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Enhancing fitness in older overweight vets with impaired fasting glucose
Miriam C. Morey, PhD
Durham VA Medical Center, Durham, NC
Funding Period: July 2008 - June 2011
Rates of diabetes continue to increase in this country and are responsible for a disproportionate utilization of health care expenditures. Increasing trends in yearly prevalence rates of diabetes suggest that prediabetes is becoming more common among users of VA for health care. Obesity also continues to rise in VA. The VA has aggressively addressed increases in diabetes, prediabetes, and obesity with implementation of diabetes education and weight management programs and performance measures aimed at optimizing health care in these patients. The VA National Center for Health Promotion (NCP) has instituted several initiatives aimed at promoting physical activity (PA) but implementations of these initiatives vary widely depending upon personnel, equipment, and facilities availability. Building on a successful home-based PA counseling research program, we developed the Enhanced Fitness Study.
The primary objective of the Enhanced Fitness study was to improve glycemic control in older, overweight adults with impaired fasting glucose receiving primary care at the Durham VA. We hypothesized that individuals receiving intensive PA counseling would have significantly improved insulin action, as indicated by fasting insulin, fasting glucose, and by the calculated homeostasis model assessment (HOMA) of insulin resistance, than individuals receiving usual primary care (UC). Other outcomes included comparisons between intensive PA counseling against UC for secondary outcomes of glycemic control (Hemoglobin A1c, metabolic syndrome score), PA, physical function, and health related quality of life.
Our study design included an adaptive randomization which reallocated individuals to higher or lower doses of telephone counseling at three months. This design would allow us to compare costs and outcomes based on different levels of telephone counseling.
Finally we proposed a "train the trainers" approach to teach PA counseling methods developed for this study to other health care practitioners.
We employed a randomized clinical trial with an adaptive randomization design. Veterans ages 60 and over, not regularly exercising, with a body mass index between 25 and 45, and a fasting glucose between 100 and 125 mg/dl were included in this study (n=302). They were randomized to receive high intensity PA counseling or UC. The PA counseling consisted of: (1) in-person baseline counseling, (2) primary care provider endorsement at next clinic visit, (3) telephone counseling for one-year, (4) automated telephone primary care provider endorsement four times during the year, and (5) tailored quarterly mailed reports. A MOVE! consult was submitted for study participants in both arms. At three months, individuals in the PA counseling arm were randomly reassigned to higher or lower doses of PA counseling for the remainder of the study.
The average age of the sample was 67 with a range of 60 to 89. Forty-six percent of the sample had only a high school degree or less. The most frequently reported comorbidities were hypertension (72%) and arthritis (52%). Of 302 patients randomized, 262 (86.8%) of the sample completed the 12-month follow-up visit.
There were no significant differences between PA counseling and UC over time for any of the glycemic indicators. Both groups had declines over time of approximately 6% in fasting blood glucose, p< 0.001. These declines were not sufficient to affect the change in HOMA scores due to fluctuations in insulin over time. HbA1c remained stable throughout the year.
Walking and other endurance physical activity increased significantly over time for the PA counseling group from an average 73 minutes per week at baseline to an average 133 minutes per week at 12-months (+82%) in comparison to the UC group whose endurance PA remained constant from 115 minutes per week at baseline to 112 minutes per week at 12-months, p<0.0001 for between group difference controlling for baseline PA. The prevalence of individuals meeting the goal of 150 minutes of endurance exercise increased in the PA counseling group over time from 16% to 42% in contrast to UC whose prevalence of individuals meeting the 150 minute per week marker was stable over time, OR=1.65(1.08,2.53) for meeting or not meeting goals between groups. Both groups increased strength training activities over time with no between group differences noted. No changes were noted for other secondary outcomes relating to health quality of life or physical function.
The JAMA recently published a meta-analysis of the impact of home-based versus structured exercise in Type II diabetes. They concluded that PA counseling alone did not have a positive impact on their primary outcome of HemA1C. Our study confirms this finding in a VA population and points towards the higher chronic disease burden that Veterans possess as a possible impediment to achieving evidence-based levels of PA necessary to obtain certain health benefits. Further research is needed to optimize health promoting strategies for PA for Veterans.
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DRA: Aging, Older Veterans' Health and Care, Health Systems, Diabetes and Other Endocrine Disorders
DRE: Treatment - Efficacy/Effectiveness Clinical Trial, Treatment - Observational, Prevention
Keywords: Exercise, Obesity, Outcomes
MeSH Terms: none