Do people with inflammatory bowel disease have higher risks of kidney stones?

Research confirms that patients with inflammatory bowel disease (IBD) face a greater risk of developing kidney stones compared to the general population. This risk is particularly high for those with Crohn's disease or those who have had extensive bowel surgeries. The condition often stems from malabsorption and chronic inflammation within the gut.

What the research says

Historical studies show that the prevalence of symptomatic kidney stones is higher in IBD patients than in the general population ⁴. This risk is typically seen in patients who have undergone extensive small bowel resection or have persistent severe small bowel inflammation ⁴. Kidney stones in these patients often arise from chronic inflammation, changes in intestinal absorption, or intestinal malabsorption ⁴.

The risk is more closely associated with Crohn's disease than with ulcerative colitis, primarily because of malabsorption issues ⁴. In Crohn's disease, patients with kidney stones have a 10-fold higher risk of developing chronic kidney disease than those without stones ⁵. Specific risk factors for developing high oxalate levels in urine include steatorrhea (fatty stools) and frequent stools ⁶.

A lack of a specific gut bacteria called Oxalobacter formigenes is a major factor. This bacteria is absent in 91% of children with Crohn's disease who developed high oxalate levels, but present in all controls ⁶. The absence of this bacteria allows the body to absorb too much oxalate from food, leading to stone formation ⁶.

What to ask your doctor

• Do I have specific risk factors for kidney stones, such as frequent stools or fatty stools?
• Should I get tested for the gut bacteria Oxalobacter formigenes?
• How can I adjust my diet to reduce oxalate absorption if I have Crohn's disease?
• What are the signs of kidney stones I should watch for given my IBD history?