Abstract 3194: Clinical Characteristics And Physical Activity Patterns Among The Least-fit And The Next-least-fit Quintile Of Individuals With Cardiovascular Disease
A graded non-linear relationship exists between fitness and all-cause mortality with the most remarkable difference in mortality rates observed between the least-fit (first, Q1) and the next-least-fit (second, Q2) quintile of fitness. The purpose of this study was to compare clinical characteristics, exercise test responses and physical activity patterns in Q1 versus Q2 in individuals with cardiovascular disease (CVD). A total of 5101 consecutive patients referred for clinical exercise testing from 1987 to 2006 were followed for a mean (±SD) of 9.1±5.5 years. All subjects had a history of CVD and/or abnormal exercise test results. Subjects were classified into quintiles of exercise capacity measured in metabolic equivalents (METs) and the first 2 quintiles were compared (Q1: METs <4.2 (n=923); Q2: METs 4.3–5.9 (n=929)). In a subset (n=655), recreational physical activity was assessed using a questionnaire. Q1 had an almost 2-fold increase in age-adjusted relative risk of mortality compared to Q2 (cardiovascular mortality: HR (95% CI): 3.79 (1.73, 8.29) vs. 2.04 (1.9, 4.6), p<0.05; reference group: fittest subjects (Q5, METs >10.0)). Q1 were older (67±9 vs. 64±10 years, p<0.001), had more extensive use of medications and were more likely to have a history of typical angina (35% vs. 28%, p<0.004), myocardial infarction (30% vs. 24%, p=0.003), chronic heart failure (25% vs. 14%, p<0.001), claudication (15% vs. 9%, p<0.001) and stroke (9% vs. 6%, p=0.027) compared to Q2. Prevalence of dyslipidemia, current smoking rates, treatment with ACE-inhibitors, statins and diuretics, and exercise test responses were lower in Q1 versus Q2. Recent (1263±1783 kcal/week vs. 1566±2161 kcal/week, p=0.22) and lifetime (1323±1847 kcal/week vs. 1619±1830 kcal/week, p=0.23) recreational physical activity were not different between the groups. Marked differences in mortality rates between the least-fit and the next-least-fit quintiles appear to be due to a greater severity of disease and comorbidities rather than differences in physical activity patterns. These findings suggest that higher levels of fitness are required to improve survival in individuals with CVD.