Table 1.

Summary of studies evaluating AAT augmentation in severe antitrypsin deficiency

Study	Comparisons	Results treated by AAT augmentation versus untreated	Evidence level
Seersholm et al40	FEV1 decline in German patients treated with AAT and Danish untreated patients	FEV1 decline in treated Germans was 56 mL/year, less than the 75 mL/year in Danes (P = 0.02)	C
Alpha-1-antitrypsin deficiency registry study group41	Nonrandomized comparison of patients receiving AAT augmentation with untreated patients	Decreased mortality (risk ratio 0.64), (P = 0.02) in patients with FEV1 35%–49% predicted decline in FEV1 was less with augmentation: 66 versus 93 mL/year, (P = 0.03)	C
Dirksen et al43	Randomized placebo controlled trial in 56 patients over 3 years	CT scan progression of emphysema less in treated patients, (P = 0.07); no difference in FEV1	B
Wencker et al44	Retrospective comparison of decline in FEV1 before and after treatment	Decline in FEV1 34 mL/year less after therapy than the 49 mL/year before therapy (P = 0.019)	C
Chapman et al45	Meta-analysis of the above studies and patients on AAT treatment with matched controls from the Canadian AAT registry (total n = 1509)	Positive effect of AAT augmentation with reduction in FEV1 decline by 26% (17.9 mL/year). Effect due to subjects with FEV1 30%–65% of predicted	C
Dirksen et al46	Randomized weekly AAT augmentation versus placebo for 2.0–2.5 years (total n = 77)	Trend suggestive of reduction in progression of emphysema by CT densitometry (P = 0.049–0.084)	B
Gotzsche and Johansen47	Cochrane meta-analysis of Dirksen’s two placebo controlled randomized trials	Lung density deteriorated less in treated group (P = 0.03)	B
Stockley et al48	Integrated analysis of Dirksen’s two placebo controlled randomized trials	Yearly loss in lung density in treated group significantly less than placebo 1.73 g/L versus 2.74 g/L, (P = 0.006)	B

Abbreviations: AAT, α₁-antitrypsin; CT, computerized tomography; FEV₁, forced expiratory volume in one second.