1. Diagnostics outside the laboratory
NPEx road show, 21 November 2016
Dr Michael Power
Evidence-based practice lead, NuTH Deputy Director NIHR Diagnostic Evidence Co-operative (DEC), Newcastle

2. How to add value with diagnostics?
Diagnostics outside the service laboratory Ethos of evidence-based practice + Remit of NIHR DEC
High value testing 

3. How to measure value of a healthcare service?
Clinical value = clinical outcomes for cost of service Outcomes = net benefits Net benefits = total benefits – total harms Cost = net cost Net cost = total cost – total income Value of a change = improvement in outcomes ÷ change in costs ICER = incremental cost-effectiveness ratio = 1 / Value
Economists see the world upside down
nwod edispu

4. How to add value to healthcare services?
Value “doing the thing”
Add value by “doing the thing right”
Add value by “doing the right thing right”
E.g. NPEx + EBM
High value
High value
E.g. NPEx
High value
Poor value
Efficiency gain
Efficiency gain
Poor value
Poor value
Effective-ness gain
Hat tip to Sir Muir Gray: Better value healthcare

5. How to value testing?
Key question
Evaluation methods
How accurate is the test? How useful is the test to patients? Would investing in it provide value for money, and be affordable?
Diagnostic accuracy Clinical utility Health economics studies

6. How to measure test accuracy?
Laboratory-important measures
Patient- and clinician-important measures
Sensitivity Specificity
Predictive values of a result “Collateral damage”: false positive results false negative results
Useful when comparing results from different studies because prevalence has no effect
Can be used with case-control studies
Needed by patients and clinicians for decision-making
Must not be used with case-control studies
Must not be used without stating prevance

7. Clinical accuracy of a test

8. Clinical accuracy of a test

9. Clinical accuracy of a test

10. How to measure clinical utility?
Patient- and clinician-important chances
Patient- and clinician-important outcomes
Predictive values of a result “Collateral damage”: false positive results false negative results
Benefits Harms
Expected utility = probability of the outcome × outcome
Net expected utility = sum(expected utilities of good and bad outcomes)

11. How to measure clinical utility?
Decision threshold
Informal calculation: expected benefits outweigh expected harms and costs
Formal calculation: health economics
See

12. How to measure cost-effectiveness?
Laboratory-important measures
Patient- and clinician-important measures
Sensitivity Specificity
Predictive values of a result “Collateral damage”: false positive results false negative results
Useful when comparing results from different studies because prevalence has no effect
Can be used with case-control studies
Needed by patients and clinicians for decision-making
Must not be used with case-control studies
Must not be used without stating prevance

13. How to measure cost-effectiveness?
Value = outcomes for cost Outcomes = net benefits Net benefits = total benefits – total harms Cost = net cost Net cost = total cost – total income Value = improvement in outcomes ÷ change in costs ICER = incremental cost-effectiveness ratio = 1 / Value
Economists see the world upside down
nwod edispu
Value for money
Affordability

14. Adding value with diagnostics
Add value by “doing the right thing right”
Clinical accuracy PPV and NPV given prevalence
Clinical utility PPV and NPV cf decision threshold
High value
Efficiency gain
Effective-ness gain

15. Questions and discussion