Relationship of American Spinal Injury Association Impairment Scale Grade to Post-injury Hospitalization and Costs in Thoracic Spinal Cord Injury

BACKGROUND: The lifetime economic burden of thoracic spinal cord injury (SCI) is known to be high, but evidence of variability of costs in relation to the American Spinal Injury Association Impairment Scale (AIS) grade is limited. OBJECTIVE: To estimate lifetime economic costs of hospitalization by AIS grade in thoracic SCI. METHODS: Using SCI Model Systems data from January 2000 to March 2016 from the National Spinal Cord Injury Statistical Center, we estimated mean total annual days of all-cause hospitalization by AIS grade among persons with thoracic SCI, based on assessments 1, 5, and 10 yr post-injury. We combined this information with secondary cost data and projections of life expectancy to estimate lifetime economic costs of hospitalization by AIS grade in persons aged 35 yr at time of thoracic SCI. Future costswere discounted to present value at 3% annually. RESULTS: One year post-injury, mean total annual days of hospitalization ranged from 2.1 for persons with AIS-D injuries to 5.9 for those who were AIS-A. Similar differences were noted 5 and 10 yr post-SCI. The estimated net present value of expected lifetime costs of hospitalization following thoracic SCI at age 35 yr was $321 534, $249 514, $188 989, and $68 120 (2015 US$) for AIS-A, AIS-B, AIS-C, and AIS-D injuries, respectively. CONCLUSION: Persons with less severe thoracic SCI, as reflected in AIS grade, spend fewer days in hospital over their lifetimes, leading to lower costs of inpatient care. Therapies improving AIS grade following thoracic SCI may provide cost savings in addition to addressing substantial unmet need.