ICD 10 Codes dataset: Please help

[Helen Oni]

Hi there,

Please I urgently need help with generate new variable consisting ICD 10 codes related to substance use from existing ICD 10 codes variable.
To be specific, I am working on a dataset that consist numerous ICD 10 codes as observations, however, I am only interested in ICD 10 codes related to substance use (alcohol and illicit drug use). Of note, I have a list of all the codes I am interested in.
Hence, I will like to extract all the ICD 10 codes related to substance use under a new variable.
Please can someone guide me as to how to go about this!!!

[Rich Goldstein]

your set up is not completely clear to me but here is a guess: make a new data set of just the substance use codes and then merge the two dates; _merge=3 is then what you want; see

help merge

[Shannon Campbell]

I can help with that.

Let's say your ICD codes are in a variable called icd10.

Substance use is the F10 to F19 range in ICD.

So what I would do:

gen new_icd10=icd10 if strmatch(icd10, "F1*")

A string match looks for where a variable contains certain characters; the asterisk shows where anything can come before or after. So what this does is create a new variable, new_icd10, that copies the value from your original variable if they start with the characters F1, no matter what comes after that. If it doesn't start with F1, it will be a blank value.

You would end up with something like this:

icd10	new_icd10
F10.151	F10.151
F20.2	-
F13.92	F13.92
J01.0	-
G09	-
F11.10	F11.10

Just a note: depending on what you're working on, you may want to exclude nicotine from your analysis. Nicotine is the F17 range.

[Marcos Almeida]

In Stata, you have - icd10 - command for that matter. This is a very handy approach when dealing with ICD 10 codes.

[Helen Oni]

Thank you so much Shannon, I think this is what I need. I will try it now and let you know if it works.

[Helen Oni]

I can help with that.

Let's say your ICD codes are in a variable called icd10.

Substance use is the F10 to F19 range in ICD.

So what I would do:

gen new_icd10=icd10 if strmatch(icd10, "F1*")

A string match looks for where a variable contains certain characters; the asterisk shows where anything can come before or after. So what this does is create a new variable, new_icd10, that copies the value from your original variable if they start with the characters F1, no matter what comes after that. If it doesn't start with F1, it will be a blank value.

You would end up with something like this:

icd10	new_icd10
F10.151	F10.151
F20.2	-
F13.92	F13.92
J01.0	-
G09	-
F11.10	F11.10

Just a note: depending on what you're working on, you may want to exclude nicotine from your analysis. Nicotine is the F17 range.

Hi Shannon, thanks much, the syntax works.

[Helen Oni]

Hi Shannon, thanks much, the syntax works.

Hi Shannon, I'm having trouble extracting more that one code at a time. For instant, I want to generate new variable that consist of the ICD10 F and ICD10 let say G at the same time.
something like this: gen new_icd10p123=diagnosis_codep if strmatch(diagnosis_codep, "F1*" "G3*" "G6*") but this didn't work.

Please help.

[Shannon Campbell]

Hi, Helen -

I saw your private message, but it seems I can't reply to you directly. Hope you see this.

If you want it to be more than one string match at a time, you put a | between each clause. That basically means "or" in this context; if it matches this or this, do this.

gen new_icd10p123=diagnosis_codep if strmatch(diagnosis_codep, "F1*") | strmatch(diagnosis_codep, "G3*") | strmatch(diagnosis_codep, "G6*")

The only problem is that there is a limit - I think you can't do more than 8 clauses at a time. So if you have more than 8 codes, you'd probably want to switch to doing a replace after the first line.

You do your gen new, and then...

replace new_icd10p123=diagnosis_codep if strmatch(diagnosis_codep, "F2*") | strmatch(diagnosis_codep, "F3*") [etc.]