Change in renal function after sodium phosphate preparation for screening colonoscopy

Aim: To investigate the changes in renal function at 1224 mo in patients following sodium phosphate (NaP) preparation for screening colonoscopy. Methods: We carried out a retrospective study on the results from patients who received health checkup ser vices as part of an employerprovided wellness program performed between August 2006 and May 2008 and who were followed up for 1224 mo. Prior to screening colonoscopy, 224 patients underwent bowel cleansing with NaP (NaP group) and 113 patients with polyethylene glycol (PEG group). The control group comprised 672 agematched patients. We compared the changes in the creatinine levels and the glomerular filtration rates (GFRs) from baseline to 1224 mo between the NaP, PEG, and control groups using twoway repeated measured analysis of variance. In addition, multivariate linear regression analysis was performed to assess the risk factors for a decreased GFR. Results: The baseline mean serum creatinine level in the NaP, PEG, and control groups was 1.12 ± 0.15, 1.12 ± 0.16, and 1.12 ± 0.15 mg/dL, which increased to 1.15 ± 0.15, 1.15 ± 0.18, and 1.15 ± 0.15 mg/dL, respectively, after 1224 mo. The baseline mean GFR in the NaP, PEG, and control groups was 69.0 ± 7.7, 68.9 ± 8.0, and 69.6 ± 6.7 mL/min per 1.73 m2, which decreased to 66.5 ± 7.8, 66.5 ± 8.3, and 67.4 ± 6.4 mL/min per 1.73 m2, respectively, after 1224 mo. The changes in serum creatinine levels and GFRs were not significantly between the NaP, PEG, and control groups (P = 0.992 and P = 0.233, respectively). Using multivariate linear regression analysis, only the baseline GFR was associated with the change in GFR (P < 0.001). Indeed, the bowel preparations were not associated with the change in GFR (P = 0.297). Conclusion: NaP bowel preparation in subjects with normal renal function was not associated with renal injury, and NaP can thus be used safely for screening colonoscopy.