Table 3 Comparison of the median intra-patient coefficient of variation (CV) for each mediator using daily data, a 3-day rolling mean and a 5-day rolling mean

	IL-1β (pM)	TNFα (pM)	CXCL8 (nM)	MPO (mg/l)	LTB4 (nM)	GROα (pM)	Sputum neutrophils(106/ml)	Sputum macrophages(106/ml)
Raw data
Median CV (%)	19.4	30.3	30.8	79.3	39.9	16.2	77.3	74.2
IQR	11–33	13–88	19–63	53–138	22–165	10–29	42–180	41–102
3-day rolling mean
Median CV (%)	11.2*	20.6*	17.3*	44.5*	22.5*	7.6*	46.7	33.9*
IQR	6–17	8–50	7–23	20–60	10–96	4–11	13–218	26–59
5-day rolling mean
Median CV (%)	6.9*†	12.2*†	9.5*†	22*†	13.8*†	4.1*†	13.4*†	20*
IQR	4–9	2–37	4–20	13–39	4–53	2.6–6.8	8–124	13–32

The median coefficient of variation (CV) has been derived from the marker-specific CV from each patient. Differences in CVs were assessed using the Friedman matched samples test and the Wilcoxon matched pairs signed rank test.
IL-1β, interleukin 1β; TNFα, tumour necrosis factor α; CXCL8, interleukin 8; MPO, myeloperoxidase; LTB4, leucotriene B4; GROα, growth-related oncogene α; IQR, interquartile range.
*Significant reduction in mean CV from raw data (p<0.05).
†Significant reduction in mean CV from 3-day rolling mean (p<0.05).