Asthma in elderly is characterized by increased sputum neutrophils, lower airway caliber variability and air trapping

Abstract

Background: Elderly asthmatics represent an important group that is often excluded from clinical studies. In this study we wanted to present characteristics of asthmatics older than 70 years old as compared to younger patients.

Methods: We conducted a retrospective analysis on a series of 758 asthmatics subdivided in three groups: lower than 40, between 40 and 70 and older than 70. All the patients who had a successful sputum induction were included in the study.

Results: Older patients had a higher Body Mass Index, had less active smokers and were more often treated with Long Acting anti-Muscarinic Agents. We found a significant increase in sputum neutrophil counts with ageing. There was no significant difference in blood inflammatory cell counts whatever the age group. Forced expiratory volume in one second (FEV₁) and FEV₁/FVC values were significantly lower in elderly who had lower bronchial hyperresponsiveness and signs of air trapping. We found a lower occurrence of the allergic component in advanced ages. Asthmatics older than 70 years old had later onset of the disease and a significant longer disease duration.

Conclusion: Our study highlights that asthmatics older than 70 years old have higher bronchial neutrophilic inflammation, a poorer lung function, signs of air trapping and lower airway variability. The role of immunosenescence inducing chronic low-grade inflammation in this asthma subtype remains to be elucidated.

Keywords: Aging; Air trapping; Airway caliber; Asthma; Eosinophils; Hyperresponsiveness; Neutrophils; Sputum.

Fig. 1

FEV1% predicted value in asthmatics classified according to age. Patients younger than 40 years old (group 1), aged between 40 and 70 (group 2) or older than 70 years old (group 3). Group 1 different from group 2 (p < 0.05) and from group 3 (p < 0.001). Group 2 different from group 3 (p < 0.05)

Fig. 2

Residual volume on total lung capacity ratio according to age group. Patients younger than 40 years old (group 1), aged between 40 and 70 (group 2) or older than 70 years old (group 3). Group 1 different from group 2 (p < 0.00001) and from group 3 (p < 0.00001). Group 2 different from group 3 (p < 0.00001)

Fig. 3

Correlations between FEV₁ (a) and FEV₁/FVC (b) and RV/TLC