Prognostic Factors for Failure of Antibiotic Treatment in Patients With Osteomyelitis of the Spine.

STUDY DESIGN: Retrospective cohort study.

OBJECTIVE: The aim of this study was to identify factors independently associated with antibiotic treatment failure in patients with spinal osteomyelitis.

SUMMARY OF BACKGROUND DATA: There are few studies that have identified risk factors for antibiotic treatment failure in medically managed spinal osteomyelitis. Identifying such factors could help to identify patients who can be treated solely with antibiotics.

METHODS: All patients who underwent antibiotic treatment for spinal osteomyelitis in one of our institutions between January 1, 2001 and January 1, 2015 were identified. Patients who underwent surgery before the start of the antibiotic treatment were excluded.

RESULTS: We included 215 patients with a mean age of 58 years; 63 (29%) patients had failure of antibiotic treatment. Diabetes (hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.03-2.79, P = 0.037), fever (HR 1.61, 95% CI 0.93-2.79, P = 0.088), osteomyelitis at an additional site (HR 5.17, 95% CI 2.63-27.9, P = 0.001), and the presence of an epidural abscess (HR 1.91, 95% CI 1.05-3.45, P = 0.033) were associated with failure of antibiotic treatment. In the multivariate Cox regression analysis, diabetes (HR 1.69, 95% CI 1.03-2.79, P = 0.019), osteomyelitis at an additional site (HR 8.26, 95% CI 2.51-27.2, P = 0.001), fever (HR 1.77, 95% CI 1.00-3.12, P = 0.050), and the presence of an epidural abscess (HR 1.82, 95% CI 1.06-3.13, P = 0.030) were independently associated with failure of antibiotic treatment.

CONCLUSION: Antibiotic treatment failed in 29% of patients; diabetes, current other osteomyelitis, and having an epidural abscess were independently associated with failure of antibiotic treatment.

LEVEL OF EVIDENCE: 3.