SPECIFICITY OF ICD-9-CM CODING PRACTICES FOR STROKE REHABILITATION

Designed for acute care classification, the 9th version of the International Classification of Disease, Clinical Modification (ICD-9-CM) is also used to describe the principal diagnosis in medical rehabilitation. ICD-9-CM (ICD-9) coding practices for all stroke cases found in two nationally representative databases were examined (sample sizes over 17,000 and over 2,000). Of the more than 100 codes selected, four were indicated for 67% and 72% of stroke cases in the two data sets, respectively. Codes 436 and 438 distinguish acute from late stroke effects; whereas code 434.9 identifies stroke, but not its duration. The most frequently used code in the larger database, 342.9, refers to the manifestation of hemiplegia rather than to diagnosis, and thus is not specific to stroke. Other less frequently selected ICD-9 codes are more specific to the underlying pathophysiology (e.g., thrombosis, embolus or hemorrhage). Results emphasize the need for more precise selection of etiologic ICD-9 codes for stroke rehabilitation so that they describe specific pathology.