1. Funding: Health Foundation, ESVS Economic evaluation alongside clinical trials: The GALA trial Manuel Gomes, Marta Soares, Jo Dumville, David Torgerson Dep. of Health Sciences - University of York

2. Funding: Health Foundation, ESVS Why is economic evaluation important? The objective of the budget holder is to maximise health gains from a fixed budget There is an opportunity cost associated with each choice Economic evaluation aims to inform decisions about resource allocation - value for money

3. Funding: Health Foundation, ESVS What is economic evaluation? Comparative analysis of competing interventions with respect to: costs health benefits Characterisation of uncertainty surrounding the decision Identify and make explicit the set of criteria used for decision making

4. Funding: Health Foundation, ESVS Main methods for economic evaluation Cost-effectiveness analysis Health benefits measured in natural units: event-free days Cost-utility analysis Health benefits expressed as a single measure combining quality gains (morbidity) and quantity gains (longevity) Quality Adjusted Life Years (QALYs)

5. Funding: Health Foundation, ESVS Economic evaluation potential results Differences in cost Differences in effectiveness +- - + New intervention is - more costly - less beneficial New intervention is - less costly - more beneficial New intervention is - less costly - less beneficial New intervention is - more costly - more beneficial NE quadrant NW quadrant SE quadrant SW quadrant + 0

6. Funding: Health Foundation, ESVS The GALA Trial Preliminary Economic Analysis Cost effectiveness analysis RCT based Perspective – health care provider Time horizon – 1 year Health outcome Event free survival (MI, stroke, death) Relevant resources

7. Funding: Health Foundation, ESVS The GALA Trial Unit Costs ResourceUnitUnit cost (£)Source WardDay170CIPFA Hospital ‘hotel’ costs Intensive therapy Unithour1328/24Dept Health High dependency Unithour584/24Dept Health Traineeminute0.7PSSRU Consultantminute4.5PSSRU Theatre & recovery room Nurse Sisterminute.68PSSRU Theatre Nurseminute.88PSSRU Overheadsminute2.39Sculpher et al. LA anaestheticsSurgery6.5BNF Consumables & drugs GA anaestheticsSurgery22.5BNF ShuntsUnit65Manufacturer PatchesUnit40Manufacturer Complications costs StrokeHRG1637Dep Health MIHRG1024Dep health

8. Funding: Health Foundation, ESVS The GALA Trial Resource Use Resource GA Endarterectomy (n=1753) LA Endarterectomy (n=1773) Hospital stay (days) (n=1737) (n=1756) Mean (SD)6 (7)6.2 (14) Time of surgery (minutes)(n=1711)(n=1717) Mean (SD)93 (33.5)93.2 (36) Post-surgery stay n (missing)1572 (165)1567 (189) Recovery room (hours)(n=1096)(n=1081) Mean (SD)6.4 (17.6) 5.5 (12.1) ITU (hours)(n=377)(n=340) Mean (SD)27.8 (71.4)23.9 (20.9) HDU (hours)(n=529)(n=542) Mean (SD)24.9 (19.6)23.7 (15.4) Surgery related resource use Trainee surgeon n (%)(242) 14(210) 12 Trainee anaesthetist n (%)(246) 16(213) 14 Shunts n (%)(738) 43(248) 14 Patches n (%)(861) 50(728) 42 Post-surgery adverse events Post-surgery stroke n (%)(68) 3.9(63) 3.6 Post-surgery MI n (%)(4) 0.2(9) 0.5

9. Funding: Health Foundation, ESVS The GALA Trial Preliminary Cost Estimation GA Endarterectomy (n=1753) LA Endarterectomy (n=1773) Mean (SD)Median (IQR)Mean (SD)Median (IQR) Theatre costs1277.3 (465)1229 (956-1570)1278.6 (499)1229 (928-1542) Acute care costs568.1 (2085)73 (1.2-585)482.8 (819)53 (1.2-585) Hospital ‘hotel’ costs896.9 (1201)652 (416-999)956.6 (2531)627 (334-978) Consumables & drugs82.1 (74)64 (0-179)43.8 (55)0 (0-64) Costs of adverse events65.3 (311)0 (0-0)66.9 (310)0 (0-0) Total costs2878 (2685)2470 (1891-3170)2821 (2810)2319 (1822-3113) Differential mean cost* (95% CI) ϯ - 59 (-180 to 93) Differential mean event free survival (95% CI) 2.29 (-9.7 to 11.2) * LA minus GA Ϯ Standard t-tests

10. Funding: Health Foundation, ESVS The GALA Trial Ellipse Curves