Risk of kidney injury following oral phosphosoda bowel preparations

Case reports and case series suggest a potential link between oral sodium phosphosoda used in preparation for outpatient colonoscopy and kidney injury, but controlled studies are lacking. We performed a case-control study nested within a cohort of patients with baseline serum creatinine ≤1.5 mg/dL who underwent outpatient colonoscopy. We defined a case of kidney injury as a rise in serum creatinine >0.5 mg/dL and/or 25% between values obtained during the 6 months prior and during the 6 months following colonoscopy (n = 116). We found that exposure to phosphosoda was not more common among patients with incident kidney injury (adjusted odds ratio 0.70; 95% Cl 0.44-1.11), and sensitivity analyses that considered other definitions of kidney injury did not suggest a different conclusion. Therefore, despite a plausible link, the current data do not support an association between oral phosphosoda and kidney injury at 6 months follow-up among patients with baseline serum creatinine ≤1.5 mg/dL. Further studies are warranted to validate and generalize our findings.