Title:

Comparison of Oxidative Stress and Preservation of Residual Kidney Function Between Incremental and Standard Peritoneal Dialysis in Incident Patients at the Regional General Hospital No. 58 and HGZ/UMF 21 of the Mexican Institute of Social Security (IMSS) in León, Guanajuato

BACKGROUND:

Peritoneal dialysis (PD) employs hypertonic dextrose-based solutions to remove toxins and excess fluids. This exposure promotes mitochondrial overproduction of reactive oxygen species (ROS), triggers inflammation, and may accelerate the decline of residual kidney function (RKF), leading to complications such as peritonitis, peritoneal fibrosis, and technique failure. Although more biocompatible solutions are available, their high cost and limited accessibility restrict their use in our setting.

Incremental peritoneal dialysis (IPD), in contrast to standard peritoneal dialysis (SPD)-which typically involves four daily exchanges with full-dose dialysis-uses reduced dialysis doses tailored to RKF, thereby decreasing glucose exposure.

The primary aim of this study was to compare the effects of IPD versus SPD on oxidative stress, inflammation, and the preservation of residual kidney function in incident peritoneal dialysis patients at the Regional General Hospital No. 58 in León, Guanajuato.

MATERIALS AND METHODS:

A prospective, longitudinal, single-center, open-label, randomized clinical trial will be conducted. Incident peritoneal dialysis patients at the Regional General Hospital No. 58 and Gneral Hospital of Zone Numbre 21 of the Mexican Institute of Social Security (IMSS) who meet the inclusion criteria and provide informed consent will be randomly assigned to either the standard or incremental peritoneal dialysis group.

Acute-phase reactants will be measured at baseline and at 3, 6, 9, and 12 months. Oxidative stress will be assessed via baseline and end-of-study malondialdehyde levels. Dialysis and urine Kt/V will be evaluated betwen 6 weeks and 3 moths and 6, 9, and 12 months. Appropriate statistical analyses will be performed thereafter.

Eligible incident peritoneal dialysis (PD) patients from two IMSS hospitals in León, Guanajuato (HGR No. 58 and HGZ-MF No. 21) will be enrolled after confirmation of adequate Tenckhoff catheter placement and written informed consent. Baseline demographic and clinical data will be collected from medical records and physical examination, including age, sex, marital status, educational level, anthropometric parameters (weight, height, body mass index), and volume status assessed by physical examination using the Godet edema scale.

Laboratory evaluations will be performed in blood and urine. Fasting venous blood samples will be obtained for complete blood count, serum chemistry, electrolytes, lipid profile, inflammatory markers (albumin, ferritin, C-reactive protein, D-dimer), and viral serology (HBV, HCV, HIV). Oxidative stress will be assessed in serum by measuring thiobarbituric acid-reactive substances (TBARS) as an index of malondialdehyde concentration using a standardized spectrophotometric method.

Residual renal function will be assessed at baseline and during follow-up (45 days, and 3, 6, 9, and 12 months) by estimated glomerular filtration rate (CKD-EPI equation), 24-hour urine volume, and 24-hour creatinine clearance. Solute clearance adequacy (renal and peritoneal Kt/V) will be measured at 1.5-3 months, 6 months, and 12 months. Peritoneal membrane transport characteristics will be evaluated at month 3 using the Peritoneal Equilibration Test (PET).

Participants will be randomized in a 1:1 ratio to Incremental Peritoneal Dialysis or Standard Peritoneal Dialysis using block randomization (blocks of four). Glucose exposure will be quantified based on dialysate glucose concentration and number of exchanges, expressed as bags per year. Catheter-related complications and infection-free catheter survival will be monitored throughout the 12-month follow-up. After completion of follow-up, patients will continue PD according to their treating nephrologist's prescription.

Inclusion Criteria:

CKD adults starting on PD FKR ≥2 mL/min Urine Volumen ≥500 mL/24 hrs Type 2 Diabetes, Hypertension and unknown cause of CKD

Exclusion Criteria:

Self-reported smoking or active use of illicit drugs. Patients with liver disease. Patients with glomerulonephritis. Patients with a history of previous renal replacement therapy (hemodialysis or kidney transplant).

Database and Informed consent

IPD and supporting documents will be available starting 6 months after publication of the primary results and will remain accessible for 5 years.

Access to de-identified IPD will be granted to qualified researchers with a methodologically sound proposal, subject to IRB approval and a signed data use agreement. Requests must be submitted via email to the principal investigator. Data will be shared through secure electronic means.