Liver Disease and Prevalence of Liver Transplantation in Adults With ZZ Alpha-1 Antitrypsin Deficiency—A Meta-Analysis

Alpha-1 antitrypsin deficiency (A1ATD) is an inherited metabolic disorder caused by a mutation (ZZ) in the SERPINA1 gene. Carriers are predisposed to liver and lung pathology. The severity of A1ATD-associated liver disease is highly variable, necessitating further characterisation. This study aims to investigate the risk and extent of liver disease and the prevalence of liver transplantation in ZZ A1ATD patients. Several established databases, including Ovid, EBSCO, PubMed, and Cochrane Library, were searched from inception to May 12, 2024. Data were pooled using a random effects model, and study weight was calculated using the inverse variance method. Crude odds ratios (cOR) were calculated using participants with the MM genotype as the comparator. The study was registered in PROSPERO (CRD42022335666). Of the 4420 studies identified, 45 studies and 8638 A1ATD patients (38.8% female) were included. ZZ A1ATD patients demonstrate an increased risk of liver diseases compared to controls, including steatosis (crude odds ratio (cOR): 1.52 [95% CI: 1.21, 1.91]), fibrosis (cOR: 9.85 [95% CI: 5.70, 17.03]), cirrhosis (cOR: 10.43 [95% CI: 5.51, 19.73]), and liver cancers (cOR: 14.12 [95% CI: 6.50, 30.66]). The prevalence of liver transplantation is considerable, with rates reaching 5% [95% CI: 0.00, 12.34]. Our findings confirm the substantial burden of liver disease in ZZ A1ATD patients, including subclinical manifestations such as steatosis and fibrosis that may remain undetected. Given the lack of approved treatments for A1ATD-associated liver disease, prioritising the development of novel therapies to stop or reverse liver disease is essential.