Intermediate bioelectrolyte changes after phospho-soda or polyethylene glycol precolonoscopic laxatives in a population undergoing health examinations.

BACKGROUND Colonoscopy is a common procedure for diagnosing and screening colon cancer and other bowel-related diseases. Many studies have pointed out that using phospho-soda as a bowel preparation can cause obvious electrolyte abnormalities or acute kidney injury. Nonetheless, there are few studies related to its prevalence and risk factors in the population undergoing health examinations. Our aim was to compare the biochemical and electrolyte changes after using two commonly used bowel preparation regimens in this population. METHODS In this retrospective study, we collected data about participants who, before a screening colonoscopy, used oral phospho-soda laxatives in 2006, and those who used polyethylene glycol-based laxatives in 2005. Several serum biochemical and electrolyte profiles were compared between the two groups. Additional risk factors of hyperphosphatemia, a well-known side effect of phospho-soda, were also derived. RESULTS We enrolled a total of 2270 participants (1321 in 2005; 1449 in 2006). The basic demographic data of the two groups were not statistically different. Nonetheless, between the two groups, some serum biochemical and electrolytic data differed significantly: in those using oral phospho-soda laxatives, we found a higher prevalence of hyperuricemia, hypocalcemia, hypokalemia, hypernatremia and hyperphosphatemia. Further analyses showed that using oral phospho-soda laxatives was a risk factor for hyperphosphatemia; conversely, being male was a protective factor. CONCLUSION Oral phospho-soda laxatives indeed influence the biochemical and electrolyte profiles of persons undergoing health examinations. One should be careful when interpreting bioelectrolytic data while using phospho-soda as a bowel preparation.