According to this study:
* Glomerular filtration rates often decline in elderly patients who use oral sodium phosphate solutions to prepare for bowel endoscopy.
* Widespread use of such solutions should be discontinued in this population.
Oral sodium phosphate solution, a cleansing agent commonly used in preparing for bowel endoscopy, is associated with decreased glomerular filtration rates (GFRs) in elderly patients with normal creatinine levels.
In this retrospective case- control study, 286 patients with creatinine levels of less than 1.5 mg/dL who used oral sodium phosphate solutions before bowel endoscopy from 1998 through 2005 were assessed for changes in renal function six months and one year after the procedure.
Use of these preparations was associated with a significant decline in GFR from 79 mL/min/1.73 m2 at baseline to 73 mL/min/1.73 m2 at six months. The control group's GFR of 76 mL/min/1.73 m2 at baseline remained stable at six months. The GFR further decreased, albeit less dramatically, at one year. In terms of absolute GFR, over the one-year period, the study group's total GFR fell by 8%, compared with 1% in the control group. Use of angiotensin- converting enzyme inhibitors or angiotensin receptor blockers, the presence of diabetes, and the group effect significantly influenced the GFR at six months.
The use of oral sodium phosphate solutions should be avoided in the elderly. Alternatives such as polyethylene glycol preparations are available and should be considered, particularly in patients with stage 3 to 5 chronic kidney disease undergoing elective colonoscopy.