In patients with the genetic disorder alpha-1 antitrypsin deficiency (AATD), it is important to take AAT levels into consideration when evaluating any possible alterations in lung function parameters, according to findings from a prospective study published in The Brazilian Journal of Pulmonology.
Individuals with AATD have a predisposition for the development of pulmonary involvement and/or hepatic involvement. In those with lung issues, emphysema is typically reported.
The researchers sought to evaluate whether any type of association exists between AAT levels and pulmonary function parameters, as measured by spirometry. A total of 1510 consecutive individuals who had visited the Hospital Universitario Nuestra Señora de Candelaria in Tenerife, Spain, and had undergone blood work and spirometry, participated in the study. All patients were recruited between January 2011 and June 2015.
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Four prebronchodilator and postbronchodilator spirometric variables were defined:
- Forced vital capacity (FVC) <80 of the predicted value
- Forced expiratory volume in 1 second (FEV1) <80% of the predicted value
- FEV1/FVC ratio <70%
- Forced expiratory flow (FEF) of 25% to 75% (FEF25%-75%) <60%.
The following study inclusion criteria applied:
- Providing written informed consent
- Being able to perform spirometry successfully (ie, 3 acceptable, reproducible maneuvers)
- Undergoing spirometry and establishment of AAT levels per blood nephelometry at the same visit.
The final study sample included a total of 1334 participants, with 176 individuals ultimately not fulfilling study
inclusion criteria.
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The mean participant age was 56.4±18.5 years; patients’ mean body weight was 81.4±18.6 kg. Overall, 770 of the 1334 participants were male. Regarding smoking status, 263 of the participants were active smokers and 494 were former smokers.
The mean AAT level reported was 125.1±31.9 mg/dL. In all, 27.1% (362 of 1334) of the participants exhibited an obstructive pattern on spirometry (ie, FEV1/FVC <70%).
Results of the study revealed a statistically significant association between lung function parameters indicative of airflow obstruction and AAT level of under 40 mg/dL (χ2=22.61; P <.0001; odds ratio, 5.46; 95% CI, 1.36-21.96; P <.05).
Based on these findings, it appears that in individuals with low AAT levels—that is, 0 to 40 mg/dL—altered lung function parameters are observed in airflow obstruction, with this interval corresponding to the most deficient genotypes in those with AATD (Pi*ZZ and some rare variants).
“In conclusion, this study shows that we must take into account AAT levels since, in addition [to] determining whether a patient has AAT deficiency . . . they can guide us to the probability of a patient developing lung function impairment,” the authors highlighted.
Reference
Hernández-Pérez JM, López-Charry CV. Is there any kind of relationship between alpha-1 antitrypsin levels and lung function parameters? J Bras Pneumol. 2023;49(1):e20220432. doi:10.36416/1806-3756/e20220432
