lookupComorbidities

contains the data with at least one field named by <code>visitId</code>,
and likely a field "poa" for the present on arrival flag. Additional fields
are preserved. Merging fields with duplicated visitId will behave according
to default of <code>mergeFun</</code>

is one of the pre-prepared lookup tables. e.g.
'comorbidAllInpt','comorbidPoaInpt','comorbidNotPoaInpt' If a character
string is given (vector of unit length), then the name is used to lookup
the data in current environment tree. If a data frame is given,

icd9lk

The name of the column in the data frame which contains the
patient or visit identifier. Typically this is the visit identifier, since
patients come leave and enter hospital with different ICD-9 codes. It is a
character vector of length one. Defaults to "

visitId

is the function used to merge the comorbidity data with the
visitId list, using visitId as the key. Can be left as default <code>merge</code>
but this has limited ability when identical fields appear, and in how field
name clashes can rename; neither does

mergeFun

additional arguments passed to <code>mergeFun</code>

merges the data frame <code>dat</code> with pre-calculated icd9
  comorbidities by <code>visitId</code>

internal

This package allows accurate manipulation, validation and
    comparison of ICD-9-CM (clinical modification) codes. Although ICD-9 codes
    appear numeric, this is not the case, since trailing zeroes, and a mixture
    of decimal and non-decimal "short" format codes exist. Tools to map ICD-9
    codes to co-morbidities are also provided, with mappings from Quan (Deyo
    and Elixhauser versions), Elixhauser and AHRQ included.

lookupComorbidities: lookup pre-calculated co-morbidities for given list of visit IDs

Description

Usage

Arguments

`Value`