HEALTHY LIVING HEALTHY LIVING PARTNERSHIPS TO PARTNERSHIPS TO PREVENT DIABETES PREVENT DIABETES (HELP PD): (HELP PD): CHALLENGES OF CHALLENGES OF COMMUNITYCOMMUNITY--BASED BASED TRANSLATIONSTRANSLATIONSJeffrey A. Katula, PhD, MA for the HELP PD Research Group
Department of Health & Exercise Science
Wake Forest University
Department of Epidemiology and Prevention
Wake Forest School of Medicine
Funded by NIDDK R18 DK069901
Society for Behavioral Medicine Annual Conference, April 11-14, 2012, New Orleans, LA
Diabetes Prevention ProgramDiabetes Prevention Program
� Lifestyle weight loss intervention � 58% reduction in
diabetes incidence (Knowler et al., 2002)
� 6.9% weight loss at 6 months
� 4.5% weight loss at 2.8 years (Wing et al., 2004)
� Weight loss dominant determinant of reduced incidence (Hamman et al., 2006)
� Diabetes Prevention Program translation studies
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Diabetes Prevention Diabetes Prevention
Translational ResearchTranslational Research
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Whittemore (2011). Translational Behavioral Medicine.
PurposePurpose
� Although translational studies have
demonstrated meaningful weight loss, no other
RCT has demonstrated reductions in glucose.
� Role of weight loss in glucose reduction unknown.
� Test the mediational role of weight loss in the
impact of the HELP PD lifestyle intervention on
reductions in glucose.
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Healthy Living Partnerships Healthy Living Partnerships
to Prevent Diabetesto Prevent Diabetes
Design RCT
Setting Community-based
Administered by RDs in DEP
Personnel Community Health Workers (CHWs)
Treatment arms Lifestyle Weight Loss
Enhanced Usual Care
Primary Outcome Fasting Blood Glucose
Secondary Outcomes Adiposity, metabolic risk factors,
psychosocial factors
Follow-up 24-months
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Katula et al. (2009) Contemp Clin Trials.
HELP PD InterventionsHELP PD Interventions
� Enhanced Usual Care (EUC)� 2 sessions with a RD during the first 3 months
� Monthly newsletters
�Lifestyle Weight loss (LWL)� Community-based
� DPP-based curriculum and goals
� CHW-led groups
� Phase 1 (6-months): weekly meetings (24 sessions)
� Phase 2 (7-24 months): monthly meetings (18 sessions)
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Katula et al. (2009) Contemp Clin Trials.; Katula et al. (2011). Diabetes Care.
Mediation ModelMediation Model
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Weight Loss
Lifestyle Weight
Loss Intervention
Glucose
Reduction
a b
cc`
c – c` = ab
� Product of coefficients test (ab) (MacKinnon et al., 2007)
� Sobel test
� Covariates: baseline glucose, age, gender, race
� 12 and 24 months
Participant CharacteristicsParticipant Characteristics
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Katula et al. (2011) Diabetes Care.
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Baseline to 12 month change:LWL: -7.3%EUC: -1.4%p<0.001
Percent Weight Loss: 24Percent Weight Loss: 24--
month changemonth change
Baseline to 24 month change:LWL: -5.1%EUC: -0.6%p<0.001
Katula et al. (In review). American Journal of Preventive Medicine
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Baseline to 12 month change:LWL: -4.2 mg/dlEUC: -0.3 mg/dlp = 0.002
Fasting Blood Glucose: 24 Fasting Blood Glucose: 24
month changemonth change
Baseline to 24 month change:LWL: -2.2 mg/dlEUC: 2.1 mg/dlp = 0.002
Katula et al. (In review). American Journal of Preventive Medicine
Mediation Model (12Mediation Model (12--months)months)
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Weight Loss
Lifestyle Weight
Loss Intervention
Glucose
Reduction
a -5.64 (0.65)
p<0.0001
b 0.61 (0.11) p<0.0001
c-2.63 (1.21)
p<0.05c`
0.81 (1.30)p=0.53
Amount of mediation (ab) = -3.44; Z=-4.72; p<0.0001;n = 272
Mediation Model (24Mediation Model (24--months)months)
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Weight Loss
Lifestyle Weight
Loss Intervention
Glucose
Reduction
a -4.52 (0.79)
p<0.0001
b 0.63 (0.10) p<0.0001
c-4.01 (1.38)
p<0.01c`
-1.13 (1.38)p=0.41
Amount of mediation (ab) = -2.85; Z=-4.72; p<0.0001; n = 260
ConclusionsConclusions� Long-term, significant changes� Weight loss (-5.34 kg; -5.11%)
� Glucose (-2.2; ∆-4.3 mg/dl)
� Weight loss fully mediates intervention effect on glucose� 69% effect at 12 months
� 72% effect at 24 months
� Supports DPP findings (WL � incidence reduction)
� Glucose reduction through weight loss possible in community-based interventions.
� Psychosocial determinants of weight loss and glucose reduction
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AcknowledgementsAcknowledgements
� David C. Goff, Jr., MD, Ph.D.
� Mara Z. Vitolins, DPH, RD
� Michael Lawlor, Ph.D.
� Carolyn Pedley, MD
� Tim Morgan, Ph.D.
� Wei Lang, Ph.D.
� Wake Forest Baptist Hospital Diabetes Care Center
� Community Health Workers
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Glucose reduction across weight Glucose reduction across weight
loss achievement (12loss achievement (12--months)months)
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≤Baseline weight
≥5% Baseline weight
≥10% Baseline weight
Glucose reduction across weight Glucose reduction across weight
loss achievement (24loss achievement (24--months)months)
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≤Baseline weight
≥5% Baseline weight
≥10% Baseline weight
Clinical FollowClinical Follow--upup
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Intervention AdherenceIntervention Adherence
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