PREDICTING HOSPITAL COSTS AMONG OLDER DECEDENTS OVER TIME

To explain the variation in total real hospital costs among elderly pa tients who died between 1984 and 1991, a cohort analytic study of the nationally representative sample of elderly subjects included in the L ongitudinal Study on Aging (N = 7,527) was carried out. The cohort com prised the subset of 1,778 community-dwelling Americans who were age 7 0 years and older in 1984, had one or more subsequent hospital episode s, and died by 1991. Hospital charges for 1984 through 1991 were taken from the Medicare Automated Data Retrieval System, Annual hospital ch arges were adjusted for inflation (restated in 1984 dollars) using the hospital market basket component of the consumer price index. The nat ural logarithm of aggregated real charges was used in the analysis. Me an total real hospital charges were $24,956 (SD = $27,847). A standard multivariable regression model explained 9.7% of the variance in real total hospital charges. After incorporating additional measures refle cting a respondent's distribution (mean and standard deviation) of com orbidities (as measured by the number of ICD-9-CM codes [truncated at five]) during all hospitalizations in the observation window, the caus e of death, and the concentration of charges in the last year of life, the explained variance increased to 29.3%. The most important explana tory factors were the two variables controlling for the distribution o f comorbidity, the variable controlling for population density, and th e dichotomous variable indicating that the patient's death was related to an acute myocardial infarction. Total real hospital resources cons umed by elderly decedents vary substantially. The concentration of res ources consumed in the last year of a respondent's life was only margi nally significant in predicting total real hospital charges over an 8- year observation window.