Hospitalization with acute exacerbation of chronic obstructive pulmonary disease and associated health resource utilization: A population-based Danish cohort study

Figures & data

Table 1. Descriptive statistics for patients hospitalized with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in the study period, by hospitalization in the year before study inclusion, Denmark, 2005–2009.

	Hospitalization for AECOPD in year before study inclusion	No hospitalization for AECOPD in year before study inclusion	Total
n	663	2513	3176
Age
Mean (SD)	71.5 (8.81)	71.0 (9.19)	71.1 (9.11)
Median	72.5	72.0	72.1
Interquartile range	65.9–77.9	65.1–77.7	65.2–77.7
Age group, n (%)
40–50	10 (1.5)	41 (1.6)	51 (1.6)
50–60	67 (10.1)	305 (12.1)	372 (11.7)
60–70	188 (28.4)	684 (27.2)	872 (27.5)
70–80	294 (44.3)	1082 (43.1)	1376 (43.3)
80–90	99 (14.9)	383 (15.2)	482 (15.2)
90+	5 (0.8)	18 (0.7)	23 (0.7)
Gender, n (%)
Female	343 (51.7)	1411 (56.1)	1754 (55.2)
Male	320 (48.3)	1102 (43.9)	1422 (44.8)
Comorbidities, n (%)
Myocardial infarction	69 (10.4)	119 (4.7)	188 (5.9)
Congestive heart failure	151 (22.8)	325 (12.9)	476 (15.0)
Peripheral vascular disease	55 (8.3)	148 (5.9)	203 (6.4)
Cerebrovascular disease	48 (7.2)	162 (6.4)	210 (6.6)
Dementia	10 (1.5)	19 (0.8)	29 (0.9)
Connective tissue disease	16 (2.4)	90 (3.6)	106 (3.3)
Peptic ulcer disease	33 (5.0)	98 (3.9)	131 (4.1)
Mild liver disease	5 (0.8)	17 (0.7)	22 (0.7)
Diabetes I and II	63 (9.5)	176 (7.0)	239 (7.5)
Diabetes with end organ damage	34 (5.1)	81 (3.2)	115 (3.6)
Hemiplegia	3 (0.5)	5 (0.2)	8 (0.3)
Moderate-to-severe renal disease	18 (2.7)	34 (1.4)	52 (1.6)
Any malignancy (except lung cancer)	40 (6.0)	145 (5.8)	185 (5.8)
Leukemia	3 (0.5)	2 (0.1)	5 (0.2)
Lymphoma	4 (0.6)	3 (0.1)	7 (0.2)
Moderate-to-severe liver disease	3 (0.5)	2 (0.1)	5 (0.2)
Metastatic solid tumor (except lung cancer)	2 (0.3)	2 (0.0)	4 (0.1)
AIDS	–	1 (0.0)	1 (0.0)
Alcoholism-related diseases	4 (0.6)	15 (0.6)	19 (0.6)
Atrial fibrillation/flutter	83 (12.5)	236 (9.4)	319 (10.0)
Obesity	30 (4.5)	99 (3.9)	129 (4.1)
Lung cancer	7 (1.1)	28 (1.1)	35 (1.1)
Asthma	140 (21.1)	340 (13.5)	480 (15.1)
Hypertension	93 (14.0)	325 (12.9)	418 (13.2)
Osteoporosis	99 (14.9)	206 (8.2)	305 (9.6)
Rheumatoid arthritis	2 (0.3)	30 (1.2)	32 (1.0)
Depression	23 (3.5)	62 (2.5)	85 (2.7)
Venous thromboembolism	23 (3.5)	65 (2.6)	88 (2.8)
CCI Score
Mean (SD)	1.0 (1.3)	0.66 (1.1)	0.7 (1.1)
Median	1.0	0.0	0.0
Interquartile range	0.0–1.0	0.0–1.0	0.0–1.0
CCI score group, n (%)
0	328 (49.5)	1547 (61.6)	1875 (59.0)
1	178 (26.8)	540 (21.5)	718 (22.6)
2	71 (10.7)	269 (10.7)	340 (10.7)
3+	86 (13)	157 (6.2)	243 (7.7)

CCI, Charlson comorbidity index.

Figure 1. Post-discharge mortality following hospitalizations for acute exacerbation of chronic obstructive pulmonary disease, Denmark, 2005–2009.

Table 2. Health resource utilization (HRU), recurrence rate, and mortality rate for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) hospitalizations, Denmark, 2005–2009.

	All AECOPD hospitalizations
Total	6612
LOS, days
Mean (SD)	7.8 (8.6)
Median	6
Interquartile range	3–9
ICU stay, n (%)
Overall LOS for hospitalizations  with ICU stay, days	569/6612 (8.6%)
Mean (SD)	16.3 (17.5)
Median	11
Interquartile range	7–20
Overall LOS for hospitalizations  without ICU stay, days
Mean (SD)	7.0 (6.7)
Median	5
Interquartile range	3–9
MV use, n (%)	193/6612 (2.9%)
NIV use, n (%)	479/6612 (7.2%)
Mortality, n (%)
In-hospital	372/6612 (5.6%)
30 days from discharge	265/6612 (4.2%)
60 days from discharge	484/6612 (7.8%)
90 days from discharge	653/6612 (10.5%)
180 days from discharge	1085/6612 (17.4%)
Recurrence, n (%)*
30 days from discharge
Readmission (inpatient)	830/6240 (13.3%)
MV	41/6240 (0.7%)
Simultaneous antibiotics and  steroid prescription	357/6240 (5.7%)
60 days from discharge
Readmission (inpatient)	1291/6240 (20.7%)
MV	78/6240 (1.3%)
Simultaneous antibiotics and  steroid prescription	596/6240 (9.6%)
90 days from discharge
Readmission (inpatient)	1589/6240 (25.5%)
MV	111/6240 (1.8%)
Simultaneous antibiotics and  steroid prescription	798/6240 (12.8%)
180 days from discharge
Readmission (inpatient)	2162/6240 (34.6%)
MV	179/6240 (2.9%)
Simultaneous antibiotics and  steroid prescription	1242/6240 (19.9%)

LOS, length of stay; SD, standard deviation; ICU, intensive care unit; MV, mechanical ventilation; NIV, non-invasive ventilation.

*Among hospital survivors (n = 6240).

Table 3. Characteristics of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) hospitalization events in the first 12 months of follow-up (2001 patients did not have an AECOPD in 2005).

	1st AECOPD hospitalization	2nd AECOPD hospitalization	3rd AECOPD hospitalization	4th AECOPD hospitalization	5th AECOPD hospitalization
n	1175	286	120	52	26
Time since previous hospitalization, days
Mean (SD)	–	80.7 (76.4)	69.1 (69.0)	44.3 (50.0)	43.9 (54.0)
Median	–	53.0	44.0	22.0	19.0
Interquartile range	–	19.0–127.0	18.5–98.0	9.0–64.0	12.0–59.0
LOS, days
Mean (SD)	8.2 (9.1)	7.3 (6.8)	6.5 (5.8)	8.3 (7.3)	5.8 (7.3)
Median	6	5	5	6	5
Interquartile range	3–10	3–9	3–9	3–10	2–7
ICU stay, n (%)	99/1175 (8.4%)	27/286 (9.4%)	6/120 (5.0%)	1/52 (1.9%)	2/26 (7.7%)
MV use, n (%)	48/1175 (4.1%)	10/286 (3.5%)	2/120 (1.7%)	–	–
NIV use, n (%)	69/1175 (5.9%)	14/286 (4.9%)	3/120 (2.5%)	1/52 (1.9%)	2/26 (7.7%)
Mortality, n (%)
In-hospital	70/1175 (6.0%)	11/286 (3.8%)	5/120 (4.2%)	–	1/26 (3.8%)
30 days from discharge	44/1175 (4.0%)	14/286 (5.1%)	5/120 (4.3%)	4/52 (7.7%)	2/26 (8.0%)
60 days from discharge	71/1175 (6.4%)	22/286 (8.0%)	11/120 (9.6%)	7/52 (13.5%)	2/26 (8.0%)
90 days from discharge	91/1175 (8.2%)	30/286 (10.9%)	16/120 (13.9%)	10/52 (19.2%)	4/26 (16.0%)
180 days from discharge	152/1175 (13.8%)	54/286 (19.6%)	33/120 (28.7%)	16/52 (30.8%)	6/26 (24.0%)
Recurrence, n (%)*
30 days from discharge
Readmission (inpatient)	104/1105 (9.4%)	53/275 (19.3%)	34/115 (29.6%)	16/52 (30.8%)	6/25 (24.0%)
MV	7/1105 (0.6%)	2/275 (0.7%)	–	–	–
Simultaneous antibiotics and   steroid prescription	41/1105 (3.7%)	11/275 (4.0%)	2/115 (1.7%)	3/52 (5.8%)	–
60 days from discharge
Readmission (inpatient)	162/1105 (14.7%)	81/275 (29.5%)	42/115 (36.5%)	24/52 (46.2%)	11/25 (44.0%)
MV	14/1105 (1.3%)	2/275 (0.7%)	–	–	–
Simultaneous antibiotics and   steroid prescription	78/1105 (7.1%)	18/275 (6.5%)	5/115 (4.3%)	4/52 (7.7%)	1/25 (4.0%)
90 days from discharge
Readmission (inpatient)	201/1105 (18.2%)	101/275 (36.7%)	53/115 (46.1%)	27/52 (51.9%)	12/25 (48.0%)
MV	16/1105 (1.4%)	5/275 (1.8%)	–	1/52 (1.9%)	–
Simultaneous antibiotics and   steroid prescription	107/1105 (9.7%)	30/275 (10.9%)	8/115 (7.0%)	6/52 (11.5%)	1/25 (4.0%)
180 days from discharge
Readmission (inpatient)	295/1105 (26.7%)	129/275 (46.9%)	69/115 (60.0%)	31/52 (59.6%)	15/25 (60.0%)
MV	21/1105 (1.9%)	9/275 (3.3%)	3/115 (2.6%)	1/52 (1.9%)	–
Simultaneous antibiotics and   steroid prescription	172/1105 (15.6%)	46/275 (16.7%)	18/115 (15.7%)	10/52 (19.2%)	2/25 (8.0%)

SD, standard deviation; LOS, length of stay; ICU, intensive care unit; MV, mechanical ventilation; NIV, non-invasive ventilation.

*Among hospital survivors.

Figure 2. Number of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) events per surviving patient during the study period.

Table 4. Odds ratios and 95% confidence intervals for predictors of hospitalization for acute exacerbations of chronic obstructive pulmonary disease (AECOPD).^a

Characteristic	Having 1 + AECOPD hospitalizations in the first 12 months of follow-up (n = 1175)	Having 2 + AECOPD hospitalizations in the first 12 months of follow-up (n = 286)
Age (per 10 year increase)	1.1 (1.0, 1.2)	1.4 (1.0, 1.8)
Gender (ref.: women)	1.1 (1.0, 1.3)	1.7 (1.1, 2.9)
Myocardial infarction	0.8 (0.5, 1.1)	2.6 (1.3, 5.4)
Congestive heart failure	0.9 (0.7, 1.2)	0.7 (0.3, 1.4)
Peripheral vascular disease	1.1 (0.8, 1.6)	1.2 (0.5, 2.7)
Cerebrovascular disease	0.9 (0.6, 1.2)	1.1 (0.4, 2.6)
Connective tissue disease	1.1 (0.7, 1.7)	0.4 (0.0, 2.7)
Peptic ulcer disease	1.1 (0.7, 1.6)	0.6 (0.1, 2.5)
Diabetes I and II	1.2 (0.9, 1.8)	1.8 (0.8, 4.2)
Diabetes with end organ failure	1.2 (0.7, 1.9)	0.6 (0.1, 2.4)
Any malignancy (except lung cancer)	0.9 (0.6, 1.3)	2.5 (1.2, 5.3)
Atrial fibrillation/flutter	1.0 (0.8, 1.3)	1.2 (0.6, 2.4)
Obesity	1.3 (0.9, 2.0)	1.4 (0.5, 4.3)
Asthma	1.3 (1.1, 1.6)	1.4 (0.8, 2.6)
Hypertension	1.1 (0.9, 1.4)	1.3 (0.7, 2.4)
Osteoporosis	1.5 (1.1, 1.9)	1.7 (0.8, 3.3)
Depression	1.6 (1.0, 2.5)	2.4 (0.8, 7.1)
Venous thromboembolism	0.9 (0.5, 1.4)	–
Prior year hospitalization with AECOPD	3.2 (2.6, 3.9)	2.3 (1.4, 4.0)
Prior year hospitalization with COPD but no AECOPD	1.8 (1.4, 2.3)	1.2 (0.6, 2.6)

*Only persons surviving at least 12 months are included (235 died during the 12 month period).