A longitudinal, retrospective cohort study on the impact of roflumilast on exacerbations and economic burden among chronic obstructive pulmonary disease patients in the real world

Figures & data

Figure 1 Study design and cohort selection.

Figure 2 Flow chart of patient selection.

Abbreviation: ICD-9, International Classification of Diseases, Ninth Revision.

Table 1 Demographic and clinical characteristics at baseline

Variable	Roflumilast (n=710)	Non-roflumilast (n=13,501)	P-value
Age at index date (years), mean ± SD	63.2±9.4	63.3±10.4	0.78
Male, n (%)	371 (52)	7,065 (52)	0.97
Charlson comorbidity score, mean ± SD	1.0±1.5	1.0±1.5	0.43
Comorbid conditions, n (%)a
Diabetes	165 (23)	2,908 (22)	0.28
Congestive heart failure	107 (15)	1,549 (11)	0.004
Cerebrovascular disease	79 (11)	1,280 (9)	0.15
Peripheral vascular disease	66 (9)	1,153 (9)	0.48
Chronic renal failure	48 (7)	819 (6)	0.45
Malignancy (any)	39 (5)	999 (7)	0.06
Monthly rate of exacerbations at baseline period (PPPM)
Moderate or severe	0.1109±0.1331	0.0529±0.0903	<0.001
Moderate	0.0883±0.1117	0.0435±0.0826	<0.001
Severe	0.0227±0.0589	0.0094±0.0315	<0.001
Resource utilization during baseline period
Number of COPD medications, mean ± SD	3.2±2.1	2.6±2.1	<0.001
Days receiving COPD medications, mean ± SD	188±133	166±143	<0.001
Number of ED visits, mean ± SD	0.5±2.0	0.3±1.0	<0.001
At least one hospitalization, n (%)	558 (79)	9,697 (72)	<0.001

Note:

a Only those identified in $5% of patients were reported.

Abbreviations: ED, emergency department; SD, standard deviation; baseline, 12-month preindex period; PPPM, per patient per month.

Figure 3 Monthly chronic obstructive pulmonary disease exacerbations: (A) total exacerbations, (B) severe exacerbations, (C) moderate exacerbations.

Notes: Baseline refers to monthly exacerbation rate during the 12-month preindex period; follow-up refers to monthly exacerbation rate during the 3-month follow-up period.

Table 2 Monthly health care resource utilization

Health care resource utilization	Roflumilast (n=710)	Non-roflumilast (n=13,501)	P-value
Office visits
Baseline period, mean ± SD	0.370±0.575	0.316±0.559	<0.001
Follow-up period, mean ± SD	0.451±0.973	0.438±0.978	0.83
Change from baseline, mean ± SD	0.081±0.938	0.122±0.889	0.01
Emergency department visits
Baseline period, mean ± SD	0.042±0.166	0.028±0.082	0.06
Follow-up period, mean ± SD	0.051±0.197	0.035±0.154	0.02
Change from baseline, mean ± SD	0.009±0.233	0.007±0.147	0.80
Inpatient hospitalizations
Baseline period, mean ± SD	0.041±0.085	0.027±0.061	<0.001
Follow-up period, mean ± SD	0.043±0.145	0.032±0.121	0.03
Change from baseline, mean ± SD	0.002±0.152	0.005±0.123	0.02

Note: The result data represent average resource use per patient per month.

Abbreviations: Baseline, 12-month preindex period; SD, standard deviation.

Table 3 Monthly total health care costs ($)

Total costs	Roflumilast (n=710)	Non-roflumilast (n=13,501)	P-value
Baseline period, mean ± SD	2,420±3,862	1,950±3,225	<0.001
Follow-up period, mean ± SD	2,851±5,327	2,472±6,252	<0.001
Change from baseline, mean ± SD	432±5,244	522±6,047	0.34

Note: The result data represent average cost per patient per month.

Abbreviations: Baseline, 12-month preindex period; SD, standard deviation.

Table S1 Monthly total health care costs and cost by component ($)

Cost variable	Non-roflumilast (n=13,501)	Roflumilast (n=710)	P-value
Baseline costs
Total cost, mean ± SD	1,950±3,225	2,420±3,862	<0.001
Inpatient costs, mean ± SD	810±2,295	1,030±2,417	<0.001
Outpatient costs, mean ± SD	561±1,332	715±1,964	<0.001
ER costs, mean ± SD	22±133	33±224	0.09
COPD drug costs, mean ± SD	259±518	294±412	<0.001
Follow-up costs
Total cost, mean ± SD	2,472±6,252	2,851±5,327	<0.001
Inpatient costs, mean ± SD	1,055±5,219	1,084±2,766	<0.001
Outpatient costs, mean ± SD	720±2,148	1,049±3,851	<0.001
ER costs, mean ± SD	25±183	42±262	0.014
COPD drug costs, mean ± SD	234±521	241±373	0.011

Notes: The result data represent average cost per patient per month. The total cost is more than the sum of inpatient, outpatient, ER, and COPD drug costs because there are other types of cost components not shown in this table.

Abbreviations: Baseline, 12-month preindex period; COPD, chronic obstructive pulmonary disease; SD, standard deviation; ER, emergency room.