Combined obstructive airflow limitation associated with interstitial lung diseases (O-ILD): the bad phenotype ?

Abstract

Background Patients suffering from combined obstructive and interstitial lung disease (O-ILD) represent a pathological entity which still has to be well clinically described. The aim of this descriptive and explorative study was to describe the phenotype and functional characteristics of a cohort of patients suffering from functional obstruction in a population of ILD patients in order to raise the need of dedicated prospective observational studies and the evaluation of the impact of anti-fibrotic therapies. Methods The current authors conducted a retrospective study including 557 ILD patients, with either obstructive (O-ILD, n = 82) or non-obstructive (non O-ILD, n = 475) pattern. Patients included were mainly males (54%) with a mean age of 62 years. Results Patients with O-ILD exhibited a characteristic functional profile with reduced percent predicted forced expired volume in 1 s (FEV1) [65% (53–77) vs 83% (71–96), p < 0.00001], small airway involvement assessed by maximum expiratory flow (MEF) 25/75 [29% (20–41) vs 81% (64–108), p < 0.00001], reduced sGaw [60% (42–75) vs 87% (59–119), p < 0.01] and sub-normal functional residual capacity (FRC) [113% (93–134) vs 92% (75–109), p < 0.00001] with no impaired of carbon monoxide diffusing capacity of the lung (DLCO) compared to those without obstruction. Total lung capacity (TLC) was increased in O-ILD patients [93% (82–107) vs 79% (69–91), p < 0.00001]. Of interest, DLCO sharply dropped in O-ILD patients over a 5-year follow-up. We did not identify a significant increase in mortality in patients with O-ILD. Interestingly, the global mortality was increased in the specific sub-group of patients with O-ILD and no progressive fibrosing ILD phenotype and in those with connective tissue disease associated ILD especially in case of rheumatoid arthritis. Conclusions The authors individualized a specific functional-based pattern of ILD patients with obstructive lung disease, who are at risk of increased mortality and rapid DLCO decline over time. As classically those patients are excluded from clinical trials, a dedicated prospective study would be of interest in order to define more precisely treatment response of those patients.

Small airway dysfunction in idiopathic pulmonary fibrosis

“…Among the 84 patients diagnosed with SAD, only 11 cases (11/84, 13%) had signi cant obstructive ventilatory dysfunction (FEV1/FVC < 0.7), which was slightly higher than the value of 7% (5/68) reported by Julien Guiotd [10]. In contrast, the majority of patients (87%) showed no signi cant obstructive ventilatory dysfunction by routine PFT.…”

“…Few clinical studies have focused on ILD with small airway lesions. Julien Guiotd et al [10] have reported that about 15% of ILD patients are complicated with obstructive ventilator dysfunction. Among them, 7% (5/68) of patients have IPF comorbid obstructive ventilator dysfunction and impaired small airway function.…”

“…Stijn Everleden et al [9] have compared pathological lung tissues of end-stage IPF patients undergoing lung transplantation with healthy donors without lung disease and found that the loss of terminal bronchioles is signi cant in IPF patients' lung tissues. Julien Guiotd and colleagues [10] have recently reported that about 15% of ILD patients have combined obstructive ventilator dysfunction, 7% (5/68) of IPF patients have obstructive ventilator dysfunction (O-IPF), and their small airway function is impaired signi cantly. A review of the genetics of IPF by Evans et al [11] has concluded that IPF is a complex genetic disorder with abnormal mucus cilia function, and the MUC5B promoter mutation rs35705950 is the most common risk factor for the development of IPF.…”

Small airway dysfunction in idiopathic pulmonary fibrosis

“…Among the 84 patients diagnosed with SAD, only 11 cases (11/84, 13%) had significant obstructive ventilatory dysfunction (FEV1/FVC < 0.7), which was slightly higher than the value of 7% (5/68) reported by Guiot et al (2022). In contrast, the majority of patients (87%) showed no significant obstructive ventilatory dysfunction by routine PFT.…”

“…Few clinical studies have focused on ILD with small airway lesions. Guiot et al (2022) have reported that about 15% of ILD patients are complicated with obstructive ventilator dysfunction. Among them, 7% (5/68) of patients have IPF comorbid obstructive Frontiers in Pharmacology frontiersin.org ventilator dysfunction and impaired small airway function.…”