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Cardiovascular Events in a Physical Activity Intervention Compared With a Successful Aging Intervention - The LIFE Study Randomized Trial ..... aged 70 to 89 years able to walk 400 m.
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Wed Jul 6, 2016
from full study Discussion below -
"Guidelines for PA for older adults include at least 150 minutes/week of moderate-intensity aerobic activity with weight training.23 The LIFE intervention meets these guidelines and proved to be safe and efficacious for the prevention of major mobility disability. The lack of association between increased PA and reduced CVD found here should not detract from efforts to promote a program of sustained walking and weight training in frail older adults."
"Previous trials of activity in older adults have focused on intermediate outcomes such as lowering of blood pressure, weight, and improving function.23,24 In adults with type 2 diabetes, the Look AHEAD (Action for Health for Diabetes) study tested whether a lifestyle intervention that included sustained PA with weight loss could reduce CVD events. While findings were negative for the primary CVD outcome,25 rates of disability were reduced.24 Together, these studies suggest that physical activity should be recommended for improving quality of the remaining years of life."
"There are several potential explanations for a lack of CVD reduction in the LIFE study. It is possible that the dose of activity was of suboptimal duration or intensity. Given the high burden of CVD, it is also possible that it was too late for this high-risk group to benefit. We also noted that both the SA and PA groups became more physically active by self-report, although only the PA group by actigraphy.10 Potentially the contrast between the PA and SA groups was less than if a completely sedentary comparator had been used. It is also possible that the more frequent contact biased the PA group to report more events to the masked assessors or that PA could have precipitated some events in this vulnerable population. In the analysis stratified by SPPB score, when we excluded the symptomatic outcomes in the limited outcome, the difference by SPPB score was not statistically significant."
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Moderate exercise may not cut heart attack risk for elderly
By Kathryn Doyle
(Reuters Health) - For people over age 70, starting a twice-weekly walking program didn't lower the odds of heart attack or stroke over the next two years in a U.S. study.
"We had hoped to see a trend for reduced heart disease events, given the strong positive finding for reduced mobility disability, previously published in JAMA," said lead author Dr. Anne B. Newman, director of the University of Pittsburgh Center for Aging and Population Health.
But in this study there was no difference between doing the physical activity and just receiving health education, Newman told Reuters Health by email.
The researchers randomly assigned 1,600 people aged 70 to 89 years who were able to walk at least 400 meters to either a physical activity program or a "successful aging" educational program. Those in the physical activity group aimed for 150 minutes of walking each week plus strength, flexibility and balance training, with two health center visits per week.
Those in the successful aging group attended weekly workshops for the first 26 weeks and monthly sessions thereafter, but there was no exercise component.
Participants self-reported any history of heart attack, heart failure or stroke, and had health assessment clinic visits every six months for an average of about two and a half years.
During that time, 121 of the 818 physical activity participants suffered a cardiovascular event like heart attack or stroke, as did 113 of the 817 successful aging participants, according to the results in JAMA Cardiology.
"The lack of a difference could mean that physical activity needs to start earlier in life to prevent cardiovascular disease or it could mean that more exercise is needed than what we provided in this study," Newman said. "It is important to recognize that these were frail older adults at high risk for disability."
This level of activity can improve mobility, as found in a previous study, she noted.
"The major benefit of a walking program for people over 70 is in reducing disability and improving mobility," she said.
Muscles can respond to exercise in people well past 90 years of age, so it is never too late to start improving function, she said.
"The benefits probably do not diminish, but the ability to exercise starts to decline in most people in their 40's," as the rate of injury increases, Newman said. "Our program was safe and effective for preventing mobility disability, and was well tolerated by frail older adults over age 70 for an average of two and a half years."
"Studies of cardiac rehab do show that recurrent heart attacks are prevented with exercise," she said.
Not smoking and following a healthy diet can also reduce cardiovascular risk, she said.
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Cardiovascular Events in a Physical Activity Intervention Compared With a Successful Aging InterventionThe LIFE Study Randomized Trial FREE ONLINE FIRST
JAMA Cardiol. Published online June 29, 2016
Anne B. Newman, MD, MPH1; John A. Dodson, MD2; Timothy S. Church, MD, PhD3; Thomas W. Buford, PhD4; Roger A. Fielding, PhD5; Stephen Kritchevsky, PhD6; Daniel Beavers, PhD, MS6; Marco Pahor, MD4; Randall S. Stafford, MD, PhD7; Anita D. Szady, MD4; Walter T. Ambrosius, PhD6; Mary M. McDermott, MD8 ; for the LIFE Study Group
open access - http://cardiology.jamanetwork.com/article.aspx?articleid=2530563
ABSTRACT
Importance Whether sustained physical activity prevents cardiovascular disease (CVD) events in older adults is uncertain.
Objective To test the hypothesis that cardiovascular morbidity and mortality would be reduced in participants in a long-term physical activity program.
Design, Setting, and Participants The Lifestyle Interventions and Independence for Elders (LIFE) study was a multicenter, randomized trial. Participants were recruited at 8 centers in the United States. We randomized 1635 sedentary men and women aged 70 to 89 years with a Short Physical Performance Battery (SPPB) score of 9 or less but able to walk 400 m.
Interventions The physcial activity (PA) intervention was a structured moderate-intensity program, predominantly walking 2 times per week on site for 2.6 years on average. The successful aging intervention consisted of weekly health education sessions for 6 months, then monthly.
Main Outcomes and Measures Total CVD events, including fatal and nonfatal myocardial infarction, angina, stroke, transient ischemic attack, and peripheral artery disease, were adjudicated by committee, and silent myocardial infarction was assessed by serial electrocardiograms. A limited outcome of myocardial infarction, stroke, and CVD death was also studied. Outcome assessors and adjudicators were blinded to intervention assignment.
Results The 1635 LIFE study participants were predominantly women (67%), with a mean (SD) age of 78.7 (5.2) years; 20% were African-American, 6% were Hispanic or other race or ethnic group, and 74% were non-Latino white. New CVD events occurred in 121 of 818 PA participants (14.8%) and 113 of 817 successful aging participants (13.8%) (HR, 1.10; 95% CI, 0.85-1.42).
For the more focused combined outcome of myocardial infarction, stroke, or cardiovascular death, rates were 4.6% in PA and 4.5% in the successful aging group (HR, 1.05; 95% CI, 0.67-1.66).
Among frailer participants with an SPPB score less than 8, total CVD rates were 14.2% in PA vs 17.7% in successful aging (HR, 0.76; 95% CI, 0.52-1.10), compared with 15.3% vs 10.5% among those with an SPPB score of 8 or 9 (HR, 1.59; 95% CI, 1.09-2.30) (P for interaction = .006). With the limited end point, the interaction was not significant (P = .59), with an HR of 0.94 (95% CI, 0.50-1.75) for an SPPB score less than 8 and an HR of 1.20 (95% CI, 0.62-2.34) for an SBBP score of 8 or 9.
from Results - "Total incident CVD occurred in 14.3% overall, with 121 of 818 PA participants (14.8%) and 113 of 817 SA participants (13.8%) or 6.2 vs 5.6 events per 100 person-years (HR, 1.10; 95% CI, 0.85-1.42). For the more limited combined outcome of MI, stroke, or cardiovascular death, rates were 38 (4.6%) in the PA group and 37 (4.5%) in the SA group or 1.8 vs 1.7 events per 100 person-years (HR, 1.05; 95% CI, 0.67-1.66). There was no difference in the rate of individual events between intervention groups (Table 2 and Figure 1).
In prespecified subgroup analyses, there were no differences in rates of incident vs recurrent CVD (Figure 2). Among participants with an SPPB score less than 8, CVD rates were 14.2% in PA vs 17.7% in SA (HR, 0.76; 95% CI, 0.52-1.10), compared with 15.3% vs 10.5% (HR, 1.59; 95% CI, 1.09-2.30) among those with an SPPB score of 8 or 9 (P for interaction = .006). The interaction was not significantly different for the more limited composite end point of MI, stroke, or CVD death. For the limited outcome, among participants with an SPPB score less than 8, CVD rates were 5.4% in PA vs 5.6% in SA (HR, 0.94; 95% CI, 0.50-1.75), compared with 4.1% vs 3.6% (HR, 1.20; 95% CI, 0.62-2.34) among those with an SPPB score of 8 or 9 (P for interaction = .59) (eFigures 2 and 3 in the Supplement)."
Conclusions and Relevance Among participants in the LIFE Study, an aerobically based, moderately intensive PA program was not associated with reduced cardiovascular events in spite of the intervention's previously documented ability to prevent mobility disability.
INTRODUCTION
There are few randomized clinical trials testing the ability of physical activity to prevent cardiovascular disease (CVD) events. Many observational studies demonstrate that greater physical activity (PA) is associated with lower rates of incident and recurrent myocardial infarction (MI) across a spectrum of age.1- 3 In clinical trials, physical activity interventions have been shown to slow the progression of coronary artery disease4,5 and can prolong event-free survival in patients undergoing stent placement.6,7 Cardiac rehabilitation trials show reduction in cardiovascular events for patients with recent cardiovascular illness, although most trials include risk-factor modification in addition to exercise training, making it difficult to isolate the effect of physical activity. Guidelines8,9extend recommendations for 150 minutes of moderate activity per week for middle-aged adults to older adults based on studies to date. However, these trials have not included many frail older adults who are at highest risk for CVD and disability. Thus, many questions remain as to the optimal frequency, intensity, and modality of physical activity for older adults. To our knowledge, whether a physical activity intervention can prevent CVD events in older, functionally limited individuals is unknown.
The Lifestyle Independence and Interventions for Elders (LIFE) Study compared PA with health education and showed that a structured PA program can prevent mobility disability in older adults with functional limitations. In the trial, incident major mobility disability occurred in 30.1% of the PA group and 35.5% of the health education group (hazard ratio [HR], 0.82; 95% CI, 0.69-0.98).10 As a tertiary outcome, we compared cardiovascular event rates between the 2 study groups. The PA intervention was conducted over an average of 2.5 years and included moderate aerobic activity, mostly walking, of at least 150 minutes per week; thus, the study can be viewed as an evaluation of the benefits of guidelines for prevention of CVD events.8,9
DISCUSSION
Among participants in the LIFE Study, an aerobically based, moderately intensive PA program was not associated with reduced cardiovascular events. Participants in the LIFE study had a substantial baseline burden of prevalent CVD and cardiovascular risk factors and had a high rate of cardiovascular events (14.3%) during the 2.6 years of follow-up in the LIFE Study. In what is, to our knowledge, the only randomized trial of sustained PA in functionally limited older adults, the benefits of activity appear to be primarily reduced mobility disability10 and perhaps improved cognition.20
The lack of benefit for CVS was similar in most subgroups including the one-third of the cohort with prevalent CVD at baseline. Individuals with poorer physical performance at baseline, defined as an SPPB score less than 8, had a more favorable benefit from PA for the outcome of CVD than those with a more moderate level of SPPB, as indicated by the statistically significant interaction term. In the LIFE study, a pattern of relatively more favorable benefit for older and more poorly functioning individuals was observed for the primary outcome of major mobility disability10and for other secondary outcomes.10,21,22 In the case of the CVD outcome, the subgroup with less severe impairment had a higher rate of events in the PA group when compared with the SA/health education group. Further evaluation of the characteristics and activity of the SPPB 8 to 9 subgroup did not provide an obvious explanation for the higher event rate with PA in the high SPPB subgroup (8-9) vs the low SPPB subgroup (≤7). Participants with a higher baseline SPPB score reported a lower level of exertion with activity and had a similar relative increase in activity compared with the control group, as did the low SPPB subgroup. Of note, this interaction was not significant when CVD events were restricted to MI, stroke, and CVD death. While prespecified, these subgroup comparisons were meant to be hypothesis-generating rather than designed to test specific hypotheses.
There are several potential explanations for a lack of CVD reduction in the LIFE study. It is possible that the dose of activity was of suboptimal duration or intensity. Given the high burden of CVD, it is also possible that it was too late for this high-risk group to benefit. We also noted that both the SA and PA groups became more physically active by self-report, although only the PA group by actigraphy.10 Potentially the contrast between the PA and SA groups was less than if a completely sedentary comparator had been used. It is also possible that the more frequent contact biased the PA group to report more events to the masked assessors or that PA could have precipitated some events in this vulnerable population. In the analysis stratified by SPPB score, when we excluded the symptomatic outcomes in the limited outcome, the difference by SPPB score was not statistically significant.
There are several important limitations to this study. Follow-up was only 2.6 years on average. Statistical power was limited to detect small differences in rates or in subgroups.
Previous trials of activity in older adults have focused on intermediate outcomes such as lowering of blood pressure, weight, and improving function.23,24 In adults with type 2 diabetes, the Look AHEAD (Action for Health for Diabetes) study tested whether a lifestyle intervention that included sustained PA with weight loss could reduce CVD events. While findings were negative for the primary CVD outcome,25 rates of disability were reduced.24 Together, these studies suggest that physical activity should be recommended for improving quality of the remaining years of life.
CONCLUSIONS
Guidelines for PA for older adults include at least 150 minutes/week of moderate-intensity aerobic activity with weight training.23 The LIFE intervention meets these guidelines and proved to be safe and efficacious for the prevention of major mobility disability. The lack of association between increased PA and reduced CVD found here should not detract from efforts to promote a program of sustained walking and weight training in frail older adults.
METHODS
The LIFE study was a multicenter, single-blinded, randomized trial of PA compared with health education conducted at 8 field centers across the United States (University of Florida, Gainesville and Jacksonville; Northwestern University, Chicago, Illinois; Pennington Biomedical Research Center, Baton Rouge, Louisiana; University of Pittsburgh, Pittsburgh, Pennsylvania; Stanford University, Stanford, California; Tufts University, Boston, Massachusetts; Wake Forest School of Medicine, Winston-Salem, North Carolina; and Yale University, New Haven, Connecticut) between February 2010 and December 2013. The Administrative Coordinating Center was located at the University of Florida, Gainesville, and the Data Management, Analysis, and Quality Control Center was at Wake Forest School of Medicine. The field centers included rural, suburban, and urban communities.
Details of the trial design, recruitment, and primary outcome have been published previously (eFigure 1 in the Supplement).10- 12 Men and women aged 70 to 89 years were eligible if they were sedentary, defined as reporting less than 20 minutes/week in the past month performing regular PA and reporting less than 125 minutes/week of moderate PA; were at high risk for mobility disability based on objective lower extremity functional limitations as measured by the Short Physical Performance Battery (SPPB)13 score of 9 or lower of a total of 12 (45% of participants were targeted to have an SPPB score <8); could walk 400 m in 15 minutes or less without sitting, leaning, or the help of another person or walker; had no major cognitive impairment (Modified Mini-Mental State Examination14 1.5 SDs below education- and race/ethnicity-specific norms); and could safely participate in the intervention as determined by medical history, a practitioner-administered physical examination, and resting electrocardiogram (ECG) reading. The primary outcome of major mobility disability was defined as the inability to complete a 400 m walk test within 15 minutes without sitting and without the help of another person or walker.10,11 The study protocol was approved by the institutional review boards at all participating sites. Written informed consent was obtained from all study participants. The trial was monitored by a data safety monitoring board appointed by the National Institute on Aging.
Randomization
Participants were randomized to a PA or to a successful aging (SA) program via a secure, internet-based data management system using a permuted block algorithm (with random block lengths), stratified by field center and sex. Both groups received an initial individual 45-minute face-to-face introductory session by a health educator who described the intervention, communicated expectations, and answered questions.
RESULTS
The 1635 LIFE study participants were predominantly women (67%), with a mean (SD) age of 78.7 (5.2) years; 288 (20%) were African American, 108 (6%) were Hispanic or other race/ethnic group, and 1239 (74%) were non-Latino white. The overall prevalence of CVD at baseline was 129 (8%) for MI, 104 (6.5%) for stroke, and 71 (4.2%) for heart failure with an overall baseline prevalence of 30%. Hypertension and diabetes were common (1151 [69%] and 415 [26%], respectively), while only 50 (3%) currently smoked cigarettes. Mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) was 30 (5.5). Lipid levels, blood pressure, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol varied. Reflecting a high risk of disability, the mean SBBP was 7.4. These characteristics were balanced between the intervention groups (Table 1).
Total incident CVD occurred in 14.3% overall, with 121 of 818 PA participants (14.8%) and 113 of 817 SA participants (13.8%) or 6.2 vs 5.6 events per 100 person-years (HR, 1.10; 95% CI, 0.85-1.42). For the more limited combined outcome of MI, stroke, or cardiovascular death, rates were 38 (4.6%) in the PA group and 37 (4.5%) in the SA group or 1.8 vs 1.7 events per 100 person-years (HR, 1.05; 95% CI, 0.67-1.66). There was no difference in the rate of individual events between intervention groups (Table 2 and Figure 1).
In prespecified subgroup analyses, there were no differences in rates of incident vs recurrent CVD (Figure 2). Among participants with an SPPB score less than 8, CVD rates were 14.2% in PA vs 17.7% in SA (HR, 0.76; 95% CI, 0.52-1.10), compared with 15.3% vs 10.5% (HR, 1.59; 95% CI, 1.09-2.30) among those with an SPPB score of 8 or 9 (P for interaction = .006). The interaction was not significantly different for the more limited composite end point of MI, stroke, or CVD death. For the limited outcome, among participants with an SPPB score less than 8, CVD rates were 5.4% in PA vs 5.6% in SA (HR, 0.94; 95% CI, 0.50-1.75), compared with 4.1% vs 3.6% (HR, 1.20; 95% CI, 0.62-2.34) among those with an SPPB score of 8 or 9 (P for interaction = .59) (eFigures 2 and 3 in the Supplement).
Because the observed effect of the intervention on CVD outcomes was marginally significant in lower vs higher SPPB subgroup, we examined the demographic, health characteristics, and types of CVD events by SPPB subgroup. We also examined the level of PA and level of exertion with PA during the trial by intervention group as well as SPPB subgroup (eTable in the Supplement). There were no differences in baseline characteristics by SPPB subgroup such as prevalent CVD, CVD risk factors, physical activity, or perceived level of exertion at baseline. There were more silent MIs by ECG in the higher SPPB subgroup but not more cardiovascular procedures, and this did not explain the relatively higher risk in the higher SPPB subgroup. Over the course of the study, higher SPPB subgroups had higher measured activity and lower perceived exertion than the lower SBBP subgroups in both the PA group and the SA group (eFigure 4 in the Supplement).
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