Using C-Reactive Protein Measurements to Predict Treatment Failure in Native Vertebral Osteomyelitis: A Multisite Retrospective Cohort Study Cohort Study.

Background: The management of native vertebral osteomyelitis (NVO) can be challenging due to imperfect prognostic tools to predict treatment outcome. It is common practice to use serial serum C-reactive protein (CRP) to help decide treatment response, although limited evidence supports this practice. We evaluated whether CRP assessment predicts treatment failure in NVO. Methods: We conducted a multisite retrospective cohort study at the University of Vermont Health Network among adults with NVO managed with ≥6 weeks of antibiotics and in whom there were ≥2 documented CRP values at least a week apart. The primary outcome was microbiologic or clinical failure of antibiotic therapy within 6 months of the initial diagnosis. Results: Among 628 patients identified by the initial screening criteria, 143 met inclusion criteria. In univariate analyses, the median last CRP value differed between patients with treatment success and those with treatment failure (8.9 vs 21.0 mg/dL; Conclusions: Serial CRP measurements were only weakly associated with treatment failure in NVO. This common clinical practice is likely of little value.