High Prevalence of Cervical Myelopathy among Hip Fracture Patients

Abstract

Hip fractures are devastating injuries for the elderly and an increasing burden to the healthcare system. Cervical spondylotic myelopathy (CSM), as a common cause of disability, instability, and falls in the elderly population, places patients at risk for hip fracture, and myelopathic patients are associated with increased complications after hip surgery. Myelopathy's relationship with hip fractures and impact, however, is not well understood. This study sought to 1) determine the prevalence of CSM among hip fracture patients and 2) hypothesized that hip fractures in CSM patients were associated with greater complexity and costs. In this institutional review board-exempt study, Medicare 1) hip fracture and 2) CSM patients between 2004 and 2014 were identified using the PearlDiver Patient Records Database (PearlDiver Technologies, Inc., CO) with International Classification of Diseases, Ninth Revision, (ICD-9) and Common Procedural Terminology codes. The prevalence of CSM within hip fracture patients was calculated, as was the incidence of hip fractures within CSM patients during this period. Hip fracture patients with CSM were compared with non-CSM hip fracture patients by age, medical comorbidities, average charges/payments, and average lengths of stay (LOS). Hip fracture patients with CSM who underwent cervical surgery were also compared with those who did not undergo cervical surgery, both before and after hip fracture. Statistical analysis with t-test and chi-squared test was performed, with statistical significance set at P < 0.05. Total 22,884 of 2,309,972 hip fracture patients (1.0%) from 2004 to 2014 also had CSM, representing approximately 9900 cases per million persons, higher than previous estimates of the CSM incidence in the general population. These 22,884 hip fracture patients were 4.6% of 496,939 patients with CSM diagnosed during this period, representing a hip fracture incidence of 419 cases per 100,000 persons/year, also higher than previous estimates of hip fracture incidence in the overall population. Hip fracture patients with CSM were significantly younger (P < 0.001) but had significantly greater incidence of hypertension, coronary artery disease, stroke, obesity, tobacco use, diabetes, and osteoporosis (P < 0.001) than non-CSM counterparts, as well as significantly greater average hip fracture-related LOS, per-patient charges, and per-patient payments (P < 0.001). Within this group of hip fractures with CSM, 441 patients (441/22,884; 1.9%) underwent cervical surgery prior to hip fracture, and 245 patients (245/22,884; 1.1%) underwent cervical surgery after hip fracture. These surgically treated patients with CSM were significantly younger but had higher incidence of medical comorbidities (P < 0.001) relative to hip fracture patients with CSM who did not receive cervical surgery at any point. Surgically treated CSM patients also had significantly lower per-patient charges and costs related to their hip fracture care relative to CSM patients with hip fracture who did not receive cervical surgery (P = 0.43, 0.84). This study describes for the first time a high prevalence of CSM in hip fracture patients on a populational level. The 1) prevalence of CSM among hip fracture patients and 2) incidence of hip fractures among CSM patients in this study far exceeded previous epidemiologic estimates. Hip fracture patients with CSM were seen to be significantly younger than hip fracture patients without CSM yet also were seen to have significantly more medical complexity. Hip fracture patients with CSM were also seen to have significantly greater per-patient costs and hip fracture related LOS, findings that are belied by low rates of surgical myelopathy treatment following hip fracture. This study describes for the first time a high prevalence of cervical myelopathy among hip fracture patients on a population level, with implications for both hip fracture prevention and cervical myelopathy diagnosis and treatment.