Medication is an additional source of phosphate intake in chronic kidney disease patients

Background and aims: Hyperphosphatemia increases the risk of cardiovascular morbidity but the use of medicines as a source of phosphate has not been investigated yet. This study aims to explore the use of absorbable phosphate-containing drugs in CKD patients. Methods and results: Incident CKD patients were identified within the Arianna database (containing data from 158,510 persons in Caserta (Southern Italy) registered with 123 general practitioners) from 2005 to 2011. Drugs prescribed to these patients were classified as phosphate-containing based on the summary of product characteristics (SPC), PubChem and Micromedex. The number and duration of prescriptions for these drugs as well as the overall intake of phosphate were estimated.Out of 1989 CKD patients, 1381 (70%) were prescribed 266 medicinal products containing absorbable phosphate over a median follow-up of 6 years (interquartile range (IQR) = 5.2-6.0). Most patients were prescribed ATC A (650; 47.1%) and C (660; 47.8%) phosphate-containing drug products targeting the gastrointestinal and cardiovascular system for a median of 232 (IQR: 56-656) and 224 (IQR: 56-784) days respectively. Conclusions: Several medications, especially chronically prescribed ones, contain absorbable phosphate. This study's findings confirm the relevance of medicines as a phosphate source for the first time.