title: The use of comparability ratios to adjust hospital trend data.
abstract: Hospital trend data may be affected by changes in diagnostic coding schemes. We studied the change from ICDA-8 (I-8) to ICD-9-CM (I-9) in a sample of roughly 13,600 double-coded Veterans Administration hospital diagnoses. Comparability ratios were computed and used to adjust trend data which overlap the time period when the shift from I-8 to I-9 occurred. With this adjustment for change in diagnostic coding scheme, apparent diagnostic trends are substantially altered.
mesh_terms: D003933:Diagnosis; D004194:Disease / Q000145:classification; D006760:Hospitalization; D006787:Hospitals, Veterans; D006801:Humans; D009017:Morbidity; D013223:Statistics as Topic; D014481:United States