Clinical Manifestations, Long-Term Trends, and Risk Factors for Treatment Failure in Native Vertebral Osteomyelitis: A 26-Year Mayo Clinic Experience

BACKGROUND: Native vertebral osteomyelitis (NVO) is a life-threatening spinal infection with rising incidence and significant morbidity. Despite its growing burden, long-term data on clinical characteristics, management trends, and outcomes remain limited. METHODS: We conducted a 26-year multicenter retrospective cohort study of adults (≥18 years) diagnosed with NVO at Mayo Clinic sites between 1999-2024. Demographic, microbiologic, treatment, and outcome data were analyzed across five time periods. Predictors of treatment failure were assessed using a multivariable competing risk model. RESULTS: Among 1,255 patients (median age 67; 66% male), lumbosacral involvement was most common (65%), and 21% had multilevel involvement. Pathogens were identified in 77%, most commonly S. aureus (49%; MSSA 37%, MRSA 13%). Over time from 1999-2004 to 2020-2024, Gram-negative bacilli increased from 6% to 14% (p=0.048).Comorbidities including chronic kidney disease (10% to 21%), active chemotherapy (6% to 11%), and immunosuppression (8% to 17%) increased significantly. Additionally, 1-year treatment failure declined (16% to 10%). In multivariable analysis, diabetes mellitus (sHR 1.92, 95% CI 1.18-3.13) and multilevel involvement (sHR 1.67, 95% CI 1.17-2.38) were associated with increased incidence of treatment failure, while concurrent infections (sHR 0.57, 95% CI 0.37-0.87) and higher Charlson Comorbidity Index (CCI) (sHR 0.62, 95% CI 0.43-0.90) were associated with lower failure. CONCLUSION: This large multicenter cohort highlights increasing host complexity, shifting microbiology, and predictors of failure, emphasizing the importance of early risk stratification and tailored strategies, such as multidisciplinary evaluation and close follow-up of high-risk patients to improve outcomes.