Comparison of adult spinal deformity patients with and without rheumatoid arthritis undergoing primary non-cervical spinal fusion surgery: a nationwide analysis of 52,818 patients

Abstract

Background context: Numerous studies have analyzed the impact of rheumatoid arthritis (RA) on the cervical spine and its related surgical interventions. However, there is a paucity of literature available conducting the same analyses in patients with non-cervical spine involvement.

Purpose: The objective of this study was to compare patient characteristics, comorbidities, and complications in patients with and without RA undergoing primary non-cervical spinal fusions.

Study design/setting: This is a retrospective national database review.

Patient sample: A total of 52,818 patients with adult spinal deformity undergoing non-cervical spinal fusions (1,814 patients with RA and 51,004 patients without RA).

Outcome measures: The outcome measures in the study include patient characteristics, as well as complication and mortality rates.

Materials and methods: Using the Nationwide Inpatient Sample from 2003 to 2014, International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis and procedure codes were used to identify patients aged ≥18 years old with and without RA undergoing primary non-cervical spinal fusions. Univariate analysis was used to determine patient characteristics, comorbidities, and complication values for each group. Bivariate analysis was used to compare the two groups. Significance was set at p<.05.

Results: Patients with RA were older (p<.001), were more likely to be women (p<.001), had increased rates of osteoporosis (p<.001), had a greater percentage of their surgeries reimbursed by Medicare (p<.001), and more often had weekend admissions (p=.014). There was no difference in all the other characteristics. Patients with RA had higher rates of iron deficiency anemia, congestive heart failure, chronic pulmonary disease, depression, and fluid and electrolyte disorders (all, p<.001). Patients without RA had higher rates of alcohol abuse (p=.027). There was no difference in all the other complications. There was no difference in mortality rate (p=.99). Total complications were greater in patients with RA (p<.001). Patients with RA had higher rates of infection (p=.032), implant-related complications (p=.010), incidental durotomies (p=.001), and urinary tract infections (p<.001). No difference existed among the other complications.

Conclusions: Patients with RA have an increased number of comorbidities and complication rates compared with patients without RA. Such knowledge can help surgeons and patients with RA have beneficial preoperative discussions regarding outcomes.

Keywords: Complication rates; Nationwide inpatient sample; Non-cervical spinal fusion; Outcomes; RA; Rheumatoid arthritis; Scoliosis; Spinal deformity.