Table 1 Diagnosis cluster definitions for ICD-9 and ICD-10-CA
Diagnosis cluster | ICD-10-CA (5-character code) | ICD-9 (3-digit code) |
|---|---|---|
Ischemic stroke | I63.X (except I63.6, venous thrombosis), I64 (stroke not specified as hemorrhage or infarction), I66.0–2,4,8–9 (cerebral arterial stenosis or occlusion without infarction; included even though these codes specifically exclude infarction) | 434 (some codes exclude infarction, but these are rarely used in BC), 436 (acute cerebrovascular disease), 438 (late effects of cerebrovascular disease) |
TIA | G45.X (except G45.3, amaurosis fugax) | 435 |
Retinal | G45.3, H34.X (retinal vascular occlusion), H35.82 (retinal ischemia), H53.1 (transient visual loss) | 362 (retinal disorders), 368 (visual disturbances) |
Cerebral | G81.0 & G81.9 (hemiparesis), H53.4 & H53.9 (visual non-retinal), R29.5 (transient paralysis of limb), R29.8 (other neurological symptoms), R47.0, R47.1 & R7.8 (aphasia & dysarthria) | 781 (neurological symptoms), 341 (demyelinating symptom, but frequently used in our sample). Omit 784 (embeds speech in context of ‘head and neck’) |
Stenosis (asymptomatic) | I65.2, I65.3, I65.9 (stenosis of carotid or multiple arteries) | 433 (some codes include infarction, but these are rarely used in BC) |