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ICD9CODE
ICD-9-CM code for condition

Description

For all current conditions, ICD9CODE reports the ICD-9-CM diagnosis code for the condition. To preserve confidentiality, AHRQ offers a version of the ICD-9-CM codes where the fully specified ICD-9-CM codes have been collapsed to 3-digit code categories. For procedure codes, see ICD9PROC. Beginning in 2016, conditions are coded to ICD-10-CM codes (ICD10CODE), and not ICD-9-CM codes.

IPUMS MEPS reports the universe for each variable based on a thorough review of the original MEPS documentation. Investigating the data may reveal cases that do not meet the stated universe. Users are encouraged to validate universes for their analyses.

ICD-9-CM data collection and editing 

To determine the fully specified ICD-9-CM code, interviewers recorded the medical condition reported by the respondent as verbatim text, which was then coded by professional coders. AHRQ provides the following caveat for using ICD9CODE, "Although codes were verified and error rates did not exceed 2.5 percent, analysts should not presume this level of precision in the data; the ability of household respondents to report condition data that can be coded accurately should not be assumed."

Conditions are initially coded "9999" (Unknown) for three reasons: 1) the text indicated that the condition was unknown; 2) the text indicated the condition could not be diagnosed by a doctor; or 3) the specified condition was not codeable and a procedure could not be discerned from the text. When the verbatim text strictly denoted a procedure and not a condition, ICD9CODE was coded to "9996" (NIU).

To preserve confidentiality, the fully specified ICD-9-CM codes have been collapsed to 3-digit code categories and some codes are recoded to broader categories for conditions that occur fewer than 20 times within a year's conditions file and for clinically rare conditions. For pregnancy conditions for a person younger than 16 or older than 44, ICD9CODE was recoded to "9999" (due to the design of the survey most deliveries are coded as pregnancies). In some additional cases, ICD9CODE has been recoded to "9999" for confidentiality reasons.

 

Prior to 2013, there are less than 1,000 conditions coded to "9999" in each year. From 2013-2015 there is a substantial increase in the number of conditions coded "9999", with at least 7,000 in each year. This increase appears to be the result of stricter confidentiality requirements, as there is no matching increase in CCCODE, which prior to 2013 had similar rates of missing cases.

ICD9CODEĀ is on the condition record (see RECTYPE for more details on the different record types in IPUMS MEPS). Variables offered on the condition record through IPUMS MEPS are derived from the Medical Conditions file provided by AHRQ. Please see our overview of the event, medical conditions, and prescribed medicines variables, including how those variables are offered through IPUMS MEPS, and general considerations to keep in mind when conducting analyses using these variables.

Codes

ICD9CODE is a 4-character string variable.

ICD-9-CM Codes

Comparability

The meaning of ICD9CODE is completely comparable over time. Changes in ICD-9-CM codes and criteria for recoding to "9999" (Unknown) due to confidentiality concerns may introduce some comparability issues.

Universe

  • 1996-2015: All current conditions.

Availability

  • 1996-2015

Weights

Flags

This variable has no flags.