Objective: Previous research on the life expectancy of persons with American Spinal Injury Association (ASIA) Impairment Scale Grade D spinal cord injury has considered them as a large homogenous group, making no functional or medical distinctions. This study sought to (1) determine how survival in this group depends on ambulatory function and the extent of bowel or bladder dysfunction, (2) compute life expectancies for various subgroups, and (3) examine whether survival has improved over time.
Design: Data were from 8,206 adults with ASIA Impairment Scale Grade D spinal cord injury in the Spinal Cord Injury Model Systems database who were not ventilator dependent and who survived more than 1 yr after injury. There were a total of 114,739 person-years of follow-up and 1,730 deaths during the 1970-2011 study period. Empirical age- and sex-specific mortality rates were computed. Regression analysis of survival data with time-dependent covariates was used to determine the effect of risk factors, to test for a time trend, and to estimate mortality rates for subgroups. Life expectancies were obtained from life tables constructed for each subgroup.
Results: The ability to walk, whether independently or with an assistive device, was associated with longer survival than wheelchair dependence. The need for an indwelling catheter, and to a lesser extent intermittent catheterization, was associated with increased mortality risk. Persons who walked unaided and who did not require catheterization had life expectancies roughly 90% of normal. Those who required a wheelchair for locomotion had life expectancies comparable with that in paraplegia, less than 75% of normal. No time trend in survival was found.
Conclusions: Life expectancy of persons with ASIA Impairment Scale D spinal cord injury depends strongly on the ability to walk and the need for catheterization.