Evaluation of a specific activity questionnaire to predict
mortality in men referred for exercise testing
Paul McAuley, PhD,
a
Jonathan Myers, PhD,
b
Joshua Abella, MD,
b
and Victor Froelicher, MD
b
Los Angeles and
Palo Alto, CA
Background
A self-administered symptom questionnaire developed at our institution (Veterans Specific
Activity Questionnaire [VSAQ]) is routinely used to estimate a patient’s exercise capacity to individualize the exercise
test in accordance with current guidelines. This study was performed to evaluate the association of the VSAQ with
all-cause mortality.
Methods
The VSAQ was administered to 1185 consecutive male patients (mean age 58 F 12 years) referred for
exercise testing for clinical reasons. The VSAQ is designed to determine which specific daily activities are associated
with cardiovascular symptoms (fatigue, chest pain, or shortness of breath) to provide an estimate of exercise tolerance
(in metabolic equivalents [METs]) before exercise testing. Patients were classified into 1 of 3 groups according to VSAQ
score: b5 METs, 5 to 8 METs, and N8 METs. The association between exercise capacity estimated by the VSAQ, other clinical
and exercise test variables, and all-cause mortality was assessed by Cox proportional hazards. The mean follow-up
period was 4.5 F 2.9 years.
Results
There were a total of 132 deaths during the follow-up period, resulting in an average annual mortality of 2.7%.
In a multivariate analysis including clinical risk factors and exercise test variables, age-adjusted predictors of mortality, in
rank order, were the VSAQ score in METs, history of chronic heart failure, history of smoking, and diabetes (for VSAQ:
hazard ratio [HR] 0.90, 95% CI 0.83-0.98; for chronic heart failure: HR 2.67; 95% CI 1.51-4.72; for smoking: HR
1.74, 95% CI 1.18-2.57; and for diabetes: HR 1.84, 95% CI 1.15-2.95). Expressed in tertiles, age-adjusted relative
risks for the VSAQ were 1.0, 0.54, and 0.22 ( P for trend b.001). Each 1-MET increase in the VSAQ conferred a 10%
survival benefit.
Conclusions
A simple self-administered symptom questionnaire strongly and independently predicted all-cause
mortality. The VSAQ is a useful adjunct to clinical and exercise test data for stratifying risk in patients undergoing exercise
testing for clinical reasons. (Am Heart J 2006;151:890.e1-890.e7)
The exercise test is a valuable clinical tool which
provides a wealth of diagnostic and prognostic informa-
tion.
1,2
In recent years, exercise capacity has become
increasingly recognized as a strong independent predic-
tor of all-cause mortality.
3-5
Because maximal exercise
testing is not always available, a number of surrogate
measures have been used to estimate exercise tolerance.
These include submaximal walk tests,
6-9
symptom
questionnaires,
10 - 14
and a variety of nonexercise func-
tional tools.
15,16
These have been particularly useful in
multicenter pharmaceutical trials, in which exercise
testing on a large scale is often not performed because of
pragmatic or financial reasons. Although these measures
generally correlate only modestly with measured exer-
cise capacity, some have been shown to have prognostic
value. For example, in the SOLVD trial, the inability to
achieve N300 m in the 6-minute walk test strongly
predicted mortality,
6
and this finding has been confirmed
by subsequent trials in the United States and Europe.
7,8
In
a recent study from WISE, the diagnostic and prognostic
value of the Duke Activity Status Index (DASI),
12
a
functional assessment tool derived from a patients’ ability
to perform daily activities, more strongly predicted
cardiac events than other risk markers; each 1–metabolic
equivalent (MET) increase in DASI score was associated
with an 8% decrease in cardiovascular events.
17
Consensus guidelines published by major organiza-
tions have suggested that the exercise test should be
individualized, and the test duration should fall within a
range of 8 to 12 minutes.
1,2
We originally developed the
Veterans Specific Activity Questionnaire (VSAQ) in an
effort to individualize the exercise test protocol to meet
From the
a
Department of Natural Science, Loyola Marymount University, Los Angeles,
CA, and
b
Cardiology Division, VA Palo Alto Health Care System/Stanford University,
Palo Alto, CA
b
New England Research Institutes, Watertown, MA.
Submitted May 27, 2005; accepted September 15, 2005.
Reprint requests: Jonathan Myers, PhD, Cardiology Division, 111C, VA Palo Alto Health
Care System, 3801 Miranda Avenue, Palo Alto, CA 94304.
E-mail: drj993@aol.com
0002-8703/$ - see front matter
n 2006, Mosby, Inc. All rights reserved.
doi:10.1016/j.ahj.2005.09.017