Patterns and characterization of COPD exacerbations using real-time data collection

Figures & data

Table 1 Demographic details of trial participants

Age (years)	53.80 (±9.65)
Male:female	30:16
FEV1%	42.33 (±14.5)
FEV1/FVC ratio	33.04 (±11.05)
Chronic bronchitis	32

Note: Data shown as mean (±SD) or number.

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; SD, standard deviation.

Table 2 Symptom length in exacerbations shown as median and interquartile range for both treated and untreated episodes

Symptom	Treated	Untreated	P-value
Worse than normal dyspnea	6 (4–13) days	4 (2–7) days	<0.001
Increased sputum volume	10 (5–18) days	6.5 (3–12.25) days	0.03
Increased sputum purulence	8 (4–13) days	6 (3–9) days	0.13

Note: The significance of differences between the groups (P) is shown.

Figure 1 Length of untreated and treated exacerbations is shown as a box and whisker plot.

Notes: The bold horizontal line is the median value. The box is the interquartile range and the bars represent the 95% confidence interval with outliers shown as open circles and extreme outliers shown with asterisks.

Figure 2 Exacerbation treatment by Anthonisen type and symptom predominance.

Notes: (A) The proportion of exacerbations that were treated is shown for each of the three Anthonisen categories. (B) Anthonisen type 3 exacerbations are shown divided into the proportion of each that were treated episodes; worse than normal dyspnea and increased sputum volume or purulence.

Table 3 Variables in the equation for logistic regression of all exacerbations

Variable	B	SE	Sig	Exp(B)	95% CI for Exp(B)
					Lower	Upper
SOB	0.19	0.04	0.00	1.20	1.11	1.30
SpVol	−0.04	0.03	0.18	0.96	0.91	1.02
SpCol	−0.03	0.02	0.25	0.97	0.93	1.02
AT type			0.00
AT type 1	2.42	0.58	0.00	11.19	3.61	34.67
AT type 2	1.35	0.40	0.00	3.84	1.83	8.07
Constant	−1.36	0.29	0.00	0.26

Note: The significance (P) of the variable impact is shown as significance.

Abbreviations: AT, Anthonisen; CI, confidence interval; SE, standard error; Sig, significance; SOB, dyspnea score; SpVol, length of those with new or increased sputum volume; SpCol, length of episodes with new or increased sputum purulence.

Table 4 Logistic regression of exacerbations in patients with chronic bronchitis

Variable	B	SE	Sig	Exp(B)	95% CI for Exp(B)
					Lower	Upper
SOB	0.23	0.06	0.00	1.25	1.13	1.4
SpVol	−0.12	0.05	0.01	0.88	0.81	0.96
SpCol	−0.02	0.03	0.42	0.98	0.93	1.03
AT type			0.00
AT type 1	3.37	0.76	0.00	28.95	6.52	128.57
AT type 2	1.60	0.47	0.00	4.96	2.00	12.37
Constant	−1.63	0.38	0.00	0.20

Abbreviations: AT, Anthonisen; CI, confidence interval; SE, standard error; Sig, significance; SOB, dyspnea score; SpVol, length of those with new or increased sputum volume; SpCol, length of episodes with new or increased sputum purulence.

Table 5 Logistic regression of exacerbation episodes in patient without chronic bronchitis

Variable	B	SE	Sig	Exp(B)	95% CI for Exp(B)
					Lower	Upper
SOB	0.16	0.08	0.03	1.18	1.01	1.36
SpVol	0.04	0.05	0.38	1.04	0.95	1.15
SpCol	−0.03	0.07	0.65	0.97	0.85	1.11
AT type			0.43
AT type 1	1.09	1.06	0.31	2.97	0.37	23.80
AT type 2	0.85	0.74	0.26	2.33	0.54	10.01
Constant	−1.15	0.54	0.03	0.32

Abbreviations: AT, Anthonisen; CI, confidence interval; SE, standard error; Sig, significance; SOB, dyspnea score; SpVol, length of those with new or increased sputum volume; SpCol, length of episodes with new or increased sputum purulence.

Figure 3 Patterns of exacerbations.

Notes: (A) Classical Anthonisen type 1 exacerbations SOB, sputum volume, sputum color. (B) Reset baseline with increased sputum production following treated exacerbations. Treatment started on day 1 and finished on day 11. (C) Reset baseline with reduction in sputum volume following a treated exacerbation. Treatment started on day 3 and finished on day 27. Dyspnea was scored on a 4-point scale (2= normal or usual for me, 3= worse than usual, 4= much worse than usual, and 1= better than usual), daily sputum volume was scored as none =(0), 1= (up to a teaspoonful), 2= (up to a tablespoonful), 3= (up to an egg-cupful), 4= (more than an egg-cupful), and sputum color was assessed using the Bronkotest color chart (1–2 being mucoid and 3, 4, and 5 being increasing purulence).
Abbreviation: SOB, dyspnea score.

Figure S1 Exacerbation in which only one symptom (dyspnea) oscillates for >3 weeks before all other major Anthonisen symptoms deteriorate.

Notes: Dyspnea was scored on a 4-point scale (2= normal or usual for me, 3= worse than usual, 4= much worse than usual, and 1= better than usual), daily sputum volume was scored as none =(0), 1= (up to a teaspoonful), 2= (up to a tablespoonful), 3= (up to an egg-cupful), 4= (more than an egg-cupful), and sputum color was assessed using the Bronkotest color chart (1–2 being mucoid and 3, 4, and 5 being increasing purulence).

Abbreviation: SOB, dyspnea score.