Long-term risk projection and its application to nephrology research.

Measures of kidney disease burden or risk estimates in nephrology research have primarily focused on the concepts of prevalence, annual incidence or relatively short-term risk such as five or ten-year risk. The concept of long-term risk is rarely used in nephrology research. This paper focuses on two long-term risk measures-lifetime risk and life expectancy. Lifetime risk is an epidemiologic measure that expresses the probability that a person who is currently free of the condition will acquire it at some time during the remainder of their expected lifespan. Life expectancy is the expected number of years of life remaining for a given group of individuals at a specified age. Key data required for estimation of lifetime risk and life expectancy are disease incidence and mortality derived by considering age in the time scale in a longitudinal study. Lifetime risks can be estimated from incidence and mortality rates derived from prospective studies whereas mortality rates are required to estimate life expectancy. Although short-term risks are important, long-term risk can be particularly beneficial for future prediction of the burden of kidney disease, and to assist in health planning and public education.