Fasting during the month of Ramadan among patients with chronic kidney disease: renal and cardiovascular outcomes

BACKGROUND Fasting during the month of Ramadan is a religious obligation for Muslims who represent 20% of the world population. This study explores the safety of fasting for a whole month among patients with chronic kidney disease (CKD) with the possible risk of dehydration and hyperviscosity leading to deterioration of kidney functions and vascular thrombosis. METHODS We followed CKD patients with stable kidney function who chose to fast during the month of Ramadan. A group of nonfasting CKD patients served as controls. Serum creatinine was recorded at the beginning of the month, after 1 week of fasting, at the end of the month and 3 months later. Patients were followed for major adverse cardiovascular events (MACE). RESULTS A total of 131 CKD patients were recruited and included in two groups: fasting and nonfasting (mean baseline estimated glomerular filtration rate 27.7, SD 13 and 21.5, SD 11.8 mL/min/1.73 m2, respectively). A rise of serum creatinine was noted during fasting in 60.4% of patients by Day 7 and was associated with intake of renin angiotensin aldosterone system antagonists [relative risk (RR) 2, P = 0.002]. Adverse cardiovascular events were observed in six patients in the fasting cohort and were associated with a rise of serum creatinine after 1 week of fasting (P = 0.009) and the presence of pre-existing cardiovascular disease (RR 15, P = 0.001); the latter association was confirmed by logistic regression analysis. Only one event was recorded in the nonfasting group, P = 0.036. CONCLUSIONS MACE occurred more frequently among fasting CKD patients with pre-existing cardiovascular disease and were predicted by an early rise of serum creatinine.