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Outcome evaluation of health promotion/life style change

This study evaluates the efficacy and safety of health promotion and lifestyle change interventions in preventing diseases and improving health behaviors. It examines the outcomes and challenges of implementing these interventions in both individual and group settings.

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Outcome evaluation of health promotion/life style change

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  1. Outcome evaluation of health promotion/life style change Wei-Chu Chie

  2. Health promotion • Primary prevention • life style change • education and health behavior

  3. Three elements for health promotion • Experiment unit • Individual or group (cluster), usually healthy • Treatments • education • Evaluation • efficacy • safety: less serious and sometimes overlooked

  4. Basic characteristics • Difficult to follow the rule of randomized controlled double-blinded trials • placebo control with blindness: difficult to make and keep • individual randomization not convenient • requires a large sample size • low incidence of the disease to prevent • low incidence of adverse effects

  5. Major difficulties (1) • No blindness: • Hawthorn effect and information bias • Rater blindness • loyalty to the original randomization • Compliance or adherence • ‘Contamination’ of the control group: • got the intervention content elsewhere or from the treatment group

  6. Major difficulties (2) • Randomization unit • individual: ideal but difficult to implement • group (cluster): easy to implement but has statistical problem

  7. ethical concerns • administered on healthy people • autonomy emphasized: informed consent • safety less serious than immunization and drug, sometimes overlooked

  8. Examples • Diabetes Prevention Program Research Group. Reduction in the incidence or type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393-403. • Brown KS, et al. Outcome evaluation of a high school smoking reduction intervention based on extracurricular activities. Prev Med 2002;35:506-10.

  9. DM: background/goal/hypothesis • Background: • burden of type 2 DM and delayed diagnosis • previous studies of its preventability • Goal/hypothesis: • to determine whether ... /DM is preventable by metformin and lifestyle intervention

  10. DM: study design • Randomized controlled trial • four groups … three • two drugs (one DC due to serious AE) + lifestyle • one placebo + lifestyle • one intensive lifestyle • randomized by individual/stratified by centers • blinded only in the drug vs. placebo groups • primary endpoint evaluated centrally/blind • unaware of the test results in the middle

  11. DM: subjects • High-risk people at 27 centers four steps: • www.bsc.gwu.edu/dpp (the U.S.) • 1996-1999, 3234 subjects (1082:1073:1079) • inclusion: 25 years+, BMI 24 or more, fasting glucose 95-125 mg/dL, 2 hr 75-g GTT 140-199 me/dL; half from minorities • exclusion: taking medicines, illness reducing life expectancy or ability to participate.

  12. DM: exposure/intervention • Group 1: standard lifestyle + metformin 850 mg qd to bid (GI symptoms) • Group 2: … troglitazone … DC • Group 3: intensive lifestyle • Group 4: standard lifestyle + placebo (control)

  13. DM: standard vs. intensive lifestyle • Standard: • written form+individual session • Intensive: • goal: weight reduction 7% • 16-lesson curriculum, one-to-one for 1st 24 wks • healthy low-calorie, low-fat diet • physical activity of moderate intensity • subsequent sessions and group sessions

  14. DM: endpoints • Primary • efficacy: DM/ safety: adverse effects • Secondary • weight, physical activity (MET), glucose • Follow-up • annual o-GTT, semi-annual fasting plasma glucose/symptoms • to planned 5/2001, actually on 3/31/2001 • early stop due to advice from the monitoring board

  15. DM: endpoints • Definition of DM • abnormal o-GTT tests or fasting plasma sugar • confirmation by a second test within 6 weeks • inform the patient and physician • fasting sugar /6 months, HbA1c /year • fasting sugar <140 mg /dL … continue • fasting >= 140 mg/dL … DC and referral

  16. DM: data analysis • Basic characteristics and comparison • for confounding and possible selection bias • Intention-to-treat analysis • primary: time-to-event, survival (life-table) • modified product-limit … cumulative incidence • proportional hazards regression/ subgroup • persons need to treat • secondary: fixed-effects models

  17. DM: major results/discussion • Comparison: Table 1 • Efficacy • primary: Table 2, Figure 2 / subgroup analysis • cumulative incidence P>M>L • secondary: Figure 1, 3, 4 • L has better weight reduction and increase in physical activity, similar or better glucose & HbA1c to M • Safety: Table 3 • M has more GI & L has more MS symptoms

  18. DM: major results/discussion • Discussion • Confounding, selection bias: randomization • Information bias: blindness • Early termination/ ethics • differentiation of diet and physical activity • Sample size and power of test • Conclusion: L>=M>P

  19. Smoking:background/goal/hypothesis • Background: • youth smoking rate and intervention • in-class vs. extra-curricular activities • Goal/hypothesis: • to determine whether... extra-curricular activities can reduce teenage smoking rate

  20. Smoking: study design • Randomized controlled trial • two groups • intervention • usual care (control) • randomized by school (cluster) • no blindness

  21. Smoking: subjects • Waterloo, Canada • Phase 1: 7 school boards/100 schools • teachers/ nurses social influence program • self-preparation materials • high-risk schools • phase 2: 6 boards agreed/ 35 high-schools • 30 schools agreed • matched within school board … pairs

  22. Smoking: subjects • Matching • by size, number and proportion of cohort students • randomized into two groups • pairs: intervention vs. control • grade 9 cohort attending the 30 schools • 30 schools 15:15 • 3028 students…2776... 1563:1465

  23. Smoking: exposure/intervention • Mobilizing staff and students/commitments • A teacher facilitated students, staff, community participants in planning and implementing prevention and cessation activities … tailored to each school • Role of research staff • Budgets

  24. Smoking: endpoints • Primary • efficacy: smoking status • safety: no • Secondary • No • Follow-up • to grade 10

  25. Smoking: endpoints • Definition of smoking status • By questionnaire: • never, • tried once, quit, experimental (< once/week) • regular (weekly) • By CO breath samples

  26. Smoking: data analysis • Basic characteristics and comparison • for confounding and possible selection bias • Intention-to-treat analysis • Primary: • smoking status • subgroup analysis

  27. Smoking: major results/discussion • Comparison: Table 1 • Efficacy • Table 2 • subgroup analysis: • only effective for male non-smoker at grade 8 • No other analyses

  28. DM: major results/discussion • Discussion • Confounding, selection bias: randomization • Information bias: blindness • Sample size and power of test • Limited to one special group • Adverse effects not analyzed • Cost? • Conclusion: limited!

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