Impact of Ramadan fasting on kidney function and related outcomes in chronic kidney disease and kidney transplant recipients: a systematic review and meta-analysis

Abstract

Objectives: Ramadan fasting is an Islamic religious practice involving abstinence from food and drink from dawn to sunset. Its consequences on kidney-relevant outcomes in patients with chronic kidney disease (CKD) and kidney transplant recipients remain unclear.

Design: Systematic review and meta-analysis.

Data sources: MEDLINE, Embase, Global Health, CINAHL (EBSCOhost), Scopus, Web of Science and Google Scholar were searched up to 18 September 2023.

Eligibility criteria: We included observational studies among non-dialysis CKD and kidney transplant recipients who fasted during Ramadan and examined changes in kidney function.

Data extraction and synthesis: Standardised methods were used by two independent reviewers to screen, select and extract data. Outcomes included changes in serum creatinine (SCr), estimated glomerular filtration rate (eGFR), proteinuria, blood pressure, electrolytes and adverse events-all pre- and post-Ramadan. Results were pooled using random effects modelling.

Results: We included 32 observational studies with a total of 2592 participants. 21 studies reported on participants with CKD and 11 studies reported on kidney transplant recipients (studies variably including non-fasting control arms). Meta-analysis of 25 studies revealed that Ramadan fasting was not associated with changes to SCr for the following groups according to study design: CKD with a non-fasting arm (mean difference (MD)=0.82 µmol/L; 95% CI -7.22, 8.86; I²=38%); transplant with a non-fasting arm (MD=-0.17 µmol/L; 95% CI -2.50, 2.15; I²=0%) and CKD without a non-fasting arm (post-pre MD=13.84 µmol/L; 95% CI -3.78, 31.47; I²=88%). For transplant studies without a non-fasting arm, lower SCr was associated with the post-Ramadan period (post-pre MD=-5.40 µmol/L; 95% CI -10.78, -0.02; I²=0%). In the 18 studies that reported on eGFR, fasting during Ramadan was not associated with an effect on eGFR for any of the groups.

Conclusion: We report inconsistent effects of Ramadan fasting on kidney function in CKD or kidney transplantation. Results should be interpreted with caution due to the significant limitations of the underlying studies.

Keywords: Acute renal failure; Chronic renal failure; Nephrology; Systematic Review.

Figure 1. Flow diagram of study selection. CKD, chronic kidney disease.

Figure 2. Forest plot of serum creatinine and estimated glomerular filtration rate in studies with a non-fasting arm. CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; MD, mean difference; SCr, serum creatinine. MD (ie, the difference between the change in pre- and post-Ramadan measurements in the fasting arm and the change in pre- and post-Ramadan measurements in the non-fasting arm).

Figure 3. Forest plot of serum creatinine and estimated glomerular filtration rate in studies without a non-fasting arm. CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; MD, mean difference; SCr, serum creatinine. MD (ie, the difference between pre- and post-Ramadan measurements).