The effect of physician terminology preference on coronary heart disease mortality: an artifact uncovered by the 9th revision ICD.

We dual coded 2,268 deaths due to heart disease occurring in Maryland, using the 8th and 9th revisions of the International Classification of Diseases (ICDA-8, Adapted for Use in the United States, and ICD-9). Certifier preference was for generalized cardiovascular terms rather than terms specific to the heart, resulting in an artifactual change in chronic ischemic heart disease death (IHD) rates in Maryland between 1978 and 1979 because the 8th and 9th ICD revisions classified these terms differently. Medical examiners were more likely to use these generalized cardiovascular terms as were physicians who went to certain medical schools in the state. The physician's terminology preference was associated with the sex and race of the decedent and was related to aspects of the patient's medical care. The ICD should be modified in the 10th revision to allow for the separate classification of generalized cardiovascular terminology within the ischemic heart disease category.