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Outcome evaluation of health promotion/life style change

Outcome evaluation of health promotion/life style change. Wei-Chu Chie. Health promotion. Primary prevention life style change education and health behavior. Three elements for health promotion. Experiment unit Individual or group (cluster), usually healthy Treatments education

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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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