Add the external cause flag (E) to appropriate ICD-9 UCOD codes

All UCOD ICD-9 codes between 800 and 999 are external cause of injury (E) codes. Because this operates on the padded 4-character code (e.g. "8001" for 800.1, as produced by pad_3char_codes(), which clean_icd9_data() already runs before this), the numeric guard checks 8000-9999, the padded-code equivalent of the 800-999 range. We append the E to them to make regexing across UCOD and record columns consistent.

Usage

prefix_e_to_ucod(icd9_ucod)

Arguments

icd9_ucod

The ucod column from an ICD-9 dataframe

Value

vector

Examples

prefix_e_to_ucod(c(7951, 8001, 9992, 6000, 4000))
#> [1] "7951"  "E8001" "E9992" "6000"  "4000"