Many people think the worst part of a colonoscopy is the preparation -- clearing your entire large intestine of fecal matter. Your doctor will give you detailed instructions about the cleansing process, which can take two days or more. Now a study reported in The Archives of Internal Medicine suggests that some bowel cleaning preparations can cause kidney damage in some adults.
If you're scheduled for a colonoscopy, be sure to check the bowel cleansing preparation you use. Oral sodium phosphate (OSP) -- a popular choice that's available over the counter -- can cause severe chronic kidney damage in older users.
Researchers compared the records of 286 older adults (age 58 to 78) who used OSP before a colonoscopy with those from 125 individuals who had not used it. The OSP group had a measurable decrease in their kidney function (as measured by creatinine level and glomerular filtration rate [GFR]) within one year of using the product.
In the OSP group, the mean creatinine level increased from 0.92 mg/dL at baseline to 1.04 mg/dL at one year (1.5 mg/dL was the laboratory's upper limit for normal). In addition, the group had an 8% reduction in their total GFR at one year.
Those who had not had a colonoscopy had a much slower decline in kidney function, which is consistent with normal aging. At baseline, their mean creatinine level was 0.92 mg/dL and it rose to 0.96 mg/dL at one year, and the total GFR decreased by only 1%.
Bottom line: If you're older or have chronic kidney disease and are scheduled for a colonoscopy or use OSP for other health reasons, speak with your doctor about alternatives, such as polyethylene glycol (PEG) solutions.
Reported in Archives of Internal Medicine (Volume 168, page 593).
