Are Volatile Organic Compounds Able to Identify Airflow Decline in Asthma?

Figures & data

Table 1 Demographic, Clinical and Inflammatory Characteristics at Baseline of Asthmatics with VOC Measurements (n=45)

Characteristics	No Decline	Airflow Decline	p-value
N (%)	25 (56)	20 (44)
Women (%)	13 (65)	15 (60)	0.767
Age (years)	48 ± 13	53 ± 14	0.2380
BMI (kg/m^2)	25 ± 3	26 ± 4	0.6842
Atopy (Y) (%)	10 (53)	12 (50)	0.999
Smoking status (%)
Never smokers	9 (45)	12 (52)	0.483
Current smokers	6 (30)	3 (13)
Ex-smokers	5 (25)	8 (35)
Age of onset (years)	37 ± 15	38 ± 22	0.9296
Disease duration (years)	11 ± 16	17 ± 14	0.2150
Post-BD FEV1 (L)	2.65 ± 0.98	2.38 ± 0.72	0.2830
Post-BD FEV1/FVC (% pred)	74 ± 11	67 ± 12	0.0494
Reversibility (%)	4.32 ± 6.29	7.48 ± 7.93	0.1601
ACT score	13 ± 5.5	16.7 ± 5.2	0.0455
ACQ score	2.5 ± 1.4	2.0 ± 1.1	0.2343
AQLQ score	4.1 ± 1.5	4.4 ± 1.4	0.3979
FeNO (ppb)	39 (16–71)	29 (19–45)	0.6473
Sputum eosinophil count (% of non-squamous cells)	4.3 (0.1–50.7)	3.4 (0.8–5.4)	0.4155
Sputum neutrophils count (% of non-squamous cells)	36.7 (17.6–60.6)	54.3 (25.8−66.2)	0.4044
Blood eosinophils (/µL)	223 (116–594)	162 (92−228)	0.1534
Blood neutrophils (/µL)	4701 (3898–5796)	3988 (3162–4366)	0.1150
Total serum IgE (kU/L)	126 (66–280)	191 (49–489)	0.4587
CRP (mg/L)	2 (1–6)	2 (0.5–5)	0.6289
Fibrinogen (g/L)	4 (3–4)	4 (3–4)	0.8299
ICS daily dose (μg/day)	1000 (200–1700)	1225 (250–2000)	0.4299
ICS category (%)
Steroid naïve	5 (25%)	6 (25%)	0.349
Low dose	1 (5%)	2 (8%)
Medium dose	7 (35%)	3 (12%)
High dose	5 (25%)	13 (54%)
LABA, N (%)	15 (75)	15 (60)	0.352
LAMA, N (%)	1 (5)	5 (20)	0.205
OCS therapy, N (%)	2 (10)	4 (16)	0.678
Biologic therapy (anti-IgE)	0 (0)	1 (4)	1.000
Exacerbations in previous year	1 (0–1)	1 (0–1)	0.5916
Hospitalizations in previous year	0 (0–1)	0 (0–1)	0.9371

Notes: Comparison between airflow decline (FEV₁ decline (% predicted)/year >0) and no decline groups in asthma. Data are presented as mean ±SD or median and IQR. Low-dose ICS: <500μg/day; moderate-dose ICS: >500–1000μg/day; high-dose ICS: > 1000 μg/day beclomethasone dipropionate – chlorofluorocarbon.

Abbreviations: BMI, body mass index; BD, bronchodilation; FEV₁, forced expiratory volume in 1s; FVC, forced vital capacity; ACT, Asthma Control Test; ACQ, Asthma Control Questionnaire; AQLQ, Asthma Quality of Life Questionnaire; FeNO, fractional exhaled nitric oxide; ppb, parts per billion; ICS, inhaled corticosteroid; LABA, long-acting ß2-agonist; LAMA, long-acting muscarinic antagonist; OCS, oral corticosteroid.

Figure 1 Area under the receiver operating characteristic curves from the conditional inference forest binary classification of decliners versus non-decliners using 5, 10, 15, 25, 50, 100 VOCs of highest classification performance.

Abbreviation: AUC, area under the curve.