Background: Carpal tunnel syndrome (CTS), one of the most common peripheral neuropathies of the upper extremity, has been studied for decades regarding its epidemiology and associated medical conditions. We conducted a large-scale, age- and gender-matched study from an Asian population database to investigate the relationship between the incidence and the demographic characteristics.

Methods: A retrospective cohort study using data of National Health Insurance Research Database (NHIRD) was conducted. One million enrollees in Taiwan was
used to identify 9442 patients with CTS and 37768 randomly selected controls, in a control-case ration of 4:1. Diagnoses of CTS were ascertained from January 1, 2003, to December 31, 2012. Sociodemographic and medical characteristics were evaluated to assess the correlation with CTS.

Results: Annual incidence of CTS were around 0.4% during the 10-year-period in Taiwan, with higher incidence rate in female gender and middle age of group (50-59 years old). Among the medical conditions, previous wrist injuries, obesity, gout and RA were associated to CTS most significantly.

Conclusion: CTS has presented a relatively constant incident rate in Taiwan of modern era. Female gender with middle age seemed to have the highest incidence during a 10-year period from 2003 to 2012. Among the risk factors of CTS, previous wrist injuries, obesity, gout and RA were demonstrated to be the most significantly correlated comorbidities.