Markers of exacerbation severity in chronic obstructive pulmonary disease

Respiratory Research

Table 2 Typical Subject Demographics According to ATS/ERS 2004 Exacerbation Severity Level

Variable/Exacerbation Severity Level^†	Total Studies*	Total Subjects^#	Point Estimate (95% CI)	Study Data Distributions (± 2SD)	Significance Test^‡
					Z Test	P Value
Age (years)	182	27,930			Levels
Level I	71	16,917	66.0 (64.6 – 67.4)	51.2 – 80.8	I vs. II	0.067 (NS)
Level II	70	7,300	64.2 (62.9 – 65.5)	52.1 – 76.3	II vs. III	0.002
Level III	43	3,713	68.0 (65.9 – 70.1)	53.0 – 83.0	I vs. III	0.12 (NS)
Height (cm)	27	3,154			Levels
Level I	14	2,581	169.7 (166.4 – 173.0)	155.1 – 184.3	I vs. II	0.25 (NS)
Level II	9	247	167.1 (164.0 – 170.2)	157.5 – 176.6	II vs. III	0.54 (NS)
Level III	4	326	169.1 (163.4 – 174.7)	157.3 – 180.9	I vs. III	0.85 (NS)
Weight (kg)	37	4,168			Levels
Level I	15	3,176	72.8 (67.5 – 78.1)	46.9 – 98.7	I vs. II	0.36 (NS)
Level II	12	290	69.3 (63.8 – 74.7)	49.4 – 89.1	II vs. III	0.26 (NS)
Level III	10	702	63.6 (55.3 – 71.9)	35.5 – 91.7	I vs. III	0.067 (NS)
Body-Mass Index (kg/m ² )	29	4,250			Levels
Level I	6	2,273	26.2 (23.8 – 28.7)	18.5 – 34.0	I vs. II	0.037 (NS)
Level II	19	1,729	23.4 (22.4 – 24.4)	19.5 – 27.3	II vs. III	0.84 (NS)
Level III	7	248	23.6 (21.2 – 26.0)	17.1 – 30.1	I vs. III	0.14 (NS)
Disease Years	21	8,606			Levels
Level I	15	8,354	10.9 (7.8 – 14.1)	0 – 26.4	I vs. II	0.65 (NS)
Level II	5	228	12.9 (5.0 – 20.8)	0 – 30.2	II vs. III	0.67 (NS)
Level III	2	24	16.2 (3.9 – 28.4)	0 – 33.5	I vs. III	0.42 (NS)

Symbols and Abbreviations: *Bold numbers indicate total studies (without duplicates) for the specific variable of interest; # Bold numbers indicate total subjects for all COPD exacerbation severity levels with respect to the specific variable of interest; † Exacerbation severity levels are based on the following ATS/ERS 2004 operational classification scheme: Level I – treated at home; Level II – requires hospitalisation ; and Level III – leads to respiratory failure; ‡ Exacerbation Levels II and III were each compared to Level I using a two-tailed Z-test in which the alpha level was adjusted according to the Bonferroni Correction procedure to account for multiple testing; and NS = Non-significant difference.

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