Abstract
Objective
The impact of Ramadan fasting on the prevalence of renal colic (RC) remains controversial. This current study aimed to assess the correlation between Ramadan fasting, prevalence of RC and the rate of urgent endoscopic interventions due to urolithiasis.
Methods
This retrospective case–control study enrolled adult patients with a primary diagnosis of RC secondary to urolithiasis admitted to the emergency department during the years 2009–2019. The prevalence of RC and the rate of urgent urological interventions during Ramadan were compared with the pre- and post-Ramadan months in fasting Muslims and non-fasting non-Muslim patients.
Results
A total of 2781 patients with RC were included: 1014 (36.5%) were fasting Muslim and 1767 (63.5%) were non-fasting non-Muslim patients. No significant increase in RC admissions or urgent double J stent (DJS) insertions were observed between pre-Ramadan and Ramadan among fasting Muslims and non-fasting non-Muslim patients. However, fasting Muslims exhibited a significant increase of RC admissions post-Ramadan compared with Ramadan.
Conclusions
There was no correlation between increased RC admissions or urgent DJS insertions when fasting Muslims were compared with non-fasting non-Muslim patients during Ramadan. There were increased RC admissions during the post-Ramadan month, which might indicate a delayed effect of fasting on RC.
Introduction
Nephrolithiasis is a common kidney disorder associated with significant patient morbidity. 1 Renal colic (RC), the pain associated with nephrolithiasis, is one of the most frequent causes of emergency department (ED) referrals. In the Western world, the reported incidence of RC ED visits is 1 to 2 per 1000.2–4 Various clinical risk factors seem to contribute to renal colic occurrence. 5 Furthermore, low urine volume and dehydration are both risk factors for urinary stone formation. 6
Ramadan fasting is one of the fundamental religious observations of Islam. Fasting during Ramadan consists of strict abstinence of food, drinking and medication consumption from dawn to sunset. 7 The fast extends between 8–20 h depending upon the season and location during the 29–30 days of the Ramadan lunar calendar month. When Ramadan falls during the summer months, the risk for dehydration increases, especially in hot climates. 8 Such dehydration promotes secretion of antidiuretic hormone and adrenocorticotropic hormone, leading to a reduction in urine volume and an increase in calcium concentration, thereby affecting the rate of urinary tract stone formation. 9
The literature on the correlation between Ramadan fasting and the incidence of renal colic admissions due to urolithiasis remains inconclusive, with some reports finding such a correlation and other studies ruling out any such relationship.4,5,10,11 Clarifying the causal relationship may help physicians guide fasting patients who are prone to urolithiasis. Therefore, in order to increase the understanding of the potential causal relationship between Ramadan fasting and RC occurrence, this retrospective case–control study was undertaken. This current study aimed to answer several unanswered questions. First, while several studies examined the association between Ramadan fasting and emergent admission due to RC, few examined the need for urgent urological interventions due to RC, most notably ureteral stent insertion.4–6,8,10,12–14 In addition, existing reports on the subject were mainly performed in Muslim countries and thereby did not include a reference group.5,9–15 Finally, prior studies were carried out over short periods of time, so this current study aimed to capture RC events occurring in the weeks following Ramadan fasting, perhaps due to urolithiasis formed in the fasting period that manifested clinically at a later period.11,13–15
The primary objective of this current study was to examine the impact of Ramadan fasting on the incidence of RC admissions to an ED. The secondary objective was to evaluate the correlation between Ramadan fasting and the need for urgent urological and endoscopic interventions, such as double J stent (DJS) insertions secondary to urolithiasis. The study retrospectively compared a fasting population with a non-fasting neighbouring population during the same months over a 10-year period. It was assumed that fasting during Ramadan would be associated with an increased risk for RC ED admissions and urgent urological interventions.
Patients and methods
Study population
This retrospective case–control study reviewed all consecutive adult patients with a primary diagnosis of RC admitted to the Emergency Department at Hillel Yaffe Medical Centre, Hadera, Israel, a university-affiliated medical centre, between January 2009 and December 2019. This retrospective review used data from the electronic medical records. Hillel Yaffe Medical Centre is located in Northern Israel and serves a population of half a million residents comprised of Jews and Arabs (mainly Muslims). The inclusion criteria were as follows: (i) adult patients with a primary diagnosis of RC due to renal or ureteral calculus confirmed by non-contrast computed tomography (CT); (ii) patients were admitted to the ED during the month of Ramadan, the preceding month and the following month. The exclusion criteria were as follows: (i) non-fasting Muslim patients or patients with an unclear fasting status; (ii) patients diagnosed with RC due to causes other than urolithiasis; and (iii) patients clinically diagnosed with RC who did not undergo confirmatory abdominal non-contrast CT.
The study protocol was approved by the Ethical Committee of Hillel Yaffe Medical Centre (approval no. 0071-20 HYMC; 31.05.2020). Due to the retrospective nature of this paper the local ethics committee approved a consent waiver and as such, cases included in the analysis were not required to provide an informed consent. The reporting of this study conforms to STROBE guidelines. 16
Data extraction
All case files of adult patients with a documented primary diagnosis of RC confirmed by non-contrast CT scans due to renal or ureteral calculus who had been admitted to the ED during the month of Ramadan, the preceding month and the following month during a 10-year period over the years 2009–2019 were included in the analysis. Included patients were reviewed consecutively from the electronic medical records. The reviewed patients were recorded anonymously, devoid of any identifiable patient details, preserving their privacy rights.
Patient characteristics included medical history and clinical data. In addition, all urgent endoscopic and urological interventions (e.g. DJS insertion) were documented. The diagnosis of RC was made based on the physician’s clinical judgement according to classical clinical features, medical history, physical examination and laboratory tests (i.e. complete blood count, biochemical tests and spot urine testing). Non-contrast abdominal CT was collected for all patients. Each diagnosis made by the physician was subsequently validated by the non-contrast CT scan.
Relevant sociodemographic variables were noted and each patient was coded by religious status (Muslim/non-Muslim [Jewish, Christian and Druze]). Fasting verification was routinely documented on the nursing and medical staff admission report.
The patients were divided into two groups: fasting Muslim patients and non-fasting non-Muslim patients. The two groups were matched for age and sex. The incidence of RC hospital admissions during the study years was compared between the two groups in the month preceding Ramadan, during Ramadan, and in the month following Ramadan.
Statistical analyses
All statistical analyses were performed using IBM SPSS Statistics for Windows, Version 27.0 (IBM Corp., Armonk, NY, USA). The cohort size was determined by the number of patients admitted to the ED between 2009 and 2019 with a confirmed diagnosis of RC as described previously. Continuous data are presented as mean ± SD and range. Categorical data are presented as n (%). Independent t-test and χ2-test were used to compare patient characteristics according to their religion. A P-value < 0.05 was considered statistically significant.
Results
A total of 2781 patients with a primary diagnosis of RC secondary to urolithiasis were included in this retrospective case–control analysis. The mean ± SD age of the overall study cohort was 53 ± 11 years (range, 18–102 years) and the majority of the patients were male (1975 of 2781 patients; 71.0%). One hundred and thirty-three Muslim patients were excluded from the analysis due to unclear fasting status. A total of 977 (35.1%) patients were admitted during Ramadan, 880 (31.6%) were admitted during the pre-Ramadan month and 924 (33.2%) during the post-Ramadan month (Table 1). In total, 1014 (36.5%) fasting Muslim patients and 1767 (63.5%) non-fasting non-Muslim patients were admitted during the study period. All Muslim patients that were included in the study reported fasting almost every day during the month of Ramadan. Over the entire 10-year study period, one-third of the admissions during the Ramadan months were of fasting Muslim patients and two-thirds were of non-fasting non-Muslim patients (318 of 977 patients [32.5%] versus 659 of 977 patients [67.5%], respectively). Similar results were seen during the pre-Ramadan months over the 10-year study period (305 of 880 patients [34.7%] versus 575 of 880 patients [65.3%], respectively). There was a significant increase in the number of admissions of fasting Muslim patients (391 [42.3%]) compared with non-fasting non-Muslim patients (533 [57.7%]) in the pre-Ramadan to post-Ramadan months (P < 0.001).
Demographic and clinical characteristics of patients (n = 2781) included in a retrospective case–control study to investigate the impact of Ramadan fasting on the incidence of renal colic stratified according to their fasting status.
Data presented as mean ± SD or n (%).
Patient admission was stratified according to religion (Table 2). This increase in the number of admissions between the pre- and post-Ramadan months reached statistical significance, as did the increase in the number of admissions between the Ramadan and post-Ramadan months (P < 0.01 for both comparisons).
Admissions of patients (n = 2781) included in a retrospective case–control study to investigate the impact of Ramadan fasting on the incidence of renal colic stratified according to their fasting status.
Fasting Muslim group versus non-fasting non-Muslim group; χ2-test was used to compare the groups.
A total of 685 of 2781 patients (24.6%) with a mean ± SD age of 55 ± 17 years (range, 18–93 years; 442 of 685 [64.5%] males) required an urgent DJS insertion during the 10-year study period. Of them, 252 (37.8%) patients were fasting Muslims and 433 (63.2%) were non-fasting non-Muslims. During the pre-Ramadan months, 230 of 880 (26.1%) patients needed a DJS insertion, of whom 76 (33.0%) were fasting Muslims (Table 3). During the Ramadan month, 245 of 977 (25.1%) patients needed a DJS insertion, of whom 87 (35.5%) were fasting Muslim patients. During the month following Ramadan, 210 of 924 (22.7%) patients needed a DJS insertion, of whom 90 (42.9%) were fasting Muslim patients. There were no significant differences between the two groups in terms of the proportions of patients requiring a DJS insertion during the Ramadan, pre-Ramadan and post-Ramadan months.
Rates of double J stent (DJS) insertion of patients (n = 2781) included in a retrospective case–control study to investigate the impact of Ramadan fasting on the incidence of renal colic stratified by their fasting status.
Data presented as number of DJS insertions/total admissions (%).
NS, no significant between-group difference (P ≥ 0.05); χ2-test was used to compare the groups.
Discussion
This retrospective case–control study primarily aimed to investigate the correlation between Ramadan fasting and an increased risk for RC ED admissions. Contrary to the expectations, fluid restrictions and prolonged fasting during the month of Ramadan did not lead to an increased incidence of RC admissions during the month of Ramadan. Nevertheless, the findings of the current study demonstrated a significant increase in admissions due to RC (up to 42.3%) in the month following Ramadan in fasting Muslim patients (P < 0.001). The findings were compared between a fasting Muslim group and a non-fasting non-Muslim reference group, all of whom were being treated in a urology department at an Israeli medical centre during the 10-year study period. Furthermore, in a secondary research analysis, no significant association was observed between the rates of DJS interventions during the month preceding Ramadan, the month of Ramadan itself and the month after Ramadan.
Health-related aspects of Ramadan fasting and its significance on a wide range of diseases have been extensively studied. 6 Several previous studies that reported a relationship between Ramadan fasting and urinary stone formation have shown controversial results.4–6,12,13 Many of the previous reports concluded that fasting during the month of Ramadan did not increase the risk for developing urinary stones compared with the pre- and post-Ramadan non-fasting months.4,10,12–15
A 10-year study conducted in Saudi Arabia in 237 patients diagnosed with RC secondary to urinary stones found no significant difference in the frequency of patients admissions between the Ramadan and non-Ramadan months. 12 In a 3-year study from Lebanon, the rates of ED admissions due to RC among 514 patients were not significantly different during the Ramadan month compared with the pre- and post-Ramadan months. 17 In contrast to these previous reports, two other studies reported a significant association between Ramadan fasting and RC, demonstrating a significant increase (P < 0.05) in ED admissions only during the first 2 weeks of the Ramadan fast.4,15 A 10-year study conducted in southern Israel reported a significant increase in RC-related ED admissions, which were higher during the first 2 weeks of the Ramadan fast among 4517 Muslim patients (relative risk [RR] 1.267, 95% confidence interval [CI] 1.031, 1.502), while no such association was observed among the 13 646 Jewish patients (RR 1.061, 95% CI 0.885, 1.238). 4 Moreover, this increased risk for RC signified a 26% increase in mean weekly admissions due to RC during this period compared with the entire year. 4 Both previous studies pointed to early renal adaptation capability, even during extreme conditions of a prolonged fast, as a plausible explanation.4,15 A study conducted in Bahrain among 809 RC patients, with similar findings to the current study, found significantly higher admissions due to RC during the Ramadan and post-Ramadan months compared with the pre-Ramadan month. 14
The occurrence of the Ramadan holy days during the summertime and in hot climates, with extended fasting time and a heightened risk of daytime dehydration, may influence the rate of urinary stone formation. 7 Two different studies, one conducted in Saudi Arabia and the other conducted in Iran, reported a significant association between elevated RC admission rates and the hot season.11,13 Nevertheless, their findings demonstrated no significant differences between the rate of urinary stone colic during the month of Ramadan and the non-Ramadan months.11,13
A plausible mechanism for the current study’s principle finding of no correlation between fasting during Ramadan and the prevalence of RC, but a notable increase in the number of cases of RC in the month following Ramadan, could result from a delayed clinical impact of fasting on renal stone formation. This delayed effect might arise from prolonged exposure to fasting and reduced urine output, leading to a buildup of minerals that does not manifest immediately but becomes apparent at a later time. Another possible explanation for the differences that were observed in the current study compared with other reports could be differences in climate conditions. While the current research was conducted in Israel, known for its Mediterranean climate, even slight variations in geographical location can significantly alter climate conditions. For example, this current study focused on fasting Muslims in the northern region of Israel, whereas a previous study was conducted in Southern Israel, which is characterized by a hotter, more desert-like climate. 4 Other reports were based in Saudi Arabia, Iran or other Muslim countries that might also have different climates to the geographical setting of the current study.5,12–15
This current study’s secondary analysis assessed the effect of Ramadan fasting on the necessity for urgent DJS insertion due to RC and showed no significant impact. Kidney drainage by DJS insertion is recommended by current guidelines to reduce the risk of obstruction and deterioration of renal function in the treatment of renal calculi in patients at an increased risk of complications. 18 The current study found only one published report on stenting in the urinary system during the month of Ramadan, which reported that Muslim patients had significantly fewer invasive procedures, including ureteral stenting compared with non-fasting Jewish patients during the holy month of Ramadan (n = 121 [2.7%] versus n = 550 [4.0%], respectively; P < 0.001). 4 Unlike their findings, the current study found no statistically significant increase in urgent DJS insertion among Muslim patients during either the Ramadan, pre- or post- Ramadan months and the rate of DJS insertion was comparable with that of the non-fasting non-Muslim group.
The strength of the current study lays in the large number of patients that were include and the 10-year study period. In addition, unlike the majority of previous reports that were conducted in Muslim countries,5,10,12–14,17 this current study included a reference group of non-fasting non-Muslim patients. Furthermore, the current analysis only included Muslim patients that had verified documentation of them fasting during the Ramadan month.
This current study had several limitations. First, it was a retrospective study that was undertaken at a single medical institution. The retrospective design meant that the study was susceptible to selection bias, which should be considered when interpreting the results. Secondly, the clinical manifestation of kidney stones can be sporadic and they might not necessarily be present during the specific time frame of the fasting period; subsequently developing sometime after fasting resulting in RC at a later date. Therefore, the incidence of acute RC admissions that this current study sought to measure might not be fully represented in the findings.
In conclusion, these current findings did not demonstrate an association between Ramadan fasting and an increased incidence of RC ED admissions or urgent DJS insertions when fasting Muslims were compared with non-fasting non-Muslim groups in Israel. These current results did show a statistically significant increase in RC ED admissions during the post-Ramadan month among the fasting Muslim patients, which might indicate a possible role of fasting in the late presentation of RC. In addition, this current study did not demonstrate any significant increase in the rate of urgent DJS insertions between the pre- and post-Ramadan months among the fasting Muslim patients during the 10-year study period.
Footnotes
Author contributions
G.L. contributed to protocol/project conceptualization, data investigation, methodology, data analysis and manuscript writing/editing. M.M. contributed the methodology, data validation, data analysis and manuscript writing/editing. M.A. and Y.A. contributed to visualization and manuscript writing/editing. R.R. contributed to protocol/project conceptualization, supervision and manuscript editing. The work reported in the paper has been performed by the authors unless clearly specified in the text.
Declaration of conflicting interest
The authors declare that there are no conflicts of interest.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
