Augmentation therapy for alpha1 antitrypsin deficiency: a meta-analysis.
BACKGROUND
Augmentation with exogenous alpha1-antitrypsin (alpha1-AT) is the only specific therapy for alpha1-AT deficiency. Uncertainty persists concerning its effectiveness.


OBJECTIVE
To test the hypothesis that augmentation therapy in patients with alpha1-AT deficiency slows the decline in FEV1.


METHODS
Randomized and nonrandomized clinical studies with either parallel-group design or single cohort pre-post design were eligible if they compared augmentation therapy with a control regimen and if long-term (> 1 y) longitudinal FEV1 follow-up data were collected.


RESULTS
FEV1 data from five trials with 1509 patients were combined by random effects meta-analysis. The decline in FEV1 was slower by 23% (absolute difference, 13.4 ml/year; CI, 1.5 to 25.3 ml/year) among all patients receiving augmentation therapy. This overall protective effect reflected predominantly the results in the subset of patients with baseline FEV1 30-65% of predicted. In that subset, augmentation was associated with a 26% reduction in rate of FEV1 decline (absolute difference, 17.9 ml/year; CI, 9.6 to 26.1 ml/year). Similar trends amongst patients with baseline FEV1 percent of predicted < 30% or > 65% were not statistically significant.


CONCLUSIONS
This meta-analysis supports the conclusion that augmentation can slow lung function decline in patients with AAT deficiency Patients with moderate obstruction are most likely to benefit.
Chapman
Kenneth R
KR
Asthma & Airway Centre, University Health Network, Toronto Western Hospital, Toronto, Ontario, Canada. kchapman@ca.inter.net
Stockley
Robert A
RA
Dawkins
Clara
C
Wilkes
Mahlon M
MM
Navickis
Roberta J
RJ
D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000209:etiology; D000515:alpha 1-Antitrypsin / Q000627:therapeutic use*; D019896:alpha 1-Antitrypsin Deficiency / Q000150:complications / Q000188:drug therapy*
D000515:alpha 1-Antitrypsin