Overall procedures for urolithiasis increased significantly between 1998 and 2004. Total discharges related to urinary stone disease increased from 129.1 to 169.9 per 100,000 (p < 0.01). Utilization among men increased from 86.6 to 105.5 per 100,000 (; 22% increase), while utilization by women increased from 42.5 to 64.4 per 100,000 (; 52% increase). Although procedure use in both genders increased (p < 0.01 for both groups), the rate of growth in women was significantly greater than in men (p < 0.01). The ratio of men to women discharged after urinary stone surgery decreased from 2 in 1998 to 1.6 in 2004.
Overall Admissions for Upper Urinary Tract Stone Disease
Utilization of inpatient services was relatively flat between 1998 and 2004. Overall admissions increased from 35.5 per 100,000 to 38.3 per 100,000 (; 8% increase, p = 0.05). This small increase in inpatient services was attributable solely to utilization by female patients. Inpatient admissions in women increased from 12.5 to 16.3 per 100,000 (30% increase, p < 0.01), but no increase was observed in men (23.0 to 22.0 per 100,000; p = 0.7964). Utilization increased significantly faster in women than in men (p = 0.01). The ratio of men to women treated in the inpatient setting decreased from 1.8 in 1998 to 1.3 in 2004. Between these two time periods, the distribution of patients receiving a definitive therapy (i.e. ESWL, percutaneous nephrolithotomy, ureteroscopy) was stable in men and women. In 1998, 53% of men received definitive therapy compared to 53% in 2004. In women, the percentage of patients who received definitive therapy remained at 49% in both 1998 and 2004.
Inpatient Admissions for Upper Urinary Tract Stone Disease
Hospital outpatient department utilization increased 24.3% between 1998 and 2004 from 84.2 to 104.7 per 100,000 (). While the use of the hospital outpatient department increased both among women (27.0 to 38.9, 44% increase; p < 0.01) and men (57.2 to 65.8, 15% increase; p = 0.01), the rate of increase was faster in women (p < 0.01). The ratio of men to women treated in the hospital outpatient department decreased from 2.1 in 1998 to 1.69 in 2004.
Hospital Outpatient Department Utilization for Upper Urinary Tract Stone Disease
Ambulatory surgery center utilization increased rapidly from 1998 to 2000, but then stabilized (). Significant growth of this surgical environment occurred in both men (6.4 to 17.7 per 100,000, 176% increase; p < 0.01) and women (2.9 to 9.3 per 100,000, 202% increase; p < 0.01 for both), and no difference existed for growth in ASC use comparing the two groups (p = 0.44). The ratio of men to women for ASC use in stone disease treatment was 2.2 in 1998 and 1.9 in 2004.
Ambulatory Surgery Center Utilization for Upper Urinary Tract Stone Disease
No changes were seen in the study period in the mean age, or age distributions, of the discharges treated for stone disease. The mean age in the cohort was 52 at the time of discharge. The mean age of the men in the cohort was 54, and for women it was 50. These mean ages did not vary between 1998 and 2004. The age distribution of women also did not change during the study period. In 1998, 36% of the surgeries were in women aged 40 to 60. By 2004, 40% of the surgeries were in this age group. In 1998, 31% of surgeries for stone disease were in patients younger than 40 years of age. By 2004, this population represented 29% of the total cohort of women treated surgically for stone disease.