Sample selection and characteristics of the Clinical Modification of the 9th Revision of the International Classification of Diseases (ICD-9-CM)/Clinical Modification of the 10th Revision of ICD (ICD-10-CM) dually coded datasets
| Characteristics | MCA | MCB | |||
| ICD-9-CM | ICD-10-CM | ICD-9-CM | ICD-10-CM | ||
| Input | Number of unique records | N=5167 | N=5305 | ||
| Step 1 | Number of inpatient records with at least one valid ICD-9-CM and ICD-10-CM diagnosis code | n=4832 | n=5211 | ||
| Number of DX and external cause codes per record: min, max | 1 to 48 | 1 to 62 | 1 to 91 | 1 to 94 | |
| Number of external cause codes per record: min, max | 0 to 6 | 0 to 5 | 0 to 8 | 0 to 5 | |
| Number of unique DX and external cause codes | 3845 | 5310 | 4269 | 6150 | |
| Mean number of DX and external cause codes per record | 8.9 (SD=6.5) | 8.4 (SD=6.0) | 12.5 (SD=8.1) | 12.3 (SD=7.9) | |
| Number of unique external cause codes | 277 | 355 | 281 | 323 | |
| Average number of external cause codes per record for records with at least one external cause code | 2.2 (SD=0.9) | 2.2 (SD=1.1) | 1.3 (SD=0.6) | 1.3 (SD=0.8) | |
| Step 2 | Number of records with a principal diagnosis of injury (see surveillance definitions, table 1) | n=657 | n=659 | n=537 | n=544 |
| Step 3 | Number of records with at least one valid external cause code from external cause of injury matrices | n=657 | n=632 | n=532 | n=526 |
| Completeness of external cause coding* | 100% | 95% | 99% | 97% | |
| Number of records that have at least one valid ICD-9-CM and one valid ICD-10-CM external cause code | n=632 | n=520 | |||
*Number of records with at least one valid external cause of injury code/number of records where principal diagnosis is an injury code.