Differences in health care outcomes between postdischarge COPD patients treated with inhaled corticosteroid/long-acting β₂-agonist via dry-powder inhalers and pressurized metered-dose inhalers

Figures & data

Figure 1 Patient selection.

Abbreviations: AECOPD, acute exacerbation of COPD; DPI, dry powder inhaler; ICS, inhaled corticosteroid; LABA, long-acting β₂-agonist; pMDI, pressurized metered-dose inhaler.

Table 1 Demographic and clinical characteristics

	DPI (N=1,960)		pMDI (N=1,086)		P-value
	n/mean	%/SD	n/mean	%/SD
Demographicsa
Age (years), mean, SD	67.7	12.1	67.5	11.9	0.60
Age (years) (n, %)
40–44	27	1.4%	14	1.3%	0.74
45–49	84	4.3%	40	3.7%
50–54	145	7.4%	94	8.7%
55–59	280	14.3%	161	14.8%
60–64	379	19.3%	197	18.1%
65+	1,045	53.3%	580	53.4%
Male (n, %)	903	46.1%	509	46.9%	0.67
Geographic region (n, %)
Northeast	381	19.4%	160	14.7%	<0.0001
North Central	696	35.5%	443	40.8%
South	638	32.6%	408	37.6%
West	226	11.5%	65	6.0%
Unknown	19	1.0%	10	0.9%
Insurance plan type (n, %)
Comprehensive/indemnity	636	32.4%	371	34.2%	<0.01
EPO/PPO	874	44.6%	457	42.1%
POS/POS with capitation	120	6.1%	47	4.3%
HMO	194	9.9%	129	11.9%
CDHP/HDHP	62	3.2%	54	5.0%
Unknown	74	3.8%	28	2.6%
Payer (n, %)
Commercial	884	45.1%	487	44.8%	0.89
Medicare supplemental	1,076	54.9%	599	55.2%
Rural residence indicator (n, %)
Urban	1,551	79.1%	849	78.2%	0.80
Rural	390	19.9%	227	20.9%
Unknown	19	1.0%	10	0.9%
Clinical characteristicsb
Deyo–Charlson comorbidity index, mean, SD	2.4	1.8	2.4	1.8	0.62
Comorbid conditions (n, %)
Acute bronchitis and bronchiolitis	654	33.4%	370	34.1%	0.69
Anxiety	234	11.9%	139	12.8%	0.49
Cardiovascular disease	509	26.0%	286	26.3%	0.83
Acute myocardial infarction	78	4.0%	25	2.3%	0.01
Congestive heart failure	462	23.6%	250	23.0%	0.73
Ischemic stroke	33	1.7%	30	2.8%	0.045
Depression	301	15.4%	151	13.9%	0.28
Diabetes (type I or II)	524	26.7%	310	28.5%	0.28
Gastroesophageal reflux disease	233	11.9%	147	13.5%	0.19
Hypertension	1,282	65.4%	734	67.6%	0.22
Osteoarthritis	304	15.5%	159	14.6%	0.52
Osteoporosis	92	4.7%	41	3.8%	0.23
Pneumonia	681	34.7%	378	34.8%	0.97
Antihypertensive medication (n, %)	1,332	68.0%	768	70.7%	0.12
Diabetes medication (n, %)	411	21.0%	240	22.1%	0.47
Lipid-lowering medication (n, %)	916	46.7%	534	49.2%	0.20
Respiratory treatments (n, %)
Oxygen therapy	384	19.6%	191	17.6%	0.18
Nebulizer use	208	10.6%	127	11.7%	0.36
Maintenance medicationsa
ICS	92	4.7%	58	5.3%	0.43
LABA	21	1.1%	15	1.4%	0.45
Long-acting muscarinic antagonist	118	6.0%	66	6.1%	0.95
Methylxanthines	20	1.0%	18	1.7%	0.13
Phosphodiesterase-4 inhibitors	2	0.1%	2	0.2%	0.55
SABA	714	36.4%	436	40.1%	0.04
Short-acting muscarinic antagonist	73	3.7%	50	4.6%	0.24
Systemic corticosteroids	842	43.0%	505	46.5%	0.06
Macrolide antibiotics	686	35.0%	406	37.4%	0.19
Single fill of a macrolide	464	67.6%	271	66.7	0.76
Multiple fills of a macrolide	222	32.4	135	33.3
Leukotriene modifiers	76	3.9%	42	3.9%	0.99
Preindex use of index ICS/LABA inhaler type,^c,d N, %	95	4.8%	411	37.8%	<0.0001
COPD severity, mean, SD
Number of hospitalization days due to AECOPD	3.7	2.5	4.0	2.9	0.01
Number of pulmonologist visits	1.6	3.8	1.9	4.1	0.03
Number of SABA fills	1.0	2.4	1.2	2.6	0.09
Number of oral corticosteroid fills	0.9	1.8	1.0	1.7	0.22

Notes:

a Assessed on the index date.

b Assessed during the 12-month preindex period.

c All patients with a preindex ICS + LABA had an index date in 2010.

d Any ICS + LABA, ICS alone, LABA alone, or SABA medication delivered via DPI/pMDI.

Abbreviations: AECOPD, acute exacerbation of COPD; CDHP, consumer-driven health plan; DPI, dry powder inhaler; EPO, exclusive provider organization; HDHP, high deductible health plan; HMO, health maintenance organization; ICS, inhaled corticosteroid; LABA, long-acting β₂-agonist; pMDI, pressurized metered-dose inhaler; POS, point of service; PPO, preferred provider organization; SABA, short-acting β-agonist.

Table 2 Health care resource utilization and costs in the 12-month preindex period

	DPI (N=1,960)			pMDI (N=1,086)			P-value
	n/mean	%/SD	Median	n/mean	%/SD	Median
All-cause utilization
Inpatient admissions (n, %)	1,956	99.8%		1,083	99.7%		0.69
Average number of admissions (mean, SD, median)	2.2	1.9	2.0	2.2	2.0	2.0	0.73
Average length of stay for inpatient admissions, days (mean, SD, median)	3.7	2.3	3.0	3.8	2.3	3.3	0.14
Outpatient ER visits (n, %)	941	48.0%		473	43.6%		0.02
Physician office visits (n, %)	1,796	91.6%		1,003	92.4%		0.48
Outpatient laboratory and radiology procedures (n, %)	1,446	73.8%		818	75.3%		0.35
Other outpatient services (n, %)	1,901	97.0%		1,065	98.1%		0.08
Outpatient pharmacy (n, %)	1,860	94.9%		1,041	95.9%		0.23
Average number of prescriptions (all medications) filled (mean, SD, median)	37.9	32.6	30.0	39.1	33.6	31.0	0.35
All-cause costs
Total costs PPPM (mean, SD, median)	$2,705	$4,229	$1,637	$2,509	$2,515	$1,662	0.11
Total medical costs PPPM (mean, SD, median)	$2,383	$4,111	$1,345	$2,197	$2,415	$1,381	0.12
Inpatient	$1,459	$2,475	$847	$1,411	$1,659	$891	0.52
Outpatient	$923	$2,944	$357	$786	$1,441	$391	0.09
ER	$55	$170	$0	$53	$156	$0	0.69
Physician office visits	$76	$79	$55	$74	$66	$58	0.50
Outpatient laboratory and radiology procedures	$46	$163	$10	$59	$509	$10	0.43
Other outpatient services	$747	$2,840	$236	$601	$1,200	$242	0.05
Outpatient pharmacy costs PPPM (mean, SD, median)	$322	$560	$171	$311	$464	$165	0.57
COPD-related utilization
Inpatient admissions (n, %)	1,954	99.7%		1,081	99.5%		0.50
Average number of admissions (mean, SD, median)	1.2	0.5	1.0	1.2	0.7	1.0	0.27
Average length of stay for inpatient admissions, days (mean, SD, median)	3.5	2.2	3.0	3.7	2.3	3.0	0.04
Outpatient ER visits (n, %)	380	19.4%		171	15.7%		0.01
Physician office visits (n, %)	660	33.7%		408	37.6%		0.03
Outpatient laboratory and radiology procedures (n, %)	268	13.7%		169	15.6%		0.15
Other outpatient services (n, %)	1,075	54.8%		610	56.2%		0.48
Outpatient pharmacy (n, %)	1,406	71.7%		802	73.8%		0.21
Average number of prescriptions (all medications) filled (mean, SD, median)	3.8	5.3	2.0	4.2	6.0	2.0	0.03
COPD-related costs
Total costs PPPM (mean, SD, median)	$1,128	$1,076	$831	$1,180	$1,150	$861	0.23
Total medical costs PPPM (mean, SD, median)	$1,106	$1,069	$811	$1,155	$1,144	$838	0.24
Inpatient	$1,033	$1,031	$758	$1,079	$1,092	$795	0.26
Outpatient	$73	$190	$16	$77	$230	$13	0.61
ER	$13	$68	$0	$13	$75	$0	0.99
Physician office visits	$7	$16	$0	$8	$16	$0	0.16
Outpatient laboratory and radiology procedures	$4	$27	$0	$4	$27	$0	0.83
Other outpatient services	$48	$145	$2	$51	$193	$2	0.66
Outpatient pharmacy costs PPPM (mean, SD, median)	$23	$61	$3	$24	$62	$4	0.47

Note: All costs are presented in USD.

Abbreviations: DPI, dry powder inhaler; ER, emergency room; pMDI, pressurized metered-dose inhaler; PPPM, per person per month.

Table 3 All-cause and COPD-related HRU and costs in the 90-day postindex period

	DPI (N=1,960)			pMDI (N=1,086)			P-value
	n/mean	%/SD	Median	n/mean	%/SD	Median
All-cause utilization
Inpatient admissions (n, %)	211	10.8%		119	11.0%		0.87
Average number of admissions (mean, SD, median)	0.1	0.5	0.0	0.1	0.5	0.0	0.88
Average length of stay for inpatient admissions (days) (mean, SD, median)	0.5	1.9	0.0	0.5	2.7	0.0	0.51
Outpatient ER visits (n, %)	356	18.2%		183	16.9%		0.36
Physician office visits (n, %)	1,785	91.1%		991	91.3%		0.87
Outpatient laboratory and radiology procedures (n, %)	1,006	51.3%		557	51.3%		0.98
Other outpatient services (n, %)	1,794	91.5%		998	91.9%		0.73
Outpatient pharmacy (n, %)	1,960	100.0%		1,086	100.0%
Average number of prescriptions (all medications) filled (mean, SD, median)	15.9	9.5	14.0	16.1	9.7	14.0	0.55
Average number of ICS/LABA prescriptions filled (mean, SD, median)	1.6	0.8	1.0	1.6	0.8	1.0	0.99
All-cause costs
Total costs PPPM (mean, SD, median)	$2,992	$6,461	$1,168	$2,623	$5,546	$1,147	0.10
Total medical costs PPPM (mean, SD, median)	$2,420	$6,389	$574	$2,056	$5,425	$538	0.10
Inpatient	$925	$4,878	$0	$834	$4,438	$0	0.60
Outpatient	$1,495	$3,641	$521	$1,222	$2,114	$486	0.009
ER	$96	$510	$0	$71	$312	$0	0.09
Physician office visits	$133	$117	$108	$129	$108	$105	0.38
Outpatient laboratory and radiology procedures	$59	$253	$0	$57	$276	$0	0.87
Other outpatient services	$1,208	$3,470	$335	$965	$1,935	$317	0.013
Outpatient pharmacy costs PPPM (mean, SD, median)	$572	$593	$420	$567	$714	$396	0.84
COPD-related utilization
Inpatient admissions (n, %)	64	3.3%		32	2.9%		0.63
Average number of admissions (mean, SD, median)	0.0	0.2	0.0	0.0	0.2	0.0	0.57
Average length of stay for inpatient admissions, days (mean, SD, median)	0.1	0.8	0.0	0.1	0.6	0.0	0.45
Outpatient ER visits (n, %)	123	6.3%		56	5.2%		0.21
Physician office visits (n, %)	1,188	60.6%		650	59.9%		0.68
Outpatient laboratory and radiology procedures (n, %)	239	12.2%		128	11.8%		0.74
Other outpatient services (n, %)	1,243	63.4%		680	62.6%		0.66
Outpatient pharmacy (n, %)	1,960	100.0%		1,086	100.0%
Average number of prescriptions filled (mean, SD, median)	4.4	2.6	4.0	4.2	2.6	4.0	0.16
Tiotropium use within 30 days after index date (n, %)	118	6.0%		47	4.3%		0.048
COPD-related costs
Total costs PPPM (mean, SD, median)	$169	$467	$83	$136	$253	$73	0.011
Total medical costs PPPM (mean, SD, median)	$112	$461	$25	$85	$247	$20	0.037
Inpatient	$37	$382	$0	$27	$200	$0	0.34
Outpatient	$75	$232	$24	$58	$129	$20	0.010
Roomer	$7	$63	$0	$3	$24	$0	0.05
Physician office visits	$11	$14	$7	$10	$13	$7	0.16
Outpatient laboratory and radiology procedures	$2	$17	$0	$1	$7	$0	0.13
Other outpatient services	$56	$211	$8	$43	$120	$7	0.040
Outpatient pharmacy costs PPPM (mean, SD, median)	$57	$44	$43	$51	$40	$35	<0.0001

Note: All costs are presented in USD.

Abbreviations: DPI, dry powder inhaler; ER, emergency room; HRU, health care resource use; pMDI, pressurized metered-dose inhaler; PPPM, per person, per month.

Figure 2 Kaplan–Meier curves comparing time (in days) from index date to first (A) all-cause readmission and (B) AECOPD-related readmission within 60 days postdischarge for DPI and pMDI cohorts.

Abbreviations: AECOPD, acute exacerbation of COPD; DPI, dry powder inhaler; ICS, inhaled corticosteroid; LABA, long-acting β₂-agonist; pMDI, pressurized metered-dose inhaler.

Table 4 All-cause and AECOPD readmissions

	Bivariate results					Multivariatea results (DPI vs pMDI)
	DPI		pMDI		P-value	OR	Lower 95% CL	Upper 95% CL	P-value
	n/mean	%/SD	n/mean	%/SD
All-cause readmission within 30 days (n, %)	276	14.1%	139	12.8%	0.32	0.88	0.70	1.11	0.28
Days to the first all-cause readmission within 30 days (mean, SD, median)	8.0	9.3	8.9	9.2	0.35
All-cause readmission within 60 days (n, %)	358	18.3%	188	17.3%	0.51	0.91	0.74	1.12	0.38
Days to the first all-cause readmission within 60 days (mean, SD, median)	16.1	17.6	18.5	18.7	0.14
AECOPD readmission within 30 days (n, %)	109	5.6%	46	4.2%	0.11	0.72	0.50	1.04	0.08
Days to the first AECOPD readmission within 30 days (mean, SD, median)	5.0	7.6	8.2	9.5	0.028
AECOPD readmission within 60 days (n, %)	140	7.1%	61	5.6%	0.10	0.72	0.52	0.99	0.045
Days to the first AECOPD readmission within 60 days (mean, SD, median)	13.2	17.3	17.0	18.1	0.16

Note:

a Logistic regression models.

Abbreviations: AECOPD, acute exacerbation of COPD; CL, confidence limit; DPI, dry powder inhaler; pMDI, pressurized metered-dose inhaler.

Figure 3 Predicted mean and 95% CIs of (A) all-cause and (B) COPD-related total health care costs (PPPM) in the 90-day postindex period.

Note: All costs are presented in USD.
Abbreviations: DPI, dry powder inhaler; pMDI, pressurized metered-dose inhaler; PPPM, per person per month.