Data analysis
The collected data were processed using the software SPSS version 26. The data were analyzed by descriptive statistical methods such as computing numerical measures (mean and standard deviation) and inferential tests. The independent t-test and the chi-square test were used to compare FCEPG and CG in terms of demographic variables. The independent t-test was also used to compare FCEPG and CG in terms of knowledge of phosphate control, adherence to DRPI, adherence to medication, and serum phosphorus level. The GLM-repeated measures ANOVA was used to make intra-group comparisons between the three measurement stages: Baseline, Follow-Up1 (one month after FCEP), and Follow-Up2 (three months after FCEP). For all tests and analyses, the significance level was considered to be 0.05.