Abstract
BACKGROUND: Health-related quality of life (HRQoL) assessments such as St. George's Respiratory Questionnaire (SGRQ) are often used as outcome measures to evaluate patient-perceived changes in health status among individuals with lung disease. Several factors have been linked to deterioration in SGRQ, including symptoms (dyspnea, wheezing) and exercise intolerance. Whether these findings apply to individuals with alpha-1 antitrypsin deficiency (AATD) remains incompletely studied. This longitudinal study examines the trajectory of SGRQ scores in a cohort of United States individuals with AATD-associated lung disease and defines factors associated with longitudinal change. METHODS: Individuals with AATD-associated lung disease enrolled in AlphaNet, a disease management program, who had ≥3 SGRQ measurements collected between 2009 and 2019, and baseline data for clinically important variables were included in these analyses. Data collected after lung transplants were excluded. Mixed-effects model analyses were used to evaluate the changes in SGRQ total and subscale scores over time and by modified Medical Research Council (mMRC) Scale, use of oxygen, age, sex, productive cough, and exacerbation frequency at baseline. Sensitivity analyses were conducted to examine the potential effect of survivor bias. RESULTS: Participants (n=2456, mean age 57.1±9.9 years, 47% female) had a mean SGRQ total score of 44.7±18.9 at baseline, 48% used oxygen regularly, and 55% had ≥2 exacerbations per year. The median length of follow-up was 6 (IQR 3-9) years. The SGRQ total score and subscales remained stable throughout the observation period. Age, mMRC categories, presence or absence of productive cough, frequency of exacerbations, and use of oxygen at baseline were significantly associated with the rate of change of SGRQ total (p<0.0001). CONCLUSION: We observed long-term stability in HRQoL and an association between the rate of change in SGRQ and baseline mMRC, exacerbation frequency, productive cough, and use of oxygen in this cohort of individuals with AATD-associated lung disease.