icd9cm_sessler_rsi {medicalrisk}

Returns composite Sessler risk stratification index, given a list of ICD-9-CM codes.

Description

ICD-9-CM codes must have periods removed. Diagnostic codes are prefixed with 'D' while procedure codes are prefixed with 'P'. So, diagnostic code 404.03 should be "D40403".

Usage

icd9cm_sessler_rsi(icd9)

Arguments

icd9

a unique character vector of ICD-9-CM codes

Details

Note: A subsequent publication (Sigakis, 2013) found the following: "Calibration "in-the-large" for RSI in-hospitalmortality illustrated a discrepancy between actual (1.5 identified a regression constant (-2.198) in the published RSI "all-covariates.xls" file that was not used in the published SPSS implementation macro."

Value

The risk stratification index score

Author(s)

Tom Joseph <[e-mail]>, Patrick McCormick <[e-mail]>

References

1. Sessler DI, Sigl JC, Manberg PJ, Kelley SD, Schubert A, Chamoun NG. Broadly applicable risk stratification system for predicting duration of hospitalization and mortality. Anesthesiology. 2010 Nov;113(5):1026-37. doi: 10.1097/ALN.0b013e3181f79a8d.

2. Sigakis MJG, Bittner EA, Wanderer JP: Validation of a risk stratification index and risk quantification index for predicting patient outcomes: in-hospital mortality, 30-day mortality, 1-year mortality, and length-of-stay. Anesthesiology 2013; 119:525-40

Examples

# Calculate RSI for each patient ("id") in dataframe
cases <- data.frame(id=c(1,1,1,2,2,2),
  icd9cm=c("D20206","D24220","D4439","D5064","DE8788","D40403"),
  stringsAsFactors=TRUE)
library(plyr)
ddply(cases, .(id), function(x) { icd9cm_sessler_rsi(x$icd9cm) } )