Calculate the Charlson Score in R

It is unlikely that anyone else will have data formatted in the same way as me, but it shouldn’t be too hard to convert this.

You just need a data where the rows represent patients, and there are a series of columns containing indicator variables for the components of the Charlson score[1].

The following function looks for these 20 variables, and uses a quick bit of matrix multiplication to generate the total score.

For reference, here is the table from the original paper containing the weights for the score.

Charlson Score

[1]: Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. Journal of Chronic Diseases. 1987;40:373-383.