The public domain modified ICD-10 classification as published in the public
domain by the US CDC. Currently this has a slightly different structure to
icd9cm_hierarchy
because the published data helpfully has a
leaf flag indicating whether a code is a billable leaf node, or
a code higher in the hierarchy which nevertheless will have a description.
There are annual revisions to this data. Currently, the 2016 edition is included.
Format: data frame, with columns for code, leaf status (0 or 1), short and long descriptions.