The Influence of Low Phosphorus in Hemodialysis Patients

Consuming high levels of dietary phosphate and poor adherence of phosphate-binding-therapy might induce hyperphosphatemia in the hemodialysis (HD) patients. Therefore, the risks of Chronic Kidney Disease-related Mineral and Bone Disorders (CKD-MBDs) and inflammation will be increased. This double blind and intervention randomized controlled trial study will be designed to investigate the hypothesis that if low phosphorus meals decrease serum phosphorus concentration and inflammatory indicators. A total of 80 HD patients in the HD center of Shuang Ho Hospital will be recruited and be assigned to low phosphorus meal group (LP group) and control group randomly before one-week-washout period. The subjects of LP group and control group will consume low phosphorus meals and standard meals respectively. During washout period and study period, all subjects will continue to consume their regular breakfast and take one tablet of calcium carbonate with meal. All data will be collected at baseline, one week after the washout period, and the end of the 7-days-study period. The indicators are including dietary contents, phosphate binder administration, indicators of dialysis adequacy, nutritional indicators, blood lipid indicators, biochemical indicators, CKD-MBDs indicators, and inflammation indicators. Data were analyzed by Statistical Product and Service Solutions program version 18. Paired t-test, Student's t-test, Pearson correlation coefficient and Logistic regression will be used. P \< 0.05 will be considered as statistically significant.

Study Design and Subjects:

This study was design as a randomized, double-blind control trail. A total of 80 HD patients were recruited from the HD center of Taipei Medical University-Shuang Ho Hospital in Taiwan. The inclusion criteria were including ≧20 years old and non vegetarian. The exclusion criteria are including liver dysfunction, cancer and pregnancy.

Dietary Intervention:

All subjects followed their usual diets but took one tablet of calcium carbonate as phosphate binder per meal for the first week washout diet. After washout diet, subjects were assign to control or study group randomly and entered to the study period for one week. The diets of the study group were low phosphorus ( LP group), but the dietary phosphorous levels of the control group were not modified. During the study period, all subjects including LP group and control group still kept their usually accustomed behavior about regular breakfast and also took one tablet of calcium carbonate as phosphate binder with every breakfast meal. The LP group and control group replaced daily lunch and dinner with low phosphorus and standard meals respectively and should not take any phosphate binder during the study period for one week.

For controlling the volumes of proteins, phosphorus and calcium easily, the main courses of both of the study and the control meals were made by a central kitchen. All of the meals contained 3 exchanges of protein (25 g) and 1 exchange of vegetable. There were 5 main courses for the both diets. The proteins of the study meals had been removed by an average 20 -30% of the phosphorus through boiling the meats before cooking process. But the boiling method did not process for the control meals. Every meal including all the study and the control meals contained one tablet of calcium carbonate. As a consequence, the additional phosphate binders should not be taken while eating the study meals. The subjects had to prepare carbohydrate by themselves, and they could choose any source of carbohydrate as their wants.

Data Collection:

The personal characteristics and the anthropometry data were collected at baseline. All data were collected at baseline, one week after the washout period, and the end of the 7-days-study period. The indicators were including dietary contents, phosphate binder administration, dialysis adequacy, nutritional indicators, blood lipid indicators, biochemical indicators, CKD-MBDs indicators, and inflammation indicators.

Eligibility Criteria:
Inclusion Criteria:

* Hemodialysis patients, ≥ 20 years of age

Exclusion Criteria:

* ≥ 80 years of age, liver cirrhosis, cancer, pregnancy, vegetarian