Impact of ramadan fasting on bone mineral metabolism in hemodialysis: a multi-center prospective observational cohort study

The effects of Ramadan fasting on biochemical parameters and bone mineral metabolism in maintenance hemodialysis (MHD) patients remain insufficiently studied. This study aimed to evaluate the impact of Ramadan fasting on biochemical indices and bone turnover biomarkers in patients undergoing chronic hemodialysis. This multi-center prospective observational cohort study included 138 adult hemodialysis patients recruited from four dialysis centers in Dakahlia Governorate, Egypt. Eligible patients were aged 18–85 years, on stable hemodialysis for at least six months, and had no recent changes in treatments affecting mineral bone disease parameters. Patients were classified according to fasting behavior into three groups: non-fasting, fasting on non-dialysis days only, and fasting throughout Ramadan. Clinical data, dialysis characteristics, interdialytic weight gain, and intradialytic complications were recorded. Blood samples were obtained at the beginning and end of Ramadan to assess biochemical parameters and bone metabolism biomarkers, including alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BSAP), fibroblast growth factor-23 (FGF23), sclerostin, α-Klotho, and tartrate-resistant acid phosphatase 5b (TRAP5b). Statistical comparisons of biochemical and bone-biomarker changes between baseline and post-Ramadan time points were performed among the three groups. Baseline demographic and clinical characteristics were largely comparable among groups. No significant differences were observed in dialysis-related complications, including hypotension and hypoglycemia, before or after Ramadan. Serum potassium decreased to a comparable extent across all three groups, with no significant between-group difference, while serum sodium and albumin showed modest increases in patients fasting throughout Ramadan. Calcium, phosphorus, magnesium, and iPTH levels remained stable across groups. Among bone biomarkers, an unadjusted between-group difference in BSAP change was observed ( P = 0.041), with an increase in non-fasting patients contrasting with stable or slightly decreased levels in fasting patients; this difference did not persist after adjustment for age, sex, BMI, and dialysis vintage (adjusted P = 0.229). FGF23, sclerostin, and TRAP5b increased, whereas Klotho decreased across all groups, with no significant between-group differences before or after adjustment. No clinically significant bone-related adverse events were reported. No short-term safety signal was detected in this selected, clinically stable hemodialysis cohort under medical supervision, although the study was not designed or powered to evaluate safety. Fasting was associated with stable biochemical parameters and a relatively stable bone turnover profile, without worsening mineral bone disease markers. Larger controlled studies with longer follow-up are needed to clarify the long-term skeletal effects of Ramadan fasting in this population.