Trends in the Incidence and Etiology of Non-Traumatic Spinal Cord Injury in Korea: A Nationwide Population-Based Study From 2007 to 2020

BACKGROUND: Although patients with non-traumatic spinal cord injury (NTSCI) have distinct epidemiological characteristics compared to those with traumatic spinal cord injury, no previous study has reported the incidence of NTSCI on a national scale in Korea. In this study, we examined the trend in incidence of NTSCI in Korea and described the epidemiological characteristics of patients with NTSCI using nationwide insurance data. METHODS: National Health Insurance Service data were reviewed for the period from 2007 to 2020. The International Classification of Diseases, 10th revision, was used to identify patients with NTSCI. Inpatients with newly diagnosed NTSCI on their first admission during the study period were included. Crude incidence was calculated using the annual number of NTSCI cases divided by the mid-year population estimates. Age-specific incidence was calculated by dividing the number of cases in 10-year age groups by the total number of individuals in that age group. Age-adjusted incidence was calculated using direct standardization. Annual percentage changes were calculated using Joinpoint regression analysis. The Cochrane-Armitage trend test was conducted to examine the trends of NTSCI incidence according to the types or etiologies of NTSCI. RESULTS: The age-adjusted incidence of NTSCI increased continuously from 24.11 per million in 2007 to 39.83 per million in 2020, with a significant annual percentage change (4.93%, P < 0.05). The age-specific incidence for those in their 70s and 80s or older was the highest and rapidly increased from 2007 to 2020. According to the types of paralysis in NTSCI, the proportion of tetraplegia decreased, whereas those of paraplegia and cauda equina increased significantly from 2007 to 2020. The proportion of degenerative diseases was the largest among all etiologies and increased significantly during the study period. CONCLUSION: The annual incidence of NTSCI in Korea is increasing significantly, particularly among older adults. As Korea is one of the countries with most rapidly aging population in the world, these results have significant implications, indicating that preventive strategies and sufficient rehabilitation medical services are warranted for the population of older adults.