Glassman S, et al. – The present study was undertaken to determine whether predictors of hospital readmission and surgical site infection (SSI) after lumbar fusion would be the same in United States, Denmark, and Japan. Researchers realized differences in predictors of SSI and hospital readmission in the United States, Denmark, and Japan, suggesting that risk stratification models should be population specific or adjusted. Some differences in measured parameters exist in the three databases analyzed; however, patient and procedure selection also appeared to differ and could limit the ability to directly pool data from different regions. Therefore, risk stratification models developed in one country could not be directly applicable to other countries.