Epidemiology of Nephrolithiasis and Chronic Kidney Disease Project

  • Changing urinary stone type with recurrent episodes

    Patients experiencing their third or fourth stone episodes are more likely to have uric acid, brushite, struvite or cystine stones than are those experiencing their first or second episode.

Changing urinary stone type with recurrent episodes
  • Risk of urinary stone recurrence

    After a first stone event, patients with uric acid and struvite stones have a second stone sooner than do those with calcium oxalate or hydroxyapatite stones.

Risk of urinary stone recurrence
  • Risk of end-stage renal failure (ESRD)

    After their first symptomatic event, patients with urinary stones are more likely to develop ESRD than are matched controls without stones.

Risk of end-stage renal failure (ESRD)

Principal investigator:
Andrew D. Rule, M.D.

The O'Brien Urology Research Center's Epidemiology of Nephrolithiasis and Chronic Kidney Disease Project is aimed at predicting risk of kidney stone recurrence and subsequent development of chronic kidney disease.

Researchers working on the project recently developed a model to predict the risk of a second kidney stone event after the first. This model was made into an app that can be accessed online.

Additionally, evidence gathered by Dr. Rule has demonstrated that nephrolithiasis is a risk factor for subsequent development of chronic kidney disease. The Epidemiology of Nephrolithiasis and Chronic Kidney Disease Project investigates underlying pathogenic factors to explain this association.

The project takes advantage of a unique resource available at Mayo Clinic to enumerate and collate nearly all health care records in Olmsted County, Minnesota, the Rochester Epidemiology Project. A population-based historical cohort and a prospective cohort of patients with first-time kidney stones and matched controls are being studied. In addition, new patients and matched controls have been recruited for this study from Mayo Clinic's campus in Jacksonville, Florida, for the prospective cohort study by William E. Haley, M.D.

Results from the Epidemiology of Nephrolithiasis and Chronic Kidney Disease Project will better characterize the natural history of nephrolithiasis and help identify which category of nephrolithiasis patients might require more aggressive treatment strategies to prevent recurrent stone events or loss of kidney function over time.

An additional benefit of this project is collection of blood, urine and DNA samples in addition to detailed clinical history and exam findings, which can be used for other epidemiologic studies as well as for future genotype-phenotype studies. For example, information from patients in this project was used for the center's Genetic Variation of Oxalate Transporters in CaOx Nephrolithiasis Pilot Project.

Significance to patient care

Kidney stones are common, affecting 10 percent of the adult population in the U.S. Besides pain (often described as the worst ever experienced), stones lead to costly surgical interventions, loss of work and the long-term complication of kidney failure, requiring dialysis or transplantation.

Preventing future painful stone passage is the primary concern of kidney stone patients, about 30 percent of whom will have recurrence within 10 years of their first stone event.

Currently, physicians cannot identify which patients are at high risk of recurrence. Thus, there is a critical need to develop a model for predicting recurrence. Without such a model, the current practice of waiting for patients to have recurrent painful stone events before starting preventive therapy leads to unnecessary suffering and expense. On the other hand, treating every kidney stone patient with aggressive dietary and medical interventions is expensive and potentially harmful in those who have a low risk of recurrence.