The estimated 10-year cumulative incidence, according to the above formula, of a first-episode of urolithiasis is shown in Table 2. Calibrated after adjustment for life expectancy, the overall standardized lifetime prevalence rate can be estimated to be 11.5%: 12.9% in men and 9.8% in women (Table 2).
Urolithiasis is a common and significant health problem that appears to be increasing in frequency in recent decades in both men and women. Previous studies have shown that the prevalence of urolithiasis varies greatly with patient age, gender, race, and geographic region.9, 10, 11, 12 And the annual incidence of urolithiasis has been reported to range from 0.5% to 1.5% in western countries.13, 14 The prevalence of urolithiasis has been reported to be 4.7% to 8.8% in western countries. Many other studies have demonstrated a yearly increase in the prevalence of urolithiasis.9, 15 However, previous studies have been limited by their local areas and a dependency on the patients' subjective memory regarding the urolithiasis episode. To overcome these limitations, Bae et al.16 recently conducted a study with a larger national sample size and estimated that the annual incidence of upper tract urolithiasis was 457 cases per 100,000 population. However, that study did not evaluate patient follow-up or recurrence.
It was difficult to estimate the lifetime prevalence of urolithiasis because we could not determine the number of subjects who had an episode of urolithiasis prior to the study period. However, we were able to calculate the recurrence rate from this retrospective cohort data. We were able to estimate the risk of recurrence based on the assumption that the recurrence risk is similar at each time point. In our study, we were able to calculate the overall 5-year recurrence rate from the NHIS sample cohort dataset. The overall 10-year recurrence rate was estimated to be 38.1%, lower than that of a previous study from Taiwan.17 While few studies have provided reliable information on the recurrence rate, a previous case series indicated that stones form in 30% to 40% of untreated patients within 5 years after the initial episode.18 2b1af7f3a8