Introduction

In recent years there has been a considerable increase in the size of the elderly population (i.e., those over 64 years of age) in the USA, with this trend expected to continue into the twenty–first century (Anand et al. 1990). From 1900 to 1990, the number of elderly American citizens increased 10-fold, rising from 3.1 million to 31.4 million, and their proportion of the total population has tripled, rising from 4.1% to 12.6%. By 1996, 20% of the US population was older than 65 years of age (Latos 1996), while in developed countries overall those aged 65 or older make up 14% of the population (Gelbard, Haub, and Kent 1999). US men who survive to age 65 can expect to live another 16 years on average; US women who are age 65 can expect to live another 19 years (Gelbard et al. 1999).

The aging of the population will play an important and controversial role in the distribution and provision of health resources. On the one hand, the existing discrepancy between the percentage of elderly in the population and the high proportion of health care resources that they consume (Rowe, Grossman, and Bond 1987) will contribute to an increase in health care spending (Chelluri et al. 1993). On the other hand, the lack of information about the influence of age on outcomes suggests the need to readdress using age as a criterion for efficient distribution of health care resources (Callahan 1987; Veatch 1988; Hunt 1993).