Association Between Oral Sodium Phosphate Bowel Preparations and Kidney Injury: A Systematic Review and Meta-analysis

Background

Case reports and series have suggested an association between oral sodium phosphate bowel preparations and kidney injury. Results of analytic studies have been mixed.

Study Design

Systematic review and meta-analysis.

Setting & Population

Patients receiving sodium phosphate bowel preparations (or comparators) in anticipation of colonoscopy.

Selection Criteria for Studies

Primary data reports of controlled studies of the effects of oral sodium phosphate versus comparator on kidney function.

Predictor

Receipt of oral sodium phosphate bowel purgative.

Outcomes

Random-effects pooled odds ratio for kidney injury in oral sodium phosphate–treated patients.

Results

Seven studies met criteria for inclusion. Significant heterogeneity existed in the populations under study (colonoscopy indication, baseline kidney function, and demographics), methods used (control group and use of prophylactic hydration), definition of kidney injury used (timing and magnitude), and results observed. The pooled odds ratio for kidney injury in oral sodium phosphate–treated patients ranged from 1.08 (95% confidence interval, 0.71 to 1.62) to 1.22 (95% confidence interval, 0.77 to 1.92). No obvious study- or patient-level factors that explained interstudy heterogeneity were identified.

Limitations

Few studies, each of limited quality.

Conclusions

Based on existing data, it is not possible to discern whether there is an association between receipt of oral sodium phosphate and kidney injury. Future investigation should be aimed at clarifying this association and examining the roles of prophylactic hydration and baseline kidney function on any imposed risk. Future work would be greatly enhanced by a standardized definition of incident kidney injury.

Index Words: Sodium phosphate, kidney injury, colonoscopy, systematic review, meta-analysis