Mortality rates level off at older ages. Age trajectories of stroke case-fatality rates were studied with the aim of investigating prevalence of this phenomenon, specifically in case-fatality rates at older ages.
A registry of all hospitalized stroke patients in Denmark included 40,155 patients with evaluations of stroke severity, computed tomography, and cardiovascular risk factors. Data on mortality were used to construct age trajectories of 3-day, 1-week, 1-month, and 1-year case-fatality rates in men and women.
Of the 40,155 patients, 19,301 (48%) were women (mean age, 74.5 years) and 20,854 (52%) were men (mean age, 69.7 years). In both women and men, 3-day case-fatality rates leveled off, beginning in the patients' mid-70s. In women, 1-week case-fatality rates leveled off further in their early 80s, whereas in men, 1-week case-fatality rates accelerated with age. One-month and 1-year case-fatality rates accelerated with age for both sexes.
It is an apparent paradox that case-fatality rates in the acute state of stroke level off at the highest ages. Heterogeneity, innate or acquired, in regard to survival capacity may explain the phenomenon.