Medical Risk and Comorbidity Tools for ICD-9-CM Data.

medicalrisk

medicalrisk is a collection of tools and data for performing patient-level medical risk adjustment using administrative data.

The data sets include icd9cm_charlson and icd9cm_elixhauser, which are data frames that map ICD-9-CM codes to comorbidities, using the Charlson and Elixhauser classifications respectively. The mapping comes from the paper by Quan in 2005, and uses the CMS ICD-9-CM table.
With a properly formatted source data frame of patients and ICD-9-CM values, the cast or dcast methods can be used to generate comorbidity tables.

The add_charlson_index_df method will calculate the Charlson Comorbidity Index for each patient.

For data sources that present ICD-9-CM codes as a comma-separated listing, the melt_icd9list method will convert such data tables into a one-row-per-code format suitable for join or merge to the icd9cm_* tables.

Data Sources

For implementation, testing, and examples several external data sources are used:

• ICD-9-CM code list from CMS
• Vermont Uniform Hospital Discharge Data Set
• Risk Stratification Index.