The Clinical Profile of Subjects Included in the Swedish National Register on Individuals with Severe Alpha 1-Antitrypsin deficiency

Abstract

The Swedish national register of severe alpha1-antitrypsin (AAT) deficiency was established in 1991. The main aims are to prospectively study the natural history of severe AAT deficiency, and to improve the knowledge of AAT deficiency. The inclusion criteria in the register are age ≥18 years, and the PiZ phenotype diagnosed by isoelectric focusing. The register is kept updated by means of repeated questionnaires providing data to allow analysis of the mode of identification, lung and liver function, smoking-habits, respiratory symptoms and diagnoses as reported by physicians.

Until February 2014, a total of 1553 PiZZ individuals had been included in the register. The 1102 subjects still alive constituted about 20% of the adult PiZZ individuals in Sweden. Forty-three percent of the subjects had been identified during investigation of respiratory symptoms, 7% by an investigation of liver disease, 26% in an investigation of other pathological conditions, and 24% in a population or family screening. Forty five percent of the subjects had never smoked, 47% were ex-smokers, and 8% current smokers. Twenty-eight percent of the never-smokers, 72% of the ex-smokers, and 61% of the current smokers fulfilled the criteria for COPD with a FEV₁/FVC ratio of <0.70.

Among the 451 deceased, the most common cause of death was respiratory diseases (55%), followed by liver diseases (13%). We conclude that the detection rate of severe AAT deficiency is relatively high in Sweden. Large numbers of subjects are identified for other reasons than respiratory symptoms, and the majority of these have never smoked.

Keywords:

• alpha 1-antitrypsin deficiency
• lung function
• smoking
• national register

Acknowledgments

The authors gratefully acknowledge the expert secretarial assistance provided by Isabella Björk, and the reporting of patient data to the national AAT deficiency register undertaken by all Swedish physicians.

Funding

This work was supported by grants from The Swedish Heart-Lung Foundation and The Swedish Society of Medicine.

Declaration of Interest Statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.