Login to Access Video or Poster Abstract: MP95-09
Sources of Funding: none

Introduction

Demographic studies on renal calculi have suggested an increasing incidence of nephrolithiasis. Although these studies have used large national databases, none have examined data from within the last decade and have suggested that the closing gender gap is due to an increased incidence of calculi in females. The purpose of this study was to examine the most recent data from the Nationwide Inpatient Sample database to investigate the recent trends of gender and race in this pervasive disease.

Methods

Patient data of 459,823 discharges from 2000 to 2013, with a primary International Classification of Diseases, 9th revision principal diagnosis code of 592.0 (calculus of kidney) or 592.1 (calculus of ureter) were included in the study. Only patients with a designation of either “male” or “female” were included in the study. Racial groups were divided into White, Black, Hispanic, Asian, Native American, or other/not recorded. Trend analysis was performed, and fit lines were generated using a linear regression model to compute statistical significance. A subgroup analysis, with respect to gender, was performed for each race.

Results

The 459,823 discharges included 243,223 from men and 216,600 from women. Within the 13-year study period, total discharges for renal and ureteral calculi decreased by 19.1% with a statistically significant, 1.7% decrease in incidence per year (p =0.0001). Calculi in men decreased by an average of 2.2% per year for a total of 30.5% decrease in incidence in the study period (p <0.0001). However, the incidence of calculi in women was variable without any significant trend. Sub-group analysis by race revealed that renal and ureteral calculi were more common in Black females and Hispanic females when compared to their male counterparts. The incidence of stones grew by an average of 2.7% per year in Black women (p< 0.002) and 4.6% per year in Hispanic women (p< 0.0001). This resulted in a 50.4% increase in incidence in each group between 2000 and 2013.

Conclusions

While data from earlier years had suggested that the incidence of stone disease was increasing, our analysis of recent data show that the incidence of renal and ureteral calculi resulting in medical intervention (evaluation by a physician, admission, etc.) is decreasing. This trend is attributable to a decrease in stone disease in men, resulting also in a decreased male-to-female ratio of stone disease from 1.3:1 to about 1:1. This study also reveals interesting trends in the racial demographics of stones with Black and Hispanic women now experiencing up to 50% more stone disease than their male counterparts.

Funding

none