after RF, while patients with DM had a significant decrease of BSP only as shown in [Table 6] and [Table 7].{Table 6}{Table 7}


Our study demonstrated a significant drop of systolic blood pressure with RF either measured peripherally on the brachial artery or central aortic pressure measured by oscillometric method in hypertensive patients with and without CKD. Diastolic blood pressure significantly dropped only in patients without CKD. The nonsignificant change in diastolic blood pressure in CKD group may be explained by decreased arterial compliance resulting from more atherosclerosis and arterial calcification expected in this group. This explanation copes with the nonsignificant change of AIx (which reflects arterial wall compliance) in patients with CKD while it significantly improved in patients without CKD.

Previous studies on blood pressure changes with RF have demonstrated improved blood pressure control in hypertensive patients. Though decreased in most studies, the drop of blood pressure with RF was statistically significant in some studies in non-CKD hypertensive patients[13],[14] and in CKD patients[15] while the drop of blood pressure wasn’t statistically significant in others.[16],[17] The improved blood pressure control is mainly related to weight loss which was statistically significant in our study and in the previous studies that revealed a significant decrease of blood pressure.[13],[14],[15] To our knowledge, this was the first study to evaluate the effect of RF on AS in hypertensive patients. We demonstrated slight improvement in AIx but not PWV in hypertensive patients without CKD, while both AS parameters did not significantly change in patients with CKD. A previous study revealed no significant change in AS parameters in healthy controls.[3] Ramadan fasting was associated with improved AIx, which reflects better arterial compliance in hypertensive patients without CKD. Ramadan fasting failed to achieve a similar effect in patients with CKD. More atherosclerosis and arterial calcification in patients With CKD may explain this result.

Our study demonstrated significant improvement of eGFR with RF in hypertensive patients with CKD while it did not significantly change in patients without CKD. Many studies have examined the effect of RF on renal function tests in CKD patients with variable results. Few studies revealed worsening renal functions with RF[15] while most studies demonstrated the safety of RF in these patients. A meta-analysis including six studies, of which three were done while RF was in hot seasons. This meta-analysis has confirmed this conclusion.[18] Another study compared a group of CKD patients who fasted Ramadan to a control group of CKD patients who did not fast and revealed similar results.[19]

In this study, patients without DM had significant improvement of blood pressure control and decreased AIx with RF, while patients with DM had only significant improvement of systolic blood pressure with RF. This may be explained by the worse metabolic profile of these patients associated with more atherosclerosis and less arterial compliance.

 Limitation of the Study

Further evaluation of the effect of RF on AS on a larger number of patients is needed. Evaluation of this effect in different geographic areas with different weather conditions, ethnic groups, social, and nutritional habits will help clarify this correlation.


Hypertensive patients with and without CKD having no significant heart disease can safely fast during Ramadan. Hypertensive patients with and without CKD having controlled DM can safely fast during Ramadan. Ramadan fasting have favorable effect on BMI and blood pressure control in these patients. Ramadan fasting is associated with improved arterial compliance in hypertensive patients without CKD and DM.

Conflict of interest: None declared.


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