Ankylosing spondylitis (AS) is a seronegative spondyloarthropathy that increases the risk of spinal fractures and spinal cord injury. Previous reports have shown that the lower cervical spine is the most common site for fractures among those with AS. This study was designed to better understand the incidence and type of spinal fractures in the AS population.

Data were obtained from a national inpatient sample of patients with AS and spinal fractures from 2005 to 2011. This retrospective, cohort study characterized spinal fractures by region and spinal cord injury based on ICD-9 codes. Spinal fractures were further classified by treatment group and by incidence of adverse events.

Of the 939 patients hospitalized with a fracture, 498 were cervical, 393 were thoracic, 171 were lumbar, 14 were sacral and 123 were multiple in region. Of these, 6.6% died during hospitalization. A spinal cord injury occurred in 198 of the 939 patients, with two thirds occurring as a result of cervical, and one third as the result of thoracic, fractures. Among the 276 patients experiencing adverse events during hospitalization, urinary tract infection was the most common, and intubation the second most common.

This study of patients with ankylosing spondylitis found that those hospitalized with a vertebral fracture are at high risk for inpatient complications and mortality.