Icodextrin Postpones the Shift of Low Dose to Full Dose Dialysis in the First Year of Incremental Peritoneal Dialysis

Specific details of Treatment to be used in conducting study:

The objective of this study is to investigate the effects of icodextrin on postponing the shift of lowdose at the initial dialysis to full dose dialysis in the first year of PD in patients with incremental PD. The specific details of treatment/intervention are as follow:

1. Incident PD patients of SYSU PD center who meet the inclusion criteria will be recruited. All participants will be 1:1 randomized to the ICO (icodextrin) arm and CON (control) arm. Day 0 was defined as 6 weeks ± 4 weeks after CAPD initiation.
2. The patients in both the ICO and CON arms are prescribed Dextrose 2 L x 3 for incremental peritoneal dialysis during the first year.
3. Both arms patients will be followed every 2 months for fluid status by bioimpedance analysis (BIA). An extracellular water /total body water (ECW/TBW) ≥ 0.40 is defined as overhydration (OH).
4. The OH patients in the ICO arm will be prescribed icodextrin (Extraneal) for long night dwell to improve fluid overload till their re-measurement of ECW/TBW < 0.40 or edema disappeared. The OH patients in the CON arm will be prescribed hypertonic Dextrose solution for long night dwell to improve fluid overload till their ECW/TBW < 0.40 or edema disappeared. This means that all the patients in both arms will use the same three bags of glucose solution per day at the beginning of the study. When patients have overhydration [(ECW/TBW) ≥ 0.4 or edema], the long night dwell glucose solution in the ICO group will be replaced by Icodextrin till ECW/TBW < 0.40 or edema disappeared. While patients with overhydration in the CON group will increase glucose concentration till their ECW/TBW < 0.40 or edema disappeared. (The advantage of icodextrin has been proven in patients with ultrafiltration failure, high transport peritoneal membranes, and diabetics as compared to standard glucose based dialysate.
5. Both arms patients will be followed every 2 months for clinical manifestations, medication, and PD prescription (PD modality, dosage, and dialysate glucose concentration) during routine visits.
6. Patients in the both arms will be transferred to full dose dialysis if they have the following clinical manifestations: refractory fluid overload, unexplained nausea or vomiting, hyperkalemia, metabolic acidosis, uncontrollable hyperphosphatemia, uremia, neuropathy, pericarditis, sleep disorder, restless legs syndrome, pruritus, intractable anemia.
7. If necessary, medications will be used for treatment of hypertension, anaemia, chronic kidney disease-mineral and bone disorder, malnutrition, hyperlipidemia, the acid-base imbalance, electrolyte disturbance, etc.
8. If heart failure happened, patients in both the ICO and CON arms will be performed intermittent PD (IPD).

Efficacy Assessments:

1. Baseline data and follow-up information will be collected. Baseline demographics includes age, sex, primary kidney disease, body mass index (BMI), and diabetes. Baseline laboratory data include GFR, creatinine clearance (CrCl), urea clearance weekly (Kt/Vurea), ultrafiltration volume, systolic blood pressure (SBP), diastolic blood pressure (DBP), 24-h urine volume, serum albumin, serum creatinine (Scr), blood urea nitrogen (BUN), uric acid (UA), hemoglobin, intact parathyroid hormone (iPTH), total cholesterol, triglycerides, calcium, and phosphorus.
2. Both 24-hour urine and PD effluent will be collected at the same time each day to calculate Kt/Vurea, creatinine clearance, normalized protein clearance rate, and measured GFR using Adequest 2.0 software (Baxter Healthcare).
3. The adequacy of renal and peritoneal solute clearance will be assessed by total weekly Kt/V calculated using standard methodology. CAPD patients will receive Kt/V test every 2-4 months.
4. Peritoneal function and biomarkers for peritoneal biocompatibility will be performed: the peritoneal equilibration test (PET), sodium dip, CA125 and interleukin- 6 (IL-6) in effluent of patients in both groups.
5. All baseline data will be collected at day 0. Both arms patients will be followed up every 2 months for clinical manifestations, medication, and PD prescription (PD modality, dosage, and dialysate glucose concentration) during routine visits.
6. Events such as the episodes of peritonitis, transferring to hemodialysis (HD), anuria, cardiovascular disease(CVD), hospitalization, all cause death and CVD death will be recorded.
7. Quality of Life (Medical Outcomes Study 36-Item Short From Survey) will be measured and collected at the Day 0 and at the end of the study.

Statistical Methods:

1. Sample size: A preliminary analysis using database of our PD center showed: A total of 193 subjects (of which 97 are in group1 and 96 are in group 2) achieves 80% power at a 0.0500 significance level to detect a difference of 0.1900 between 0.6200 and 0.8100--the proportions surviving in groups 1 and 2, respectively. This corresponds to a hazard ratio of 0.4408. The proportion of patients lost during follow up was 0.0500. These results are based on the assumption that the hazard rates are proportional. Accordingly, 194 subjects (97 in each group) were intended to be included in the study.
2. Primary Endpoint Analysis: Primary endpoint (event that transferring from a low dose dialysis to full dose dialysis in the first year of incremental PD) analyses are on the basis of the intent-to-treat approach. Patient event-free survival will be calculated using the Kaplan-Meier method, and differences between different groups are assessed by log-rank tests. Considering patients transferred to other modalities as censoring (competing end points), the Fine and Gray proportional subhazards model will be used to create a competing risk model.
3. Secondary endpoint(s) analysis:

Secondary endpoints include first episode of peritonitis, anuria, CVD free survival, first hospitalization, technique failure (transferring to HD), all-cause and cardiovascular mortality, which will be evaluating using the Kaplan-Meier method, and differences between different groups are assessed by log-rank tests. Considering patients transferred to other modalities as censoring (competing end points), the Fine and Gray proportional subhazards model will be used to create a competing risk model. Quality of Life (PF, RP, BP, GH, VT, SF, RE, MH, PCS, MCS, total score of SF-36) will be evaluated using an unpaired Student's t test or Mann-Whitney U test.