In 1948, the World Health Organisation
declared health to be “a state of complete physical,
mental and social well-being, and not
merely the absence of disease” (WHO 1978).
Today, any evaluation of a new treatment
should include evidence of its impact on health
and quality of life (Jackowski and Guyatt
2003). Quality of life is a normative concept
that could mean different things to different
people (Fayers and David 2000; Cella and
Nowinski 2002). Within health outcome research,
the concept has been compiled to focus
on those aspects that are more directly affected
by a health condition and facets relating to
factors such as economic status or social
surroundings have been excluded. This confined
concept is called “health-related quality of
life” (HRQL) and it has been defined to include
the perception of an individual of his or her
degree of physical, psychological and social
well-being and the effects that illness and treatment
have on daily life (Jette 1993; Muldoon
et al. 1998; Patrick and Chiang 2000). It is
considered especially important to study
HRQL in groups with chronic conditions when
the goal of care is “to make the patient’s life as
comfortable, functional and satisfying as
possible” (Sullivan et al. 1999)