Risk of empyema in patients with COPD

Figures & data

Figure 1 Flowchart of subject enrollment.

Table 1 Demographic characteristics and comorbidities of patients with and without COPD

Variables	With COPD (n=55,136)	Without COPD (n=98,769)	P-value
Age, years
40–49	8,764 (15.9)	11,437 (11.6)	–
50–59	11,039 (20.0)	21,323 (21.6)
60–69	12,541 (22.7)	27,818 (28.2)
≥70	22,792 (41.3)	38,191 (38.7)
Mean (±SD)	65.4 (13.2)	65.7 (11.7)	–
Sex
Male	31,185 (56.6)	52,539 (53.2)	–
Female	23,951 (43.4)	46,230 (46.8)
Comorbidities
Diabetes	9,803 (17.8)	14,650 (14.8)	<0.001
Hypertension	24,189 (43.9)	33,002 (33.4)	<0.001
Chronic liver disease	5,909 (10.7)	6,630 (6.7)	<0.001
Stroke	7,509 (13.6)	7,865 (8.0)	<0.001
Cancer	751 (1.4)	890 (0.9)	<0.001
Chronic renal disease	958 (1.7)	1,152 (1.2)	<0.001

Table 2 Incidence of empyema in patients with and without COPD

Characteristics	COPD (55,136)			Non-COPD (98,769)			aHR (95% CI)	P-value
	Event	TFP (PY)	IR	Event	TFP (PY)	IR
Empyema	386	244,362.87	15.80	200	461,321.38	4.34	3.25 (2.73–3.87)	<0.001
Age
40–49	31	41,680.56	7.44	13	55,390.38	2.35	3.15 (1.65–6.02)	0.001
50–59	52	50,346.59	10.33	30	101,054.57	2.97	3.44 (2.20–5.40)	<0.001
60–69	79	59,593.92	13.26	61	142,218.16	4.29	3.08 (2.21–4.31)	<0.001
70 and above	224	92,741.79	24.15	96	162,658.27	5.90	4.03 (3.17–5.11)	<0.001
Sex
Male	307	136,358.61	22.51	141	241,609.18	5.84	3.82 (3.13–4.66)	<0.001
Female	79	108,004.26	7.314	59	219,712.20	2.69	2.72 (1.94–3.82)	<0.001
Comorbidities
Diabetes
Yes	77	40,652.56	18.94	49	64,748.28	7.57	2.48 (1.73–3.55)	<0.001
No	309	203,710.31	15.17	151	396,573.10	3.81	3.95 (3.25–4.80)	<0.001
Hypertension
Yes	176	105,678.82	16.65	87	148,456.57	5.86	2.82 (2.18–3.64)	<0.001
No	210	138,684.05	15.14	113	312,864.81	3.61	4.16 (3.31–5.23)	<0.001
Chronic liver disease
Yes	39	27,053.66	14.42	26	31,388.63	8.28	1.73 (1.06–2.85)	0.03
No	347	217,309.21	15.97	174	429,932.75	4.05	3.91 (3.26–4.69)	<0.001
Stroke
Yes	92	29,672.67	31.00	25	34,088.21	7.33	4.14 (2.66–6.45)	<0.001
No	294	214,690.20	13.69	175	427,233.18	4.10	3.32 (2.76–4.01)	<0.001
Cancer
Yes	10	1,911.98	52.30	3	3,118.55	9.62	4.52 (1.24–16.46)	0.022
No	376	242,450.88	15.51	197	458,202.84	4.30	3.58 (3.01–4.26)	<0.001
Chronic renal disease
Yes	11	3,248.93	33.86	3	4,084.66	7.34	4.59 (1.28–16.47)	0.019
No	375	241,113.94	15.55	197	457,236.72	4.31	3.58 (3.01–4.26)	<0.001

Abbreviations: aHR, adjusted hazard ratio; IR, incident rate per 10,000 person-years; PY, per 10,000 person-years; TFP, total follow-up period.

Table 3 Impact of comorbidities on empyema among COPD patients (n=55,136)

Comorbidity	Number (%)	Event	aHR (95% CI)	P-value
No comorbidity	20,285 (36.8)	126	–	–
Diabetes only	1,596 (2.9)	16	1.65 (0.98–2.78)	0.06
Hypertension only	10,271 (18.6)	68	1.05 (0.78–1.42)	0.73
Chronic liver disease only	1,788 (3.2)	14	1.24 (0.72–2.16)	0.44
Stroke only	1,612 (2.9)	17	1.88 (1.13–3.11)	0.02
Cancer only	271 (0.5)	5	4.84 (1.97–11.8)	0.001
Chronic renal disease only	153 (0.3)	3	3.90 (1.24–12.3)	0.02
≥1 comorbidity	34,851 (63.2)	260	1.25 (1.01–1.55)	0.04
≥2 comorbidities	17,152 (31.1)	129	1.29 (1.01–1.65)	0.04
≥3 comorbidities	6,057 (11.0)	53	1.54 (1.11–2.12)	0.01

Abbreviation: aHR, adjusted hazard ratio.

Figure 2 Cumulative incidence of empyema in patients with and without COPD.

Figure 3 Cumulative incidence of empyema in patients with only diabetes.

Figure 4 Cumulative incidence of empyema in patients with only stroke.

Figure 5 Cumulative incidence of empyema in patients with only cancer.