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; P < .01), as did the median percent decrease from first to last CRP measurement (88.9% vs 76.9% reduction; P = .03). However, in multivariate analyses adjusting for Staphylococcus aureus infection and epidural abscess we observed only weak and nonsignificant associations between CRP values and treatment failure (odds ratios, 1.02 for median last CRP value [P = .06] and 0.99 for median percent difference (P = .11).

CONCLUSIONS

Serial CRP measurements were only weakly associated with treatment failure in NVO. This common clinical practice is likely of little value.