Table 4. Potential benefits of alpha-1 antitrypsin augmentation therapy (AAT-AT).
| Clinical feature |
Effect of AAT-AT versus non-treated patients | Evidence type/average follow-up |
|---|---|---|
| CT density | Slower rate of emphysema progression (0.79 g/L/year [95% CI 0.29–1.29; P = 0.002]) |
Meta-analysis56 (until 2017) |
| Decreased rate in emphysema progression (0.74 g/L/year [95% CI 0.06–1.42; P = 0.03]) |
RCT74 (4.6-year approximately) |
|
| Reduction in decline rate of emphysema (–1.26 g/L/year [standard error 0.29; P = 0.001]) |
Open label extension75 (4.6-year approximately) |
|
| Smaller change in lung density in treated group (–4.08 g/L treated versus –6.38 non-treated) Reduction in lung density (2.30 [95% CI 0.67–3.93; P = 0.006]) in 2.5 years |
Combined studies70 (2.5-year) |
|
| Lung function | FEV1% predicted: 0.56% predicted/year (95% CI 1.14–0.29; P = 0.20) | Meta-analysis56 (until 2017) |
| FEV1% predicted: 47.4 ± 12.1% treated versus 47.2 ± 11.1% non-treated | RCT74 (4.6-year) |
|
| FEV1: 1.25 L treated versus 1.19 L non-treated (P <0.05) | Observational, retrospective69 (3-year) |
|
| FEV1% predicted: 37 ± 18% treated versus 74 ± 35% non-treated | Re-analysis AATD registry group data76 (8-year) |
|
| FEV1% predicted: 48 ± 16.4% treated versus 47.9 ± 18.6% non-treated | Combined studies70 (2.5-year) |
|
| Improvement in DLCO (0.11 [–0.33–0.11; P = 0.34]) | Meta-analysis56 (until 2017) |
|
| Improvement in DLCO (58.9 ± 26.3 treated and 69.1 ± 69.2 non-treated) | Observational, retrospective69 (3-year) |
|
| Exacerbations | 0.29/year (0.02–0.54; P = 0.02) exacerbations; small but significant increase in annual exacerbation rate on treatment group |
Meta-analysis56 (until 2017) |
| Increased risk of exacerbation in non-treated patients (1.4- to 4.2-fold; P <0.05) |
Observational, retrospective69 (3-year) |
|
| Health status | Increased deterioration in SGRQ on placebo (0.83 [–3.55–1.89; P = 0.55]) | Meta-analysis56 (until 2017) |
| Mortality | Improved survival on treatment group | Re-analysis AATD registry group data76 (8-year) |
alpha-1 antitrypsin deficiency, AATD; CI, confidence interval; computed tomography, CT; DLCO, diffusing capacity of lung for carbon monoxide; FEV1, forced expiratory volume in 1 second; RCT, randomized controlled trial; SGRQ, Saint George’s Respiratory Questionnaire.