Discordance between ICD-Coded Myocardial Infarction and Diagnosis according to the Universal Definition of Myocardial Infarction.
BACKGROUND
International Classification of Diseases (ICD) coding is the standard diagnostic tool for healthcare management. At present, type 2 myocardial infarction (T2MI) classification by the Universal Definition of Myocardial Infarction (MI) remains ignored in the ICD system. We determined the concordance for the diagnosis of MI using ICD-9 coding vs the Universal Definition.


METHODS
Cardiac troponin I (cTnI) was measured by both contemporary (cTnI) and high-sensitivity (hs-cTnI) assays in 1927 consecutive emergency department (ED) patients [Use of TROPonin In Acute coronary syndromes (UTROPIA) cohort] who had cTnI ordered on clinical indication. All patients were adjudicated using both contemporary and hs-cTnI assays. The Kappa index and McNemar test were used to assess concordance between ICD-9 code 410 and type 1 MI (T1MI) and type 2 MI (T2MI).


RESULTS
Among the 249 adjudicated MIs using the contemporary cTnI, only 69 (28%) were ICD-coded MIs. Of 180 patients not ICD coded as MI, 34 (19%) were T1MI and 146 (81%) were T2MI. For the ICD-coded MIs, 79% were T1MI and 21% were T2MI. A fair Kappa index, 0.386, and a McNemar difference of 0.0892 (P < 0.001) were found. Among the 207 adjudicated MIs using the hs-cTnI assay, 67 (32%) were ICD coded as MI. Of the 140 patients not ICD coded as MI, 27 (19%) were T1MI and 113 (81%) were T2MI. For the ICD-coded MIs, 85% were T1MI and 15% T2MI. A moderate Kappa index, 0.439, and a McNemar difference of 0.0674 (P < 0.001) were found.


CONCLUSIONS
ICD-9-coded MIs captured only a small proportion of adjudicated MIs, primarily from not coding T2MI. Our findings emphasize the need for an ICD code for T2MI.
Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Jorge
J
Díaz-Garzón
Division of Cardiology, Hennepin County Medical Center, Minneapolis, MN.|Minneapolis Heart Institute, Abbott Northwestern Hospital, Minneapolis, MN.
Yader
Y
Sandoval
Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Stephen W
SW
Smith
Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Sara
S
Love
Minneapolis Medical Research Foundation, Minneapolis, MN.
Karen
K
Schulz
Division of Cardiology, Hennepin County Medical Center, Minneapolis, MN.|Minneapolis Heart Institute, Abbott Northwestern Hospital, Minneapolis, MN.
Sarah E
SE
Thordsen
Division of Cardiology, Hennepin County Medical Center, Minneapolis, MN.|Minneapolis Heart Institute, Abbott Northwestern Hospital, Minneapolis, MN.
Benjamin K
BK
Johnson
Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Brian
B
Driver
Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Katherine
K
Jacoby
Division of Cardiology, Hennepin County Medical Center, Minneapolis, MN.|Minneapolis Heart Institute, Abbott Northwestern Hospital, Minneapolis, MN.
Michelle D
MD
Carlson
Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Kenneth W
KW
Dodd
Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Johanna
J
Moore
Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.|Department of Medicine, Hennepin County Medical Center, Minneapolis, MN.
Nathaniel L
NL
Scott
Department of Emergency Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
Charles A
CA
Bruen
Minneapolis Medical Research Foundation, Minneapolis, MN.
Ryan
R
Hatch
Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN; apple004@umn.edu.|Minneapolis Medical Research Foundation, Minneapolis, MN.
Fred S
FS
Apple
D006801:Humans; D038801:International Classification of Diseases / Q000706:statistics & numerical data*; D009203:Myocardial Infarction / Q000175:diagnosis*; D019210:Troponin I / Q000032:analysis
D019210:Troponin I