Patients with Urinary Incontinence Appear More Likely to Develop Upper Urinary Tract Stones: A Nationwide, Population-Based Study with 8-Year Follow-Up

This study aimed to investigate associations between primary urinary incontinence and development of upper urinary tract stones in a nationwide population in Taiwan. Data of 1,777 adults with primary urinary incontinence and 26,655 controls (groups A, B, and C) without urinary incontinence at study inception were retrieved from the National Health Insurance System database in Taiwan and were analyzed retrospectively. No enrolled subjects had previous diagnosis of upper urinary tract stones or spinal cord injury. All subjects were followed through end of 2009, with a minimum follow-up of 8 years. A greater percentage of study subjects (334/1777, 18.8%) developed upper urinary tract stones than that of control groups A (865/8885, 9.7%) and B (888/8885, 10%), and C (930/8885, 10.5%) (all p-values < 0.0001). Urinary incontinence was associated with significantly increased risk of developing urinary tract stones (HR 1.99, 95% CI, 1.70–2.34, p < 0.001). Age and metabolic syndrome status were both associated with developing upper urinary tract stones (both p-values < 0.0001). After adjusting for metabolic syndrome, regression analysis showed that urinary incontinence was still associated with a significantly increased risk of developing upper urinary tract stones (HR 1.99, 95% CI = 1.76–2.26, p < 0.0001). Long-term follow-up of Taiwanese patients with primary urinary incontinence suggests that urinary incontinence is associated with a significantly increased risk of developing upper urinary tract stones. Study findings suggest that physicians treating patients with urinary incontinence should give attention to early detection of upper urinary tract stones.