Table 3
Comparison of cost effectiveness studies of augmentation therapy for AAT deficiency
| Study | Natural history | Augmentation cost/year (US$) | Utility weight | Method of calculation | Outcome indices | Major conclusions | Sensitivity analysis |
|---|---|---|---|---|---|---|---|
| Utility weight adjusts measure of quality based on impact of disease and ranges from 0 (health state equivalent to death) to 1 (perfect health). | |||||||
| DEALE = declining exponential approximation of life expectancy: life expectancy is inverse of mortality at 1 year (mortality = −(1/t) × ln (survival at time t)); CLYS = cost per life-year saved; ICLYS = incremental cost per life-year saved; QALY = quality adjusted life-year; ICER = incremental cost effectiveness ratio (US$ per QALY). | |||||||
| Hayet al21 | Larrson23 | 30 000 (1990 $) | Arbitrary: 0.75 | Life expectancy: natural history data Outcome efficacy: hypothetical (0–100%) | CLYS | At 30% efficacy the CLYS would be $50 000–128 000 and comparable to other medical interventions | Outcomes most sensitive to efficacy and treatment cost assumptions |
| Alkinset al.19 | NHLBI Registry7 | 51 948 (1998 $) | Not included: 1 | Life expectancy: DEALE Outcome efficacy: 55% (based on Registry data) | ICLYS: at 55% efficacy the ICLYS for subjects with FEV1 <50% would be $13 971 | Outcomes most sensitive to efficacy and, to a lesser degree, treatment cost assumption | |
| Gildeaet al20 | NHLBI Registry7 | 54 765 (2001 $) | Expert opinion based on COPD stage:Stage I: 0.93 Stage II: 0.75 Stage III: 0.26 | Markov analytical model validated using NHLBI Registry data | QALY, ICER | ICER for lifetime treatment per QALY gained is $312 511 | No assumption decreased ICER to less than $100 000 unless augmentation cost reduced to $14 000 |
