Pulmonary biomarkers in COPD exacerbations: a systematic review

Table 1 Assessment of FeNO in ECOPD

Ref.	Course:	At ECOPD onset		Course:	Comment
	From Baseline to	FeNO levels	Comparisons	After ECOPD
	ECOPD Onset	(ppb)		onset
Agusti et al. [10]		€41.0 ± 5.1, † 5.7-76.5	ECOPD > controls	↓	GCS. ↓ by M1-2 or by M6-8
Al-Ali et al. [11]		£10.3 (2.7-34)	↔ECOPD, controls, pneumonia
Al-Ali et al. [11]		£10.3 (2.7-34)	↔ECOPD smokers, ex smokers
Antus et al. [12]		¥25.3 (21.2–30.1)		↓	GCS. ↓ by discharge
Antus et al. [13]		¥23.8 (19.4–29.7)	↔ECOPD smokers, ex smokers	↓	↓ by discharge
Bhowmik et al. [14]	↑*	#7.40 (4.80–9.60)		↓*	Exact time points N/R
Cosio et al. [15]		N/R		↓	GCS. ↓ by M3
Kersul et al. [16]		N/R	N/R	↓	GCS. ↓ by M3 after discharge
Lazar et al. [17]		‡10 (7)	↔ECOPD, controls (non-smokers, smokers)	N/R	Time points: admission, discharge
Papi et al. [18]		€15.18 ±1.85		↓	GCS. ↓ by W8-10

The columns concerning the course of FeNO refer to longitudinal studies (paired samples) and the column concerning comparisons at ECOPD onset refers to cross-sectional studies (unpaired samples).
Abbreviations: D day after ECOPD onset, FeNO fraction of exhaled nitric oxide, GCS administration of systemic glucocorticosteroids, M months after ECOPD onset, N/R not reported, ppb parts per billion, W weeks after ECOPD onset.
Symbols: ↔: no difference, ↑: increase, ↓: decrease, € mean ± SEM, † range, £ median (range), ¥ geometric mean (95% CI), # Median (interquartile range), ‡ mean (SD), *: stability samples obtained before and after the ECOPD.