Physical Activity Mediators and Dietary Habits in Patients at Risk for Peripheral Arterial Disease

Sarah Barnes MS2, AHC Pre-doctoral FellowTracie Collins MD, MPH, Associate Professor of Medicine

Talk OverviewWhat is Peripheral Arterial Disease?Literature ReviewDr. Collins’ walking studyMy survey study

Peripheral Arterial Disease (PAD)

Obstruction of peripheral arteries

AtherosclerosisInflammatory processesStenosisEmbolism or thrombus formation

Leg Symptoms

AtypicalClaudication

Pain or cramping in musclesGoes away at rest

Critical Limb IschemiaSores, wounds or ulcersSlow to heal

Diagnosis at the BedsideAnkle brachial index (ABI)

Systolic ankle blood pressure/systolic arm blood pressure

Risk Factors

SmokingDiabetes MellitusHyperlipidemiaHypertensionAge older than 70 yearsAfrican American

Treatment

Risk Factor ManagementSmoking cessationGlucose controlBlood pressure controlLipid control

MedicationAspirinClopidogrel (Plavix)StatinsCilostazol for claudication

Regular exerciseAngioplastyStents

Why PAD?Walking impairment impacts every day lifeIncreased risk for cardiovascular events Much of treatment focus is on preventing systemic events

PAD and Exercise

Patients with higher daily physical activity have reduced mortality and cardiovascular events

(Garg et. al Circulation 2006)

Patients randomized to supervised treadmill walking program showed greater improvement in community walking ability

(Pilot Study McDermott et. al. Journal of Cardiopulmonary Rehabilitation 2004)

Unsupervised Walking(Collins et. al. Annals of Behavioral Medicine, 2007)

Significant improvement:ABI (P=0.008)

Stair climbing ability:Intervention group 61.2 ±32.8 Control group 40.2 ±30.2 (p=0.02)

Readiness to exercise (PACE Score)4.73 ± 1.3 vs 2.92 ±1.8 (p=0.04)

0.640.660.68

0.70.720.740.760.78

0.80.820.840.86

ABI-B

ABI-F

Intervention

Control

PAD and Diabetes

Patients with PAD and diabetes have poorer lower extremity function than patients with only PAD (Dolan et. al. Diabetes Care 2002)

Diabetic neuropathyGreater cardiovascular disease

Diabetics are less likely to intend to exercise and less likely to actively engage in exercise (Schrop et. al. Journal of Health Care for the Poor and Underserved, 2006)

Self-Managed Walking Improves Function in Patients with Diabetes Mellitus and Peripheral Arterial Disease

• How this study is different• Intervention v. observational• Self-managed v. scheduled sessions• Community walking v. treadmill

• Hypothesis: To determine if self-managed walking therapy results in improved ambulatory function for patients with symptomatic PAD and diabetes mellitus

AssessmentsInitial Telephone Assessment

San Diego ClaudicationQuestionnairePhysical Activity Readiness QuestionnairePatient-Centered Assessment and Counseling for Exercise (PACE) protocol

ABIBaseline Visit

Treadmill Walking testQuestionnaires

Lifestyle and Clinical SurveyWalking Impairment QuestionnaireMedical Outcomes Short Form SurveySelf-EfficacyStanford Exercise BehaviorsGeriatric Depression Scale

PAD Video

Randomization

Randomized

Intervention Control

Bi-weekly Phone CallsRisk Factor ControlExercise Frequency

Self Managed Programone on one: walking behaviors

Reinforcement: 2 walking training sessionsGroup: weekly community walking sessions

Bi-weekly Phone CallsRisk Factor ControlExercise Frequency

PACE scoreWalking Behaviors

3 month and 6 month Follow up Visits

ABITreadmill Walking TestQuestionnaires

Walking Impairment QuestionnaireMedical Outcomes Short Form SurveySelf-EfficacyStanford Exercise BehaviorsGeriatric Depression Scale

Exclusion Criteria

Poorly controlled diabetesHgb A1c > 9.5

Limited ability to complete exercise protocolMajor amputation, vascular surgery planned ect.

Absence of Leg Symptoms

Limited exercise toleranceSevere arthritis, dizziness, angina ect.

PACE score of 1Patients who do not intend to start exercising in the next 6 months

Progress621 participants assessed via telephone

127 eligible

32 randomized

2 completed 6 month follow ups

Physical Activity Mediators and Dietary Habits in Patients at Risk for PAD

PAD and NutritionHigh consumption of fiber containing foods associated with greater mean ABI in males

High consumption of meat associated with low mean ABI (Edinburgh Artery Study, Donnan et. al. American Journal of Clinical Nutrition, 1993)

Positive clinical effects of fish oil, carnitine and vitamin E (Carrero and Grimble British Journal of Nutrition, 2006)

Physical Activity Determinants and Mediators

Physical Activity Determinants and Mediators

BarriersTime Constraints

(leading reason, Strutts, AAOHN Journal, 2002)

Lack of motivationBoredomLack of facilities or access to equipmentCostWeatherLack of encouragement or social support

IncentivesDissatisfaction with weight and appearance

(leading reason, Strutts, AAOHN Journal, 2002)

HabitDecrease stressImprove healthTold by physicianJob requirementsExercise petSpend time with children

Study Methods

Excluded Patients – consented to be contacted for future research

Assess exercise mediators and nutritional habits via telephone or mailed surveys

Compare participants with a PACE score of 1, who do not intend to exercise, to participants with a higher PACE score

AssessmentsLots of Phone Calls!!Demographic informationPACE Physical Activity StatusPACE Nutritional Assessment Form6 Physical Activity Questionnaires

PACE Physical Activity

8 item survey3 stages of readiness to change

Pre-contemplation = 1Not physically active and no intention to exercise in the next 6 months

Contemplation = 2-4Intentions to begin physical activity or not active on a regular basis

Active = 5-8Currently physically active

PACE in Research

Physically Active for Life Project“Feasible” intervention for physicians that improved satisfaction of care (Pinto et. Al. Annals of Behavioral Medicine, 2001)

PACE protocol produces short term increases in physical activity outcomes (Calfas et. al. Preventive Medicine, 1996)

PACE Nutrition

4 item surveysPre-contemplation, Contemplation, Active

Fruit and Vegetable IntakeDietary Fat IntakeCalorie Intake and Weight Management

Physical Activity Questionnaires

1. Processes of Change – cognitive and behavioral processes

Increasing KnowledgeBeing aware of risksCaring about consequences to othersComprehending benefitsIncreasing healthy opportunitiesSubstituting alternativesEnlisting social supportRewarding oneselfCommitting oneselfReminding oneself

2. Confidence (Self-Efficacy)3. Decisional Balance – benefits and barriers4. Social Support5. Outcome Expectations for Exercise – beliefs6. Physical Activity Enjoyment Scale

Physical Activity Questionnaires

Physical Activity Questionnaires in Research

Physical Activity for Life ProjectIntervention had a significant impact on processes of change (Pinto et. al Annals of Behavioral Medicine, 2001)

Processes of Change used in exercise intervention (Marcus et. Al. American Journal of Health Promotion, 1992)

Decisional Balance Questionnaire significantly associated with exercise adoption stage (Marcus et. al. Health Psychology, 1992)

Participants

N = 37Gender

19 Male18 Female

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6

Pace Scores

Part

icip

ants

Nutrition Results

78015, 6

49322, 3, 4

11001

4321Activity Score

Fruits and Vegetables

411015, 6

511102, 3, 4

20001

4321Activity Score

Dietary Fat

106005, 6

414002, 3, 4

20001

4321Activity Score

Calorie Intake

Processes of Change Results

1.5

2

2.5

3

3.5

4

1 2, 3, 4, 5, 6

Pace Scores

Que

stio

nnai

re S

core

s

Increasing know ledge

Being aw are of risks

Caring about consequences

Comprehending benefits

Increasing healthy opportunities

Substituting alternatives

Enlisting social support

Rew arding oneself

Committing oneself

Reminding oneself

Significant Results:Substituting AlternativesCommitting oneself

Decisional Balance

-0.5

0

0.5

1

1.5

2

1 2, 3, 4 5, 6

PACE Score

Que

stio

nnai

re S

core

Significant Results

Processes of ChangeSubstituting Alternatives

Both PACE 1 and PACE 2-4 groups significantly different than PACE 5-6 (p=0.007)

Committing oneselfPACE 1 group significantly different from PACE 5-6 (p=0.044)

Decisional BalanceAll groups significantly different (p=0.004)

Outcome Expectations for ExercisePACE 1 group significantly different from PACE 2-6 (p=0.034)

Difficulties

Subject BiasOnly 2 out of 37 participants with PACE score of 1

Time Constraints25-35 minutes to complete telephone surveys

Mailings – self administeredParticipants forget pages, leave questions blank and/or write in their own answer

Acknowledgements

AHC Office of Clinical ResearchTracie Collins MD MPHColleen Curran MS BiostatisticianADA Study team

Vicky Haines, MA MS3Catherine HookeMarissa Lightbourne MPH MS2Catherine Logan PTEmily Parker PhD

Sources (pictures)

National Heart Lung and Blood Institute (www.nhlbi.nih.gov/health/dci)WikipediaDr. Tracie CollinsOCR Accelerate newsletter September 2006 (www.ahc.umn.edu/ocr)USDA (www.mypyramid.gov)The Age (www.theage.com)