Medical Utilization and Cost in Patients with Overlap Syndrome of Chronic Obstructive Pulmonary Disease and Asthma

Figures & data

Table 1.  Patient characteristics

Characteristics	Overlap syndrome (n = 101,004)	COPD without asthma (n = 84,143)	p-value
Males (%)	68,025 (67.3%)	48,464 (57.6%)	<0.001
Mean age, years	69.7 ± 10.7	70.3 ± 10.5	<0.001
Number of patients in each age group (%)
40–49 years	4,345 (4.3%)	3,784 (4.5%)
50–59 years	12,498 (12.4%)	9,450 (11.2%)
60–69 years	28,237 (28.0%)	22,376 (26.6%)
70–79 years	39,405 (39.0%)	32,658 (38.8%)
>80 years	16,519 (16.4%)	15,875 (18.9%)
Medical aid^#	17,643 (17.5%)	12,965 (15.4%)	<0.001
Type of hospital use			<0.001
Primary	44,379 (43.9%)	57,192 (68.0%)
Secondary	9,676 (9.6%)	6,117 (7.3%)
Tertiary	46,583 (46.1%)	20,834 (24.8%)
Hospitalizations^†	30,807 (30.5%)	11,884 (14.1%)	<0.001
ICU care^†	477 (0.5%)	158 (0.2%)	<0.001
ER visits^†	14,733 (14.6%)	4,222 (5.0%)	<0.001
Mean number of visits	1.5 ± 1.0	1.2 ± 0.5	<0.001
Number of patients in each group (%)
0 visit	86,271 (85.4%)	79,921 (95.0%)
1–2 visits	13,243 (13.1%)	4,090 (4.9%)
3–4 visits	1,203 (1.2%)	122 (0.1%)
>5 visits	287 (0.3%)	10 (0.0%)
Chest X-rays	21,092 (20.9%)	17,538 (20.8%)	0.836
Chest CTs	791 (0.8%)	409 (0.5%)	<0.001
PFTs	41,931 (41.5%)	15,321 (18.2%)	<0.001
Hospitalizations in the last year*	14,637 (14.5%)	5,105 (6.1%)	<0.001
Co-morbidity
Ischemic heart disease	9,053 (9.0%)	7,100 (8.4%)	<0.001
Osteoporosis	5,267 (5.2%)	3,650 (4.3%)	<0.001
Depressive disorder	2,080 (2.1%)	1,316 (1.6%)	<0.001
Arthritis	3,484 (3.4%)	3,658 (4.3%)	<0.001
Diabetes mellitus	13,540 (13.4%)	10,926 (13.0%)	0.008
Pneumothorax	1,271 (1.3%)	527 (0.6%)	<0.001
Congestive heart failure	5,542 (5.5%)	4,813 (5.7%)	0.029
Hypertension	30,020 (29.7%)	24,186 (28.7%)	<0.001
Anemia	1,643 (1.6%)	1,365 (1.6%)	0.940
Metabolic syndrome	6,686 (6.6%)	5,483 (6.5%)	0.720

Data are expressed as the mean ± SD or the number of patients (with percentage in parentheses).^#Patients with low socioeconomic status were covered by medical aid in Korea. Medical cost was covered by government for patients with medical aid.^†Number of patients who were hospitalized, cared for in the ICU, and visited the ER in the year 2009.*Number of patients who were hospitalized in the year 2008.ER = emergency room; CT = computed tomography; PFT = pulmonary function test.

Table 2.  Healthcare utilization of COPD patients^†

	Overlap syndrome	COPD without asthma	p-value
Cost of all medical utilization (USD)
Cost of outpatient services	790 ± 71	413 ± 512	<0.001
Cost of inpatient services	3,373 ± 4,628	3,010 ± 5,013	<0.001
Total cost	1,807 ± 3,096	829 ± 2,215	<0.001
Used days
Outpatient services	9.2 ± 9.76	7.4 ± 8.11	<0.001
Inpatient services	25.44 ± 34.74	23.19 ± 36.41	<0.001
Total used days	16.81 ± 24.56	10.5 ± 17.46	<0.001

Data are expressed as the mean ± SD.

^†Costs or used days per person. Costs and used days are restricted to COPD-related ones.

Table 3.  Total cost in the USD of all medical utilization of COPD patients and the proportion of medical utilization.

	Overlap syndrome		COPD without asthma
	Sum	%	Sum	%
Outpatient services
Medical examination	3,569,931	4.55%	1,482,296	4.36%
Radiologic examination	1,045,169	1.33%	481,453	1.42%
Medication	63,767,200	81.20%	25,919,388	76.32%
Others	10,028,548	12.91%	6,078,520	17.90%
Total cost	78,527,082	100.00%	33,961,656	100.00%
Inpatient services
Medical examination	18,974,697	18.03%	6,082,634	16.69%
Radiologic examination	3,941,917	3.74%	1,489,646	4.09%
Medication	28,680,165	27.25%	9,365,771	25.70%
Others	53,662,667	50.98%	19,508,004	53.53%
Total cost	105,259,446	100.00%	36,446,055	100.00%
Total
Medical examination	22,544,628	12.27%	7,564,930	10.74%
Radiologic examination	4,987,129	2.71%	1,971,099	2.80%
Medication	92,447,366	50.30%	35,285,159	50.11%
Others	63,807,405	34.72%	25,586,523	36.34%
Total cost	183,786,528	100.00%	70,407,710	100.00%

Medical examination includes all examinations (which includes laboratory examination, pulmonary function test, and echocardiography) except radiological examinations.

Table 4.  The frequency of medication use.

	Overlap syndrome		COPD without asthma
Medication	n	(%)	n	(%)	p-value
ICS	16,271	16.1%	2,994	3.6%	<0.001
ICS+LABA	50,963	50.5%	6,480	7.7%	<0.001
LAMA	39,782	39.4%	14,877	17.7%	<0.001
LABA	83	0.1%	51	0.1%	0.086
LTRA	30,690	30.4%	3,380	4.0%	<0.001
OCS	36,631	36.3%	13,485	16.0%	<0.001
SAMA	22,702	22.5%	6,364	7.6%	<0.001
SABA	41,817	41.4%	11,570	13.8%	<0.001
SABAι+SAMA	3,245	3.2%	1,330	1.6%	<0.001
Systemic beta agonist	49,107	48.6%	36,815	43.8%	<0.001
Theophylline	81,683	80.9%	63,826	75.9%	<0.001

LAMA = long-acting muscarinic antagonist; LABA = long-acting beta-2 agonist; ICS = inhaled corticosteroids; ICS+LABA = ICS plus LABA; LTRA = leukotriene antagonist; OCS = oral corticosteroids; SAMA = short-acting muscarinic antagonist; SABA = short-acting beta-2 agonist; SABA+SAMA = SABA plus SAMA.

Table 5.  Cost of medication (USD)

	Overlap syndrome			COPD without asthma
Medication	n	Total cost	Cost per person	n	Total cost	Cost per person	p-value^†
ICS	16,260	733,065	45 ± 81	2,991	80,768	27 ± 58	<0.001
ICS+LABA	50,893	12,579,822	247 ± 188	6,471	1,146,991	177 ± 167	<0.001
LAMA	39,754	10,886,969	274 ± 347	14,862	4,013,086	270 ± 406	0.308
LABA	83	6,354	77 ± 64	51	5,415	106   ± 70	0.013
LTRA	30,652	5,521,407	180 ± 167	3,376	316,137	94  ± 127	<0.001
OCS	36,588	224,819	6  ± 17	13,472	55,144	4  ± 13	<0.001
SAMA	22,689	558,096	25 ± 57	6,360	111,408	18 ± 40	<0.001
SABA	41,772	713,180	17 ± 34	11,558	130,579	11  ± 152	<0.001
SABA+SAMA	3,244	157,000	48 ± 65	1,330	49,372	37 ± 51	<0.001
Systemic beta agonist	49,066	1,758,055	36 ± 56	36,791	861,244	23 ± 46	<0.001
Theophylline	81,621	3,404,787	42 ± 44	63,789	1,518,381	24 ± 35	<0.001

^†The p-value applies to the comparison of cost per person.

Data are expressed as the mean ± SD.

LAMA = long-acting muscarinic antagonist; LABA = long-acting beta-2 agonist; ICS = inhaled corticosteroids; ICS+LABA = ICS plus LABA; LTRA = leukotriene antagonist; OCS = oral ­corticosteroids; SAMA = short-acting muscarinic antagonist; SABA = short-acting beta-2 agonist; SABA+SAMA = SABA plus SAMA.

Table 6.  Multiple linear regression analysis of factors affecting medical cost

	Unadjusted			Adjusted
Variable	β	exp (β)	p-value	β	exp (β)	p-value
Age (year)	0.015	1.015	<0.001	0.012	1.012	<0.001
Male gender	0.530	1.699	<0.001	0.276	1.317	<0.001
Overlap syndrome	1.082	2.951	<0.001	0.645	1.907	<0.001
Hospitalization in the last year	1.319	3.740	<0.001	0.753	2.122	<0.001
Medical aid^#	0.613	1.845	<0.001	0.474	1.605	<0.001
Type of hospital use	0.790	2.204	<0.001	0.568	1.764	<0.001

^#Patients with low socioeconomic status were covered by medical aid in Korea. Medical cost was covered by government for patients with medical aid.

Table 7.  Multiple linear regression analysis of factors affecting used days

	Unadjusted			Adjusted
Variable	β	exp (β)	p-value	β	exp (β)	p-value
Age (year)	0.012	1.012	<0.001	0.011	1.011	<0.001
Male gender	0.176	1.192	<0.001	0.120	1.127	<0.001
Overlap syndrome	0.456	1.578	<0.001	0.323	1.381	<0.001
Hospitalization in the last year	0.824	2.280	<0.001	0.579	1.785	<0.001
Medical aid^#	0.437	1.548	<0.001	0.348	1.416	<0.001
Type of hospital use	0.598	1.818	<0.001	0.274	1.315	<0.001

^#Patients with low socioeconomic status were covered by medical aid in Korea. Medical cost was covered by government for patients with medical aid.