Exacerbations, health status and sibling pair comparisons in severe Alpha-1-Antitrypsin Deficiency

Abstract

Alpha-1-Antitrypsin Deficiency (AATD) is a risk factor for the development of early-onset emphysema and airflow obstruction. The current work defines exacerbations, lung function and health status in these patients including sibling pairs. Exacerbations occur commonly in AATD and are associated with worse health status. Exacerbations were associated with a decline in the gas transfer of the lung over time, but show no relationship to changes in forced expiratory volume in one second (FEV1). However, despite lung function decline, patients do not show a progressive loss in health status. Index patients have worse lung function and health status and more emphysema than non-index siblings. These differences are not solely explained by smoking or ascertainment. Although FEV1 values differ between sibling pairs, gas transfer does show significant correlation. Thus disease phenotype may also be influenced by other genetic modifiers. These results provide a firm basis upon which to design, power and implement trials of interventions that may reduce exacerbations and improve health status in patients. Furthermore sibling pairs, particularly those with discordant disease or concordant parenchymal disease, are an ideal group to further investigate the contribution of other genes in the development of COPD or its phenotype in AATD patients.