2Prevention Can be classified into three types: Primary Secondary Tertiary
3Primary PreventionRemoving the causeSanitationPassive smoking
4Secondary PreventionIdentify presymptomatic disease before damage is doneExamples?Blood pressureDiabetic screening
5Tertiary PreventionLimiting complications and disability in established disease by regular surveillanceExamples?Diabetic Retinopathy Screening
6Methods of Screening Case Finding True screening opportunistic or anticipatoryTrue screeningWhat are the pros and cons of each?
7Wilson’s Criteria Condition must be: Screening must be: common importantdiagnosablehave a latent intervalScreening must be:cheap and simplecontinuoustargeted towards a high risk group
8Wilson’s CriteriaAlthough the following were not part of Wilson’s original criteria we might add:Disease readily treatableTests sensitive, specific, safe, acceptable and easy to interpretBenefits outweigh costs
9The Test Explain the following terms: Sensitivity Specificity few false negativesSpecificityfew false positivesPositive Predictive Valuelikely to be correct when positive
10The Test Discuss the trade off between sensitivity and specificity What happens if the prevalence is low?even test of high sensitivity and specificity have a low predictive valueDo we move the point of death?Imperfect knowledge of natural history of the condition causes what problems?
11Benefits of Screening Improved mortality Improved morbidity Possible savings on costs of future treatment
12Costs of Screening Patients: Doctors NHS anxiety false reassurance economicDoctorsNHS
13Obstacles to Prevention Discuss the obstacles to prevention from:patientsdoctorsNHS
14Overcoming Patient Obstacles Point out debitsPoint out benefitsAnticipate and discuss difficultiesSuggest coping stategiesSimple advice and written information