Severity of symptoms was defined as the person’s
ability to perform normal daily activities in
spite of symptoms and was measured by using the
Specific Activity Scale (SAS).34 A series of 5 questions
is asked by an interviewer to rate the respondent’s
ability to complete specific activities that are
ranked by metabolic expenditure. Subjects are
classified from Class I (fully functional) to Class IV
(severely compromised). The SAS has a reproducibility
of 73% (reliability) and is a better predictor
of a person’s degree of disability from cardiovascular
disease than is the New York Heart Association
classification system (validity).34 These data were
obtained during hospitalization, but patients were
asked to respond based on their functional abilities
just before hospital admission.