Fig. 1

Flow Diagram of Study Population Enrolment. Between January 1, 2010, and December 31, 2018, a total of 18,239 patients with spinal cord injury (SCI) were identified and matched with 54,717 controls without SCI in a 1:3 ratio based on age, sex, and index year. Of these, 696 patients with SCI and 2,689 controls were younger than 40 years and were excluded, along with 136 patients with SCI and 43 controls with a history of traumatic brain injury, 54 patients with SCI and 76 controls with Parkinson’s disease, and 347 patients with SCI and 1,012 controls with missing data for matched variables. Finally, the study included 7,182 patients with SCI and 24,844 controls in the analysis. SCI = spinal cord injury; TBI = traumatic brain injury; PD = Parkinson’s disease.