Change in renal function after sodium phosphate preparation for screening colonoscopy

Abstract

To investigate the changes in renal function at 12-24 mo in patients following sodium phosphate (NaP) preparation for screening colonoscopy. We carried out a retrospective study on the results from patients who received health check-up services as part of an employer-provided wellness program performed between August 2006 and May 2008 and who were followed up for 12-24 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 age-matched patients. We compared the changes in the creatinine levels and the glomerular filtration rates (GFRs) from baseline to 12-24 mo between the NaP, PEG, and control groups using two-way repeated measured analysis of variance. In addition, multivariate linear regression analysis was performed to assess the risk factors for a decreased GFR. 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 12-24 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 m(2), which decreased to 66.5 +/- 7.8, 66.5 +/- 8.3, and 67.4 +/- 6.4 mL/min per 1.73 m(2), respectively, after 12-24 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). 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.