Table 1.
Codes for Outcomes and Comorbid Conditions Used in the Analysis
| Variable | ICD-9-CM Diagnosis Codes | Diagnosis Related Groups | Hierarchical Condition Categories |
|---|---|---|---|
| Outcome | |||
| Atrial fibrillation | 427.31 | ||
| Heart failure | 428.x, 402.x1, 404.x1, or 404.x3 |
||
| Stroke or transient ischemic attack | |||
| Subarachnoid hemorrhage | 430.x | ||
| Intracerebral hemorrhage | 431.x | ||
| Ischemic stroke | 433.x1, 434.x1, or 436 | ||
| Transient ischemic attack | 435.x | ||
| Readmission | |||
| Cardiovascular causes | 104–112, 115–118, 121–145, 479, 514–518, 525–527, 535, 536, and 547–558 (before October 1, 2007); 215–238, 242–254, 258–262, 280–316 (on or after October 1, 2007) |
||
| Covariates | |||
| Comorbid conditions | |||
| Protein-calorie malnutrition | 21 | ||
| Dementia | 49–50 | ||
| Disability | 100, 101, 102, 68, 69, 177, and 178 |
||
| Major psychiatric disorders | 54, 55, and 56 | ||
| Chronic liver disease | 25, 26, and 27 |
Abbreviation: ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification.