Urinary tract stone is a highly recurrent disease, with reported recurrence rate around 50% within 5–10 years. While various studies have explored risk factors for recurrence, there is limited research on Taiwan's local population. Additionally, the impact of age groups and regional variations, possibly impacted by microclimatic factors, remains unclear. This study aims to identify risk factors for urinary tract stone recurrence in Taiwan using data from the National Health Insurance Research Database (NHIRD).

This retrospective cohort study analyzed NHIRD data from 2011/01 to 2021/12 and was approved by the National Cheng Kung University Hospital Institutional Review Board (A-ER-109-567). Urinary tract stone diagnoses were identified using ICD-9 codes 592-594 and ICD-10 codes N20-N22. Recurrence was defined as a patient receiving an initial stone diagnosis and subsequently requiring extracorporeal shock wave lithotripsy (ESWL), an emergency department visit, or hospitalization for urinary tract stones at least 3 months later. Demographics, regional distribution, and potential risk factors were assessed.

A total of 551,698 patients were identified, including 342,168 males and 209,530 females. Females were more likely to visit the emergency department, while males were more frequently treated with ESWL or hospitalized for surgical intervention. This suggests that males are more proactive in seeking treatment, whereas females tend to be more conservative. Residents of the Outlying Islands had the highest rates of emergency department visits and ESWL treatments, indicating significant impact of urinary tract stone on this population. However, they had the lowest hospitalization rates, possibly due to limited hospital resources and challenges in accessing healthcare services in these areas. Overall, males sought intervention more frequently than females. The highest urinary tract stone rates were observed in the Outlying Islands, followed by Eastern, Central, Northern, and Southern Taiwan. The 50s age group had the highest healthcare utilization. Common risk factors for healthcare utilization included hypertension, dyslipidemia, hyperuricemia, gout, chronic kidney disease (CKD), and hyperparathyroidism.

Our study revealed significant regional and demographic disparities in urinary tract stone recurrence in Taiwan. Residents of Taiwan’s outlying islands exhibited a markedly higher overall recurrence rate, including increased risks of ESWL retreatment and emergency department revisits, yet had a significantly lower risk of hospitalization compared to those on the main island. Age played a crucial role, with recurrence rates rising after 40 years old, peaking around 50 years old, and then declining. Among chronic conditions, hyperparathyroidism showed the strongest association with recurrence. These findings highlight the need for region-specific and age-adapted prevention strategies to reduce urinary tract stone recurrence.