#3386 PROTON-PUMP INHIBITORS AND SERUM CONCENTRATIONS OF UREMIC TOXINS IN PATIENTS WITH CHRONIC KIDNEY DISEASE

Abstract

Abstract Background and Aims Use of proton-pump inhibitors (PPIs) is common in patients with chronic kidney disease (CKD). PPIs and many uremic toxins (UTs) are eliminated by a kidney tubular organic anion transporter system. In a cross-sectional study, we sought to evaluate the association between PPI prescription and serum concentrations of various UTs. Method We studied a randomly selected subgroup of participants in the CKD-REIN prospective cohort (adult patients with a confirmed diagnosis of CKD and estimated glomerular filtration rate (eGFR) <60ml/min/1.73m²) with available frozen samples collected at baseline. PPI prescription was recorded at baseline. Serum concentrations of 10 UTs were measured using a validated liquid chromatography tandem mass spectrometry technique. Multiple linear regression was performed, with the log UT concentration as the dependent variable. Results Of the 680 included patients [median age: 68 years; median eGFR: 32 ml/min/1.73 m2], 31% had PPI prescriptions at baseline. Patients using PPIs had higher levels of certain UTs in comparison to other patients, including total and free indoxyl sulfate (IS), total and free p-cresylsulfate, total and free p-cresylglucuronide (PCG), phenylacetylglutamine (PAG), free kynurenine, and free hippuric acid. After adjustment for baseline comorbidities, number of co-prescribed drugs and laboratory data including eGFR, associations between PPI prescription and elevated serum concentrations of free and total IS, free and total PCG, and PAG remained significant. Conclusion Our results indicate that PPI prescription is independently associated with serum UT retention. These findings indicate a potential mechanism for side effect of PPIs in CKD patients that will need to be confirmed by longitudinal studies.