Leveraging hierarchy in medical codes for predictive modeling

ICD-9 codes are among the most important patient information recorded in electronic health records. They have been shown to be useful for predictive modeling of different adverse outcomes in patients, including diabetes and heart failure. An important characteristic of ICD-9 codes is the hierarchical relationships among different codes. Nevertheless, the most common feature representation used to incorporate ICD-9 codes in predictive models disregards the structural relationships.