Life expectancy of persons with chronic disabilities.

The life expectancy is an important summary measure of an individual's prognosis for survival. The life table is the preferred method for computing life expectancies, but it is not always feasible. We show that for several chronic disabilities, the logarithms of the age-specific mortality ratios (relative to the general population) decline linearly with age, reaching parity at age 85 or older. This, combined with a standard modeling of an individual's current mortality rate, yields a set of age-specific mortality rates that can be used to produce a "customized" life table. The life expectancy is then immediately available. In a series of empirical comparisons the method performed better than an assumption of constant excess death rate (EDR), and much better than one of constant mortality ratio (MR). The method may be useful for a variety of non-progressive disabilities, such as cerebral palsy and injuries of the brain or spinal cord.