# Presentation: 701487

## BCC TransbehavioralOutcome Assessments

**Lisa Klesges****Geoffrey Williams****Steve Belle**
**December 06, 2001**

## Potential Outcomes

- Criterion
- % of individuals who attain behavior goal
- Reduction in 30 mortality  Woolf, 1999
- Clinical Preventable Burden & Cost Effectiveness Coffield et al., 2001
- Quality adjusted life years saved (QALYs)
- Net cost of service/QALYs

## References

- Woolf, S.H. (1999). The need for perspective in evidence-based medicine.  _JAMA_, _282_, 2358-2365.
- Coffield, Maciosek, McGinnis et al. (2001). Priorities among recommended clinical preventive services. _American Journal of Preventive Medicine_, _21_(1), 1-9.

## Which Interventions Work Best?

- Woolf recommends systematically comparing the relative effectiveness of interventions in preventing disease outcomes
- Treatment of heart disease reduces mortality by 21-33%
- Are these treatments more or less likely to prevent death than smoking cessation or exercise?

## Policy and Personal Implications

**For Policy Makers:** Comparisons are important in terms of reducing number of deaths in the population.
**For Individuals:** Comparisons inform personal choices.

## Projected Outcomes

## Projected Outcomes

## Projected Outcomes

## Calculations

- Population projections were derived by multiplying the number of deaths potentially preventable by the intervention by the preventable fraction
- Preventable fraction=(p[1-RRR])/(RRR+p[1-RRR])
- p=proportion of eligible population that has not received the intervention
- RRR=relative risk reduction

## Calculations

- Reduction of 30 year mortality
- Absolute difference between 30 year cumulative probability of death with and without the intervention
- Cumulative probability of death was derived  from a standard survival calculation for hypothetical cohort of 45-year-old women using annual mortality rates specified in the tables
- Cumulative death rates x RRR = 30 year probability of death with the intervention

## Comments

- Lifestyle changes offer much greater benefits when  compared to disease treatments
- Offers rough approximation of benefits comparing tobacco cessation versus dietary change or regular exercise

## Ratio’s based on Woolf’s data

**Exercise/Tobacco Cessation**
- NNT  = 	1.78
- Preventable deaths =	1.84
**Lipids/Tobacco Cessation**
- NNT =	3.77
- Preventable deaths =	2.48
**Lipids/Exercise**
- NNT =	2.13
- Preventable deaths = 	1.35

## Limitations

- RRRs have wide confidence intervals
- All deaths are not equally preventable
- Model is binary, but health effects are continuous (e.g., exercise, all benefit)
- Assumes complete adherence (unrealistic)
- Total deaths after age 25
- Mortality vs. QALYs or CE

## Clinically Preventable Burden (CPB)

- Proportion of disease and injury prevented if delivered to 100% of the target population
- CPB is the product of the burden of disease targeted by the service and its effectiveness
- Represented as Quality Adjusted Life Years (QALY)

## Cost Effectiveness (CE)

- CE=(costs of prevention-costs averted) divided by the QALYs saved expressed in 1995 dollars
- 13 services CE existed in published studies
- 17 services this was estimated

## CPB and CE

## Priorities Among Services

## Ratios based on CPB 

**Tobacco Cessation/Exercise**
- CPB ratio  =  	1.67
- QALYs =	33.03
**Tobacco Cessation/Diet**
- CPB ratio =	2.50
- QALYS =	63.50
**Exercise/Diet**
- CPB = 	1.50
- QALYs = 	1.95

## Conclusion

- Woolf indicates his model can use QALYs or CE to replace 30-year mortality, and adjust for intensity of intervention
- 30-year mortality and clinically preventable burden allow broad comparisons across behavior change outcomes and other treatments for disease
- Resulting comparisons are meaningful at policy as well as individual counseling levels