Possible Influence of the Prospective Payment System on the Assignment of Discharge Diagnoses for Coronary Heart Disease

Background The prospective payment system, under which diagnosis-related groups (DRGs) are used to reimburse hospitals for the care of Medicare patients, replaced the fee-for-service method of payment in Rhode Island in 1983 and in Massachusetts in 1985. Changes in financial incentives resulting from the use of the DRG system may have influenced the assignment of discharge diagnostic codes away from those with lower reimbursement toward codes with higher reimbursement. Methods We collected data from the hospital records of patients 35 through 74 years of age who were discharged with codes 410 through 414 (representing various categories of coronary heart disease) of the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). The patients were discharged from seven hospitals in two New England communities (one in Rhode Island and one in Massachusetts) between 1980 and 1988. The rates of diagnosis of various forms of coronary heart disease were determined by studying ICD-9-...