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Central Distributor SEDD: Description of Data Elements

 
DXn - ICD-9-CM Diagnosis
 
Documentation Sections:
General Notes
Uniform Values
State Specific Notes
General Notes
 

In data prior to the fourth quarter of 2015, diagnoses reported on HCUP records are based on the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and stored in the data elements DXn. Beginning in the fourth quarter of 2015, diagnoses reported on HCUP records are based on the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) and stored in the data elements I10_DXn.

In the HCUP inpatient databases, the first listed diagnosis is the principal diagnosis defined as the condition established after study to be chiefly responsible for occasioning the admission of the patient to the hospital for care. In the HCUP outpatient databases, the first listed diagnosis is the condition, symptom, or problem identified in the medical record to be chiefly responsible for the outpatient visit.

In the HCUP databases, ICD-9-CM diagnoses are represented as 3- to 5-character alphanumeric codes with implicit decimals (i.e., decimals not included). Prior to data year 2014, the HCUP data elements for ICD-9-CM diagnoses are length 5; in 2014, they are length 7 in the HCUP State Databases. . The first digit may be numeric or character (characters E or V only) with all subsequent digits being numeric. The codes are left-justified in the HCUP databases so that prior to 2014 there are two spaces following a 3-character diagnosis code and one space following a 4-character diagnosis code (four and three spaces, respectively, in 2014). For example, the diagnosis code 863.0 would appear as '8630 ' with trailing blanks in HCUP data. Any zeroes at the beginning of the code are significant; they are part of the code. For example, the ICD-9-CM diagnosis code 086.3 would be stored in the HCUP databases as '0863 ' and the diagnosis 008.63 would be stored as '00863'.

The original value of the first listed diagnosis (DX1), whether blank or coded, is retained in the first position of the diagnosis vector. Starting at the first secondary diagnosis (DX2), the diagnoses are shifted during HCUP processing to eliminate blank secondary diagnoses. For example, if DX2 and DX4 contain nonmissing diagnoses and DX3 is blank, then the value of DX4 is shifted into DX3. Secondary diagnoses are never shifted into the first listed position (DX1).

Prior to 2003, external cause of injury codes (E codes) are included in the diagnosis array (DXn). Beginning in 2003, any separately reported E codes and any E codes found in the diagnosis array are retained in a separate array specific to E codes (ECODEn).

Diagnoses are compared to a list of ICD-9-CM codes valid for the discharge date. Anticipation of or lags in response to official ICD-9-CM coding changes are permitted for discharges occurring within a window of time around the official ICD-9-CM coding changes (usually October 1). In the data prior to 1998, a six months window (three months before and three months after) is allowed. Beginning in the 1998 data, a year window (six months before and six months after) is allowed. If the diagnosis contains intermittent blank characters or is zero filled, then the diagnosis will be considered invalid.

Diagnoses are compared to the sex of the patient (edit check EDX03 beginning in the 1998 data and ED1nn prior to 1998) and the patient's age (edit checks EAGE04 and EAGE05 beginning in the 1998 data and ED3nn and ED4nn prior to 1998) for checking the internal consistency of the record.

How invalid and inconsistent codes are handled varies by data year.

  • Beginning in the 1998 data, invalid and inconsistent diagnoses are masked directly. Validity flags are not included on the HCUP record. Clinical Classifications Software (CCS) data elements are coded with respect to the diagnosis.
Invalid Diagnosis Inconsistent Code
The value of DXn "invl" "incn"
DXCCSn Set to invalid (.A). Set to inconsistent (.C)
  • Prior to 1998 data, invalid and inconsistent diagnoses are retained on the record. Validity flags (DXVn) indicate invalid, inconsistent diagnosis codes. Clinical Classifications Software (CCS) data elements use the former name (DCCHPRn). The CCS was formerly known as the Clinical Classifications for Health Policy Research (CCHPR). The diagnosis related data elements are coded as follows:
Invalid Diagnosis Inconsistent Code
The value of DXn Unchanged Unchanged
DXVn Set to 1 Set to inconsistent (.C)
DCCHPRn Set to invalid (.A) Retained (values 1-260)

The validity flags (DXVn) need to be used in connection with any analysis of the diagnoses (DXn).

The maximum number of diagnoses reported varies by state. HCUP retains all diagnosis fields provided by the data source.

 
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Uniform Values
 
VariableDescriptionValueValue Description
DXnICD-9-CM DiagnosisannnnDiagnosis code
BlankMissing
invlInvalid: beginning with 1998 data, EDX02
incnInconsistent: beginning with 1998 data, EAGE04, EAGE05, EDX03
 
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State Specific Notes

Arizona

Beginning in 2008, Arizona reports six "cause of injury" E-codes in separate fields. Prior to 2008, Arizona reports five "cause of injury" E-codes.

Arizona reports five "cause of injury" E-codes in separate variables. During processing these separately reported E-codes, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn).



Georgia

In 2002, the percentage of injury records with an external cause of injury (E code) is lower than following years. The data source explained that the outside data vendor that prepared the 2002 data file may have removed certain E codes. In 2003, the data processing was brought in-house. At that time, the data source provided training across the state to educate the Georgia hospitals on new data submission requirements. Part of that education included an emphasis on reporting E codes on injuries.



Hawaii

Hawaii reports one "cause of injury" E code as a separate data element. Prior to 2003, During HCUP processing, this E code was placed after the last non-missing diagnosis code during HCUP processing. Beginning with 2003 HCUP processing, this E code is placed at the beginning of the separate HCUP E-code array (ECODEn).



Iowa

Beginning in data year 2001, the Iowa Hospital Association prohibits the release of two types of discharges:

  • HIV Infections (defined by MDC of 25) and
  • Behavioral Health including chemical dependency care or psychiatric care (defined by a service code of BHV).

These discharges were not included in the source file provided to HCUP and are therefore not included in the HCUP files.

Beginning in 1994, Iowa reports one "cause of injury" E-code. Beginning in 1998, Iowa added one "place of injury" E-code. During processing of the 1994 to 2002 data, these separately reported E-code variables are placed at the end of the diagnosis vector; since the vector is packed during processing to remove blanks, the position of the E-code for a specific discharge depends on the number of diagnoses reported. Beginning in 2003, the two separately reported E-codes, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn).



Kansas

Kansas supplied 30 diagnoses to HCUP although any given discharge reports only 25 diagnoses.



Kentucky

Prior to 2002, Kentucky reports one "cause of injury" E-codes as a separate variable. Beginning in June 2002, Kentucky reports two separate E-code fields. Prior to 2003, during HCUP processing, these separately reported E-codes were placed after the last non-missing secondary diagnosis. Beginning in 2003, the two separately reported E-codes, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn). Beginning 2008, a third E-code was provided and placed into the E-cdoe arrays.


Kentucky supplied diagnosis codes in a field length of 7. Only the first five characters contained in the left-justified source field were used to assign the HCUP diagnosis codes.



Maine

Maine reports one "cause of injury" E-code in a separate variable. Prior to 2003, during HCUP processing, this E-code was placed after the last non-missing diagnosis code. Beginning in 2003, the separately reported E-code, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn).



Maryland

Maryland reports one "cause of injury" E-code as a separate variable. Prior to 2003, during HCUP processing, this separately reported E-code was placed after the last non-missing secondary diagnosis. Beginning in 2003, the separately reported E-code, and any E-codes encountered in the diagnosis variables are placed in a separate array specific to E codes (ECODEn).

Maryland supplied diagnosis codes in a field of length 7. Only the first five characters contained in the left-justified source field were used to assign the HCUP diagnosis codes.



Massachusetts

Beginning in 1993, Massachusetts reported one "cause of injury" E-code. Prior to 2003, during HCUP processing, the separately reported E-code was placed after the last non-missing secondary diagnosis. E-codes can appear in other secondary diagnosis codes. Beginning in 2003, the separately reported E-code, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn).



Minnesota

Minnesota reports one "cause of injury" E-codes in a separate variable. Prior to 2003, during HCUP processing, this E-code was placed after the last non-missing diagnosis code. Beginning in 2003, the separately reported E-codes, and any E-code encountered in the diagnosis variables are placed in a separate array specific to E codes (ECODEn).



Nebraska

The Nebraska Hospital Association prohibits the release of discharge records for patients with HIV diagnoses. These discharges were not included in the source file provided to HCUP and are therefore not included in the HCUP files.


Nebraska reports one "cause of injury" E-code in a separate variable. Prior to 2003, during HCUP processing, this E-code was placed after the last non-missing diagnosis code. Beginning in 2003, the separately reported E-code, and any E-code encountered in the diagnosis variables are placed in a separate array specific to E codes (ECODEn).



New Jersey

New Jersey reports one "cause of injury" E-codes as a separate variable. The separately reported E-code, and any E-codes encountered in the diagnosis variables are placed in a separate array specific to E codes (ECODEn).



New York

Beginning in 2008, New York suppressed the identifier for the hospital (DSHOSPID) on records with an indication of induced abortion. These records are retained in the HCUP files with the DSHOSPID set to "BLNK". New York identifies an indication of induced abortion by ICD-9-CM diagnosis or procedure code:

  • An admitting, principal, or secondary diagnosis of "6350" through "6399", or "7796".
  • A principal or secondary procedure of "690", "695", "696", "6993", "738", "7491", "750", or "9649".


North Carolina

North Carolina supplied diagnosis codes in a field length of 6. Only the first five characters contained in the left-justified source field were used to assign the HCUP diagnosis codes.



South Carolina

Prior to 2000 data, a small number of discharges explicitly included decimals in the diagnosis field, usually the decimal is implicit. This is problematic because South Carolina supplied diagnoses in a field of length 5. If decimals were included, then a valid 5-digit code would be truncated. For example, the diagnosis for unspecified sickle cell anemia "28260" would be incorrectly reported as "262.6". Prior to 1998, invalid diagnosis codes are marked by a validity flag (DXVn = 1). Beginning in 1998, invalid diagnosis codes are masked (Dxn = "invl").


Beginning in 2000 data this was no longer a problem; explicit decimals were not included in the diagnosis codes.



South Carolina

E-codes

Prior to data year 2000, one cause of injury E-code and one place of injury E-code may be missing from South Carolina discharges even though E-codes are present in the secondary diagnosis fields. Separate E-code fields that are collected by the data organization in South Carolina were not obtained for HCUP. Beginning in 2000, these separate E-code fields were obtained by HCUP. Beginning in 2003, the separately reported E-codes, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn).


South Carolina does not require the reporting of E-codes in the range E870-E876 (misadventures and abnormal reactions). Beginning with the 2003 Intramural databases, these E-codes were removed from the HCUP data, however they may be present on earlier years of HCUP data. AHRQ researchers and project staff may not include these diagnosis codes in any analyses (effective May 2004).



Utah

Utah reports one "cause of injury" E-code as a separate variable. Prior to 2003, during HCUP processing, this E-code was placed after the last non-missing diagnosis code. Beginning in 2003, the separately reported E-code, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn).



Vermont

Vermont reports one "cause of injury" E-code as a separate variable. Prior to 2003, during HCUP processing, this separately reported E-code was placed after the last non-missing secondary diagnosis. Beginning in 2003, the separately reported E-code and any E-codes encountered in the diagnosis variables are placed in a separate array specific to E codes (ECODEn).

Vermont supplied diagnosis codes in a field of length 6. Only the first five characters contained in the left-justified source field were used to assign the HCUP diagnosis codes.



Wisconsin

To comply with statutory requirements, Wisconsin modified diagnosis and procedure codes that explicitly referenced induced termination of pregnancy to eliminate distinctions between induced and spontaneous termination. The following codes were modified:

  • Diagnoses with the first three digit of 634, 635, 636, 637, 638 were recoded to 637, while retaining the reported fourth digit,
  • Procedure 6901 was changed to 6902,
  • Procedure 6951 was changed to 6952,
  • Procedure 6993 was changed to 6999,
  • Procedure 7491 was changed to 7499,
  • Procedure 750 was changed to 7599, and
  • Procedures 9641-9649 were changed to 964 (which would be flagged as invalid, PRV=1).

Beginning Q4 2015, the following codes were modified:

  • Diagnosis Z33.2 was changed to Z31.9,
  • Diagnoses O04x and O07x were changed to O03.9,
  • Procedure 10A07ZZ was changed to 10D17ZZ,
  • Procedure 10A08ZZ was changed to 10D18ZZ,
  • Procedure 10A07ZZ was changed to 10D17ZZ,
  • Procedure 10A08ZZ was changed to 10D18ZZ,
  • Procedure 10A07ZW was changed to 0UCB7ZZ,
  • Procedure 10A00ZZ was changed to 10D00Z0,
  • Procedure 10A03ZZ was changed to 0UC93ZZ,
  • Procedure 10A04ZZ was changed to 0UC94ZZ,
  • Procedure 10A07ZX was changed to 3E0P7GC.

Wisconsin reports one "cause of injury" E-code. Prior to 2003, during HCUP processing, this separately reported E-code was placed after the last non-missing secondary diagnosis. Beginning in 2003, the separately reported E-code, and any E-codes encountered in the diagnosis variables, are placed in a separate array specific to E codes (ECODEn).


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Internet Citation: HCUP Central Distributor SEDD Description of Data Elements - All States. Healthcare Cost and Utilization Project (HCUP). September 2008. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/db/vars/sedddistnote.jsp?var=dxn.
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Last modified 9/11/08