Factors predicting death in the ninth decade of life may differ from p
redictors in younger age groups. A prospective study was carried out o
n 210 subjects entering a residential home at the age of 68 to 79 year
s and of 287 subjects aged greater than or equal to 80 years who inclu
ded 91 survivors from the first group; all subjects were followed unti
l 78% of them had died. A Cox analysis was carried out with death as e
nd point and 13 potential risk factors as covariates. Mildly impaired
mobility at entry, defined as the need for help to walk 300-400 yards
for various reasons, smoking, bacteriuria, and presence of ECG abnorma
lities were significant death risk predictors before age 80. Beyond th
is age, only mildly impaired mobility and serum cholesterol levels les
s than or equal to 5.9 mmol/L, as compared with levels greater than or
equal to 8.0 mmol/L, remained significant. Higher hematocrit levels w
ere predictors of survival before and after age 80. Systolic blood pre
ssure, age, sex, weight, and socioeconomic status had no effect in eit
her group. The data show that survival after age 80 is related only to
adequate physical mobility and high hematocrit and cholesterol levels
, regardless of the levels of other common risk factors.