A 3-day diary of dietary protein and calorie intake by serum phosphate concentration and binder use in hemodialysis patients

Introduction: The use of phosphate binders to control hyperphosphatemia may allow diets less restricted in protein and calories for maintenance hemodialysis (MHD) patients. The study compared intakes of protein, calorie and phosphate among MHD patients with different serum phosphate concentrations, taking into account binder use. The hypothesis was that low serum phosphate would be associated with low intakes of protein and calories only in patients not on binders. Methods: A cross-sectional study of 443 patients enrolled in the Prospective Study of the Prognosis of Chronic Hemodialysis Patients (PROHEMO) in Salvador, Brazil, with stratified sampling on serum phosphate: <= 3.0 (n = 41), 3.5-5.5 (n = 328) and >= 7.0 mg/dL (n = 74). A 3-day diet diary was used to determine dietary intakes. Results: Approximately 49.0% confirmed binder use. Covariate-adjusted linear regression showed that associations between dietary intakes and serum phosphate were modified by the binder use. In patients not on binders, protein intake was >20% lower for serum phosphate <= 3.0 mg/dL compared to higher concentrations. Also in those not on binders, calorie intake was >30% lower for serum phosphate <= 3.0 mg/dL compared to >= 7.0 mg/dL. Differences in dietary intakes by serum phosphate were virtually absent in patients on binders. Conclusions: The results are consistent with the hypothesis that low serum phosphate is associated with low protein and calorie intake only among MHD patients not on binders. This study supports recommendations to prevent hyperphosphatemia in MHD patients by adequate combination of binder use and selection of foods restricted in phosphors but not severely restricted in protein and calories.