Changes in gender distribution of urinary stone disease

To explore using population-based data the extent to which gender-specific rates of stone disease are changing. Historically, stone disease has been more common among men than women. However, differential changes in dietary intake patterns, fluid intake, and obesity in men and women may cause shifts in stone disease incidence and prevalence.

The State Ambulatory Surgical Database and the State Inpatient Databases were queried for procedures related to renal colic or urolithiasis. Population-based rates of utilization were calculated for the years 1998-2004 by gender. Poisson regression models were fit to measure changes in utilization rates over time.

Of the 107,411 discharges for stone disease, 41,272 (38%) occurred in women. Service utilization increased in both men and women (86.6-105.5 and 42.5-64.4 per 100,000; P <.01 in both). However, the growth rate in women outpaced men (P <.01). Rates of outpatient (57.2-65.8 and 27.0-38.9 per 100,000; P <.01) and ambulatory surgery center utilization (6.4-17.7 and 2.9-9.3 per 100,000 men and women; P <.01) increased significantly in men and women, but inpatient utilization only increased in women (12.5-16.3 per 100,000; P <.01).

Resource utilization for stone disease continues to increase. Most of this increase appears to be due to an increase in disease among women. Increasing obesity, dietary changes, or decreased fluid intake may be contributing to the rapid increase in stone disease treatments in women.