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Table 7 Total knee replacement economic results

From: Local anaesthetic wound infiltration in addition to standard anaesthetic regimen in total hip and knee replacement: long-term cost-effectiveness analyses alongside the APEX randomised controlled trials

  Difference (intervention – control) a
  N Mean (95 % CI) P value
MAIN ANALYSIS: NHS and personal social services (PSS) perspective     
Mean QALY gain 316 0.009 (−0.030 to 0.049) 0.64
Mean NHS+PSS Cost difference 316 –£77 (£–451 to £296) 0.68
Incremental net monetary benefit – lambda £10,000 316 £171 (£–452 to £793) 0.59
Incremental net monetary benefit – lambda £20,000 316 £264 (£–710 to £1,238) 0.60
Incremental net monetary benefit – lambda £30,000 316 £357 (£–992 to £1,707) 0.60
SECONDARY ANALYSIS: NHS perspective only     
Mean QALY gain 316 0.009 (−0.030 to 0.049) 0.64
Mean NHS cost difference 316 –£74 (£–414 to £266) 0.67
Incremental net monetary benefit – lambda £20,000 316 260 (£–690 to £1,210) 0.59
SENSITIVITY ANALYSIS: using macro-costed prescribed medications     
Prescribed medications b 316 –£14 (£–21 to £ –6)  
Mean QALY gain 316 0.009 (−0.030 to 0.049) 0.64
Mean NHS+PSS cost difference 316 –£121 (£–491 to £249) 0.52
Incremental net monetary benefit – lambda £20,000 316 £308 (£–665 to £1,281) 0.53
SENSITIVITY ANALYSIS: 50 % higher local inpatient costs     
Initial inpatient stay b 316 –£258 (£164 to £353)  
Mean QALY gain 316 0.008 (−0.032 to 0.047) 0.70
Mean NHS+PSS cost difference 316 –£2 (£–483 to £478) 0.99
Incremental net monetary benefit – lambda £20,000 316 £159 (£–882 to £1,200) 0.76
SENSITIVITY ANALYSIS: 50 % lower local inpatient costs     
Initial inpatient stay b 316 £84 (£–66 to £234)  
Mean QALY gain 316 0.006 (−0.034 to 0.045) 0.79
Mean NHS+PSS cost difference 316 –£143 (£–423 to £137) 0.32
Incremental net monetary benefit – lambda £20,000 316 £253 (£–674 to £1,180) 0.59
  1. a All results are adjusted for minimisation variables, and baseline utility for QALYs, M=20 multiple imputation sets, bootstrapped confidence intervals with 1000 replications, except results noted with b
  2. b Unadjusted estimates with imputed data using M=20 multiple imputation sets