Hyperthyroidism and female urinary incontinence: a population-based cohort study

The imbalanced autonomic nervous system present in hyperthyroidism may cause lower urinary tract symptoms. Urinary incontinence (UI) is the most bothersome lower urinary tract symptom; however, in the literature, reports regarding urinary dysfunction and/or incontinence among hyperthyroid patients are scarce. This population-based cohort study aimed to examine the relationship between hyperthyroidism in women and the risk of developing UI in Taiwan.

This study used data from the Longitudinal Health Insurance Database. For this study, 10,817 female patients diagnosed with hyperthyroidism from 2001 to 2005 were recruited together with a comparison cohort of 54,085 matched enrollees who did not have a history of hyperthyroidism. All patients were tracked for a 3-year period from their index date to identify those who had a subsequent UI. The stratified Cox proportional hazards models were used to compute the risk of UI between study and comparison cohorts.

During the follow-up period, of 64,169 patients, 173 (1·60%) from the hyperthyroidism group and 560 (1·04%) from the comparison group, had a diagnosis of UI. The regression analysis showed that, after adjusting for monthly income, geographic region, urbanization level of the community in which the patient resided, obesity and hysterectomy, patients with hyperthyroidism were more likely to have UI during the 3-year follow-up period than the comparison patients (hazard ratio = 1·54; 95% CI = 1·30-1·83; P < 0·001).

Our results suggest an increased risk of UI in patients with hyperthyroidism at the 3-year follow-up.