Slide 12. When Prevention?
- Screening Tests/Circumstances that must exist for screening tests to be useful:
- Condition has significant impact on the individual and society.
- Effective treatment in asymptomatic phase.
- Asymptomatic period for detection and treatment.
- Acceptable screening tests at reasonable costs.
- Disease burden justifies cost.
The clinician and patient should share in decision-making.
Putting prevention into practice (PPP) pg xxii Unfortunately, for most of medial practice, there is insufficient evidence that a service is or is not effective in improving process or outcome measures. Therefore, decision-makers at the policy and at the clinical level often need to consider factors other than scientific evidence in determining whether to offer a preventive service. Particularly for asymptomatic patients, thresholds for performing preventive services differ depending on their potential for harm in the absence of strong evidence of benefit. Frame and Carlson (1975) summarized the circumstances that must exist for screening tests to be useful:
- Condition has significant impact on the individual and society Illness or injury with significant morbidity or mortality or substantial cost to society provide incentives to reduce the frequency or severity of the illness.
- Effective treatment in asymptomatic phase
- The intent of screening tests is to identify a condition prior to the individual experiencing signs or symptoms. Treatment (medical or surgical) must be available to avert the disease (secondary prevention).
- Primary prevention should be the goal for preventive medicine. Identifying hypertension or hypercholesterolemia and following with appropriate treatment will delay or possibly prevent CVA or CHD.
- Asymptomatic period for detection and treatment
- For a screening test to be useful there must be a period between exposure and development of a disease or slow progression of disease (prostate cancer).
- Acceptable screening tests at reasonable costs
- Noninvasive testing is important to the patient.
- Disease burden justifies cost
- Incidence and prevalence are important factors in disease burden. If only a few people can be expect to be affected the cost may be prohibitive.
- A condition with low incidence may justify the cost of screening tests due to the high morbidity and mortality rate for that illness.