Standard Expected Years of Life Lost as a Neglected Index for Calculating the Burden of Premature Mortality due to Middle East Respiratory Syndrome

ortality rates such as case fatality rate, disease- or
cause-specific mortality rate, and proportionate mor-
tality have frequently been used to determine the relative
importance of different causes of death and to estimate the
extent of a public health problem.
1,2
Although all of these
indexes are useful and important in estimating health sta-
tus, they often fail to calculate the overall burden of pre-
mature mortality related to a common or rare disease in
certain populations. One of the popular indexes for esti-
mating the burden of disease is disability-adjusted life years
(DALYs). This index is based on standard expected years of
life lost due to premature mortality (SEYLL) and years lost
due to disability (YLD). An index of disability-adjusted life
years is the sum of standard expected years of life lost and
years lost due to disability. Because the latter is generally
difficult to measure, owing to often poor disability data,
standard expected years of life lost is sometimes reported
alone, as it is based on mortality, which in most countries is
reasonably well documented.
3
In recent years, standard
expected years of life lost as a component of disability-
adjusted life years for quantifying the burden of disease is
increasingly being used to set priorities and guidelines re-
garding health problems and to plan for health intervention
programs.
1
Standard expected years of life lost is measured
by subtracting the age at death and standardized life ex-
pectancy—the highest level of standard life expectancy in
2000 belongs to men (with 80 years expected lifespan) and
women (with 82.5 years expected lifespan) from Japan,
based on levels 25 and 26 of the West model from Coal and
Demeny tables
4
—for the same age and the same sex, and,
specifically, the set of lost life due to a disease in a com-
munity will be the simple addition of standard expected
years of life lost for people who died in that community,
using the following formula: