Determining the true burden of kidney stone disease

The incidence and prevalence of kidney stones have increased over the past four decades. However, the diagnosis of ‘kidney stone’ can range from an incidental asymptomatic finding of limited clinical significance to multiple painful episodes of ureteral obstruction with eventual kidney failure. Some general strategies may be useful to prevent the recurrence of kidney stones. In particular, greater attention to kidney stone classification, approaches to assessing the risk of recurrence and individualized prevention strategies may improve the clinical care of stone formers. Although there have been some advances in approaches to predicting the recurrence of kidney stones, notable challenges remain. Studies of kidney stone prevalence, incidence and recurrence have reported inconsistent findings, in part because of the lack of a standardized stone classification system. A kidney stone classification system based on practical and clinically useful measures of stone disease may help to improve both the study and clinical care of stone formers. Any future kidney stone classification system should be aimed at distinguishing asymptomatic from symptomatic stones, clinically diagnosed symptomatic stone episodes from self-reported symptomatic stone episodes, symptomatic stone episodes that are confirmed from those that are suspected, symptomatic recurrence from radiographic recurrence (that is, with radiographic evidence of a new stone, stone growth or stone disappearance from presumed passage) and determine stone composition based on mutually exclusive categories. Available data suggest that the prevalence and incidence of kidney stones is increasing; however, much of this variation might result from differences in approaches used to identify stone formers. This Review describes the need for a classification system to facilitate use of consistent terminology and enable meaningful comparisons of the burden of kidney stone disease across different populations. Key points Kidney stones can range from an asymptomatic incidental finding with limited clinical significance to a painful recurrent disorder with substantial morbidity. The prevalence and incidence of kidney stones has increased worldwide, but some of this increase is due to improvements in medical imaging with increased utilization of CT. Classifying stone formers according to their clinical presentation and stone composition can help to predict the risk of future symptomatic stone episodes and aid personalizat