Researchers have developed a new tool to predict the likelihood that patients with a first-time kidney stone will have a second episode of the extremely painful condition. The tool, known as a nomogram, may help physicians determine which patients will benefit from medication or preventive measures.
Published online today in the Journal of the American Society of Nephrology, the Recurrence of Kidney Stone nomogram evaluates 11 patient characteristics to calculate the risk of recurrence. In addition to age, sex, and race, they include whether imaging had been performed and the stone’s composition and location.
Led by Andrew Rule, MD, of the Mayo Clinic in Rochester, Minnesota, the researchers developed the tool based on their analysis of medical records from all adults treated for their first stone in Olmstead County, Minnesota, from 1984 to 2003. Of the 2239 patients studied, 707 had a recurrence through 2012. About 11% of patients had a recurrence 2 years after their first stone, and 20% had another stone 5 years after the first one. The recurrence rate reached 31% after 10 years and 39% after 15 years.
Characteristics that predicted a higher risk of recurrence included younger age, male sex, white race, family history of kidney stones, visible blood in the urine, stones made of uric acid rather than calcium, an obstructing stone in the renal pelvis, and any additional nonobstructing stones.
Kidney stones are common, affecting about 6% to 9% of the population. “If we knew which patients were at high risk for another symptomatic kidney stone, then we could better advise patients on whether to follow stone prevention diets or take medications,” Rule said in a statement.
“At the same time, patients who are at low risk of having another kidney stone may not need restrictive diets and medications,” he added.
In an accompanying editorial, Brian Eisner, MD, of Massachusetts General Hospital in Boston, and David Goldfarb, MD, of the VA New York Harbor Healthcare System in New York City, noted that the nomogram should be tested prospectively in additional patients with kidney stones. “Whether additional variables can be added to increase the usefulness of this tool will be of interest in the future,” they wrote.
Categories: Renal Diseases