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Decline in pulmonary function in patients with alpha 1-antitrypsin deficiency
T Evald1, A Dirksen, S Keittelmann
1Department of Pulmonary Medicine P, Bispebjerg Hospital, Copenhagen, Denmark.
Insights
Individuals with severe alpha-1-antitrypsin (AAT) deficiency experience lung function decline. Smokers and non-smokers are at risk for pulmonary emphysema, with disease onset potentially later in non-smokers.
Area of Science:
- Pulmonology
- Genetics
- Internal Medicine
Background:
- Alpha-1-antitrypsin (AAT) deficiency (phenotype PiZ) is a genetic disorder predisposing individuals to severe lung disease.
- Pulmonary emphysema is a significant complication, necessitating understanding of disease progression in affected individuals.
Purpose of the Study:
- To investigate the annual decline in pulmonary function in patients with severe AAT deficiency.
- To assess the influence of smoking status on the rate of lung function decline and disease onset.
Main Methods:
- Longitudinal follow-up of 65 patients with severe AAT deficiency (PiZ phenotype) over a median of four years.
- Regular spirometry measurements, with pulmonary function data adjusted for sex, age, and height.
- Analysis of FEV1 decline rates in relation to smoking status (smokers, ex-smokers, never-smokers).
Main Results:
- The median annual decline in FEV1 was 1.9% predicted/year, largely independent of age and initial pulmonary function.
- While not statistically significant, ex-smokers and smokers showed a tendency towards faster FEV1 decline (1.7% and 3.8% predicted/year) compared to never-smokers (3.7% predicted/year).
- Smokers and ex-smokers presented with lower FEV1 at diagnosis and were younger than never-smokers.
Conclusions:
- Both smokers and non-smokers with severe AAT deficiency are at risk of developing pulmonary emphysema.
- The progression rate of emphysema appears similar regardless of smoking status, but disease onset may be delayed in non-smokers.
Abstract:
Sixty-five patients with severe alpha 1-antitrypsin (AAT) deficiency (phenotype PiZ) were followed with spirometry at regular intervals of one year and a median observation period of four years. The annual decline in pulmonary function was adjusted for sex, age and height by division with the predicted normal pulmonary function. The median decline in FEV1 was 1.9% predicted/year. The rate of decline was independent of age and pulmonary function, except for patients with FEV1 below 25% of predicted normal. There was a tendency towards a slower median decline in FEV1 in ex-smokers (1.7% predicted/year) compared to smokers (3.8% predicted/year) and never-smokers (3.7% predicted/year), however, this difference was not significant (p greater than 0.01). At the time of diagnosis smokers and ex-smokers had a lower FEV1 (44 and 38% predicted) than never-smokers (85% predicted) (p less than 0.02), and smokers and ex-smokers were generally younger (median age 44 and 42 years, respectively) than never smokers (median age 55 years) (p greater than 0.1). Our data indicate that smokers as well as nonsmokers with severe AAT deficiency are at risk of developing pulmonary emphysema. The disease seems to appear later in nonsmokers, though once initiated it progresses at the same rate.