Fig. 2

Adjusted mean initial procedure and follow-up hospital charges (95% CIs) were significantly lower with V-CBA versus rhBMP-2. **P < 0.0001. Multivariate regression models were adjusted with the following confounding factors as covariates: race, ethnicity, Charlson comorbidity index, health insurance status, initial admission type, initial admission source, initial discharge status, cage insertion, multiple levels treated, hospital size, hospital teaching status, hospital population served, and hospital region. Data for patients re-admitted during the 12-month follow-up period did not include those who may have received follow-up treatment outside of the Premier Healthcare System