Diabetes, Vol 45, Issue 1 79-85, Copyright © 1996 by American Diabetes Association
Effect of risk factors on exercise capacity in NIDDM
RO Estacio, EE Wolfel, JG Regensteiner, B Jeffers, EP Havranek, S Savage and RW Schrier
Department of General Internal Medicine, University of Colorado Health Sciences Center, Denver, USA.
Exercise capacity has been used as a noninvasive parameter for predicting
cardiovascular events. It is known that diabetic patients have an impaired
exercise capacity when compared with nondiabetic age-matched control
subjects, but the risk factors associated with this impairment have not
been thoroughly analyzed. A total of 453 male and female NIDDM patients who
underwent graded exercise testing with expired gas analysis were studied to
determine the possible influences of demographic and cardiac risk factors
on exercise capacity. Univariate and multiple linear regression analyses
were performed on baseline patient characteristics with respect to peak
oxygen consumption (VO2). In the regression analyses, African-American race
was strongly associated with a decrease in peak VO2; the difference in
means between African-Americans and other subjects for men was -2.50
ml.kg-1.min-1 (-4.28, -0.07, 95% CI) (P < 0.006) and for women was -2.96
ml.kg-1.min-1 (-4.45, -1.47) (P < 0.0002). Univariate analyses revealed
that African-American subjects had increased prevalence, longer duration,
and higher systolic and diastolic hypertension than the non-Hispanic and
Hispanic whites. Other independent predictors of peak VO2 (reported as
change in peak VO2 in milliliters per kilogram per minute) were BMI (men:
-0.39 kg/m2 [-0.52, -0.29], P < 0.0001; women: -0.39 kg/m2 [-0.48,
-0.31], P < 0.0001), age (men: -0.16/year [-0.23, -0.09], P < 0.0001;
women: -0.17/year [-0.24, -0.11], P < 0.0001), baseline resting systolic
blood pressure (men: -0.03/mmHg [-0.06, -0.01], P < 0.05; women:
-0.03/mmHg (-0.06, -0.01)f1p4< 0.05), and pack-years smoking (men:
-0.04/pack-years [-0.04, -0.01], P < 0.01; women: -0.04/pack-years
[-0.07, -0.01], P < 0.0001). Thus, in this large NIDDM study, weight
loss, smoking cessation, and aggressive blood pressure control,
particularly in African-Americans with NIDDM, would appear to be important
in improving exercise capacity and potentially improving the increased
cardiovascular mortality associated with an impaired exercise capacity.