Background: Alpha-1-antitrypsin deficiency (AATD) is a rare hereditary disease that is associated with a higher risk to develop chronic obstructive pulmonary disease and liver cirrhosis. Previous cross-sectional studies on AATD individuals have shown a relationship between worse St George's Respiratory Questionnaire (SGRQ) scores and elevated exacerbation rate or high cigarette consumption. There is a lack of longitudinal data on the relationship between the exacerbation rate and worsening of SGRQ during disease. The aim of this study was to provide not only cross-sectional data but also information about the deterioration in quality of life over a follow-up period up to 7 years (median follow-up period of 3.33 years).
Methods: We investigated questionnaire-based data of the German AATD registry concerning the relationship between SGRQ and exacerbation frequency, smoking history, forced expiratory volume in 1 second (FEV1) and carbon monoxide diffusion capacity (DLCO) first in cross-sectional analysis and later in longitudinal analysis.
Results: Eight hundred sixty-eight individuals with protease inhibitor ZZ (PiZZ) genotype with an average age of 52.6±12.8 years had an SGRQ score of 45.7±20.6. SGRQ significantly correlated with the exacerbation frequency within the last 2 years (r=0.464; P<0.001), smoking history (r=0.233; P<0.001), FEV1 (r=-0.436; P<0.001), DLCO (r=-0.333; P<0.001), and patients' age (r=0.292; P<0.001). Individuals with occupational dust exposure had significantly worse quality of life (P<0.001). Mean annual deterioration of SGRQ in all patients with available follow-up data (n=286) was 1.21±4.45 points per year. Univariate and multivariate analysis showed a significant relationship between worsening of SGRQ/year and exacerbation frequency in the follow-up period (r=0.144; P=0.015).
Conclusion: Worsening of SGRQ is associated with the exacerbation frequency in individuals with PiZZ AATD.
Keywords: AATD; COPD; FEV1; SGRQ; alpha-1-antitrypsin deficiency; emphysema; exacerbations; quality of life.