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 m(2), 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.