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Table 9 Sensitivity analysis

From: Triple combination therapy and zeaxanthin for the treatment of neovascular age-related macular degeneration: an interventional comparative study and cost-effectiveness analysis

Model Incremental cost Incremental QALY gain $/QALY
Therapeutic changes in the TTZ cohort
 Base case
  Zx daily for 9 years in the triple therapy with Zx cohort $859 0.162 $5302
  Zx daily for 2 years only in the triple therapy with Zx cohort (−$1318) 0.162 (−$8148)
  Two additional treatments: bevacizumab, PDT and dexamethasone, years 3–9 in both cohorts $859 0.162 $5,312
  Costs in both cohorts are doubled $1718 0.162 $10,623
  Zx cost over 9 years is doubled from $30/month to $60/month $3746 0.162 $23,154
  Zx cost/month for cost-utility ratio of $50,000/QALY $150 0.162 0 $50,000
  Zx cost/month for cost-utility ratio of $100,000/QALY $318 0.162 $100,000
  Zx cost/month for cost-utility ratio of $158,000/QALY(WHO upper limit for cost-effectiveness = 3× GDP per capita) $513 0.162 $158,000
Altering patient value gains associated with TTZ
 Doubling patient value gains in both cohorts $859 0.324 $2,656
 Halving the patient value gain from Zx $859 0.081 $10,623
 Loss of Zx benefit after year 2 with 2 years of Zx therapy in the TTZ cohort (−$1318) 0.036 (−$36,665)
 Loss of Zx benefit after year 2, with 9 years of Zx therapy in the TTZ cohort $859 0.036 $23,892
 Zx incremental QALY gain for $50,000/QALY $859 0.017 $50,000
 Zx incremental QALY gain for $100,000/QALY $859 0.0086 $100,000
 Zx incremental QALY gain required for $158,000/QALY (WHO upper limit for cost-effectiveness = 3× 2015 US GDP per capita) $859 0.0054 $158,000
Integrating the therapeutic QALY gain and costs saved by TTZ decreasing the onset of neovascular AMD in the fellow eye: combined-eye model
 Incremental cost-utility
  Zx daily for 9 years in the TTZ cohort vs. TT cohort—assumes that TTZ yields an absolute risk reduction of CNV in the 2nd eye of 30.3 % (−$2291) 0.362 (−$6332)
 Average cost-utility
  Zx daily for 9 years in the TTZ cohort vs. TT cohort: assumes TTZ reduces the absolute risk reduction of CNV in the 2nd eye by 30.3 % 7249 0.7212 $10,052
  1. A negative cost-utility ratio indicates that neovascular age-related macular degeneration triple therapy with zeaxanthin provides greater patient value than triple therapy without zeaxanthin and is also less expensive than triple therapy without zeaxanthin.) (Dollars are 2015 US real dollars discounted at 3 % annually. QALYs are discounted at 3 % annually.
  2. Incremental cost–utility of TTZ vs. TT cohorts, combined-eye model
  3. QALY quality-adjusted life-year, $/QALY dollars expended per QALY gained, PDT photodynamic therapy with verteporfin, GDP gross domestic product, TTZ triple combination therapy with zeaxanthin, TT triple combination therapy, Zx zeaxanthin, WHO World Health Organization