Comparative cost-effectiveness of a fluticasone-propionate/salmeterol combination versus anticholinergics as initial maintenance therapy for chronic obstructive pulmonary disease

Figures & data

Table 1 Demographic and clinical characteristics of study population (“risk population”)

	FSC (n = 16,684)a	Ipratropium (n = 14,449)a	Tiotropium (n = 12,659)a
Age, mean (SD)	62.8 (12.0)	65.2 (12.6)b	64.5 (11.3)b
Female	9127 (54.7)	7143 (49.4)b	5862 (46.3)b
≥12 months follow-up	12,595 (75.5)	10,617 (73.5)b	9126 (72.1)b
Selected comorbid conditions:
Asthma	4077 (24.4)	1951 (13.5)b	1510 (11.9)b
Congestive heart failure	1850 (11.1)	2967 (20.5)b	1945 (15.4)b
Depression	1153 (6.9)	1184 (8.2)b	848 (6.7)
Hypertension (uncomplicated)	8098 (48.5)	7627 (52.8)b	6484 (51.2)b
COPD-related utilization in preindex period:
Outpatient visit	5173 (31.0)	4426 (30.6)	5401 (42.7)b
Outpatient visit with oral corticosteroid	509 (3.1)	669 (4.6)b	353 (2.8)
Outpatient visit with antibiotic	865 (5.2)	1030 (7.1)b	692 (5.5)
Emergency department visit	408 (2.4)	609 (4.2)	336 (2.7)
Hospitalization	811 (4.9)	1428 (9.9)b	895 (7.1)b
Emergency department visit or hospitalization	1184 (7.1)	1983 (13.7)b	1184 (9.4)b
Short-acting β-agonist	4178 (25.0)	2044 (14.1)b	2572 (20.3)b
Health care costs in preindex period, mean (SD):
Medical	993 (16,589)	2162 (12,722)b	1459 (12,439)b
Pharmacy	49 (165)	32 (135)b	33 (106)b
Total	1042 (16,589)	2193 (12,721)b	1492 (12,439)b

Notes:

a All figures are n (%) unless otherwise noted;

b P<0.05 for difference with FSC cohort.

Abbreviations: COPD, chronic obstructive pulmonary disease; FSC, fluticasone propionate/salmeterol combination.

Figure 1 Patient selection.

Table 2 Results from Cox proportional hazard analyses examining risk of COPD exacerbations between study cohorts (“risk population”)

COPD-related utilization	Ipratropiuma n = 14,449	Tiotropiuma n = 12,659
	Hazard ratio (95% confidence interval)b,c
Outpatient visit with oral corticosteroid	1.65 (1.41–1.94)	1.49 (1.26–1.76)
Outpatient visit with antibiotic	1.39 (1.23–1.57)	1.33 (1.17–1.51)
Emergency department visit	1.78 (1.59–2.00)	1.33 (1.17–1.51)
Hospitalization or emergency department visit	1.64 (1.50–1.79)	1.29 (1.17–1.41)

Notes:

a With reference to the FSC cohort;

b The postindex date period ranged from 3 to 12 months; follow-up began on day 30 following initiation of initial maintenance therapy;

c Adjusted for age, gender, treatment, and comorbidities and COPD-related health care utilization at baseline.

Abbreviations: COPD, chronic obstructive pulmonary disease; FSC, fluticasone propionate/salmeterol combination.

Figure 2 Time to any event^a Kaplan–Meier survival curve: Initial maintenance therapy with FSC, tiotropium, or ipratropium.^b,c

Notes: ^aAny COPD-related outpatient visit, emergency department visit or inpatient admission; ^bFollow-up period ranged from 3 to 12 months; ^cFor determining the survival function, follow-up began on day 30 following initiation of initial maintenance therapy.
Abbreviation: COPD, chronic obstructive pulmonary disease; FSC, fluticasone propionate/salmeterol combination.

Table 3 Unadjusted COPD-related health care utilization and costs associated with initial maintenance therapies in the one-year follow-up period (“cost population”)

	FSC (n = 12,595)	Ipratropium (n = 10,617)	P valuea	Tiotropium (n = 9126)	P valuea
COPD medication utilization
Medication possession ratio for primary initial maintenance therapy medication (mean, SD)	32% (28%)	22% (23%)	<0.001	41% (33%)	<0.001
Alternate maintenance therapy, n (%)
FSC	na	795 (7.5)	–	839 (9.2)	–
Ipratropium	713 (5.7)	na	–	461 (5.1)	<0.001
Tiotropium	956 (7.6)	790 (7.4)	<0.876	na	–
Any alternate maintenance therapy	1571 (12.5)	1367 (12.9)	0.560	1208 (13.2)	0.187
SABA prescription fills, mean (SD)	1.44 (2.90)	0.81 (2.45)	<0.001	1.48 (3.13)	0.4029
COPD-related health care utilization, n (%)
Hospitalization	446 (3.5)	651 (6.1)	<0.001	413 (4.5)	<0.001
Outpatient visit w/oral corticosteroid	261 (2.1)	354 (3.3)	<0.001	262 (2.9)	<0.001
Outpatient visit with antibiotic	490 (3.9)	617 (5.8)	<0.001	478 (5.2)	<0.001
Emergency department visit	450 (3.6)	778 (7.3)	<0.001	427 (4.7)	<0.001
Outpatient visit	3615 (28.7)	3788 (35.7)	<0.001	3661 (40.1)	<0.001
Hospitalization/emergency department visit	819 (6.5)	1284 (12.1)	<0.001	764 (8.4)	<0.001
COPD-related health care utilization, mean (SD)
Outpatient visit	0.76 (2.24)	1.28 (3.13)	<0.001	1.26 (3.14)	<0.001
Outpatient visit with oral corticosteroid	0.03 (0.27)	0.05 (0.33)	<0.001	0.04 (0.28)	0.0153
Outpatient visit with antibiotic	0.05 (0.32)	0.08 (0.40)	<0.001	0.07 (0.37)	<0.001
Emergency department visit	0.04 (0.28)	0.09 (0.37)	<0.001	0.06 (0.28)	0.0044
Hospitalization	0.04 (0.24)	0.08 (0.34)	<0.001	0.06 (0.29)	0.0011
Hospitalization/emergency department visit	0.09 (0.40)	0.17 (0.55)	<0.001	0.11 (0.44)	<0.001
COPD-related health care costs, mean (SD)
Medicalb	$1058 ($7545)	$2179 ($12,094)	<0.001	$1485 ($9489)	0.001
Pharmacyc	$960 ($1040)	$630 ($945)	<0.001	$968 ($949)	0.551
Total	$2018 ($7658)	$2809 ($12,219)	<0.001	$2453 ($9588)	0.001

Notes:

a For difference with FSC cohort;

b Medical costs include outpatient, emergency department, and inpatient care;

c Pharmacy costs include all outpatient prescription medication costs (includes cost of study medication as well as other COPD medications dispensed after the 60-day postindex date window).

Abbreviations: FSC, fluticasone propionate/salmeterol combination; na, not applicable; SABA, short-acting beta-agonist; SD, standard deviation; COPD, chronic obstructive pulmonary disease.

Table 4 Adjusted differences in COPD-related costs in the one-year follow-up period (“cost population”)a

COPD-related health care	Difference in adjusted costs relative to FSC, $US (95% CI)
	Ipratropium (n = 10,617)	Tiotropium (n = 9126)
Medicalb	1405 (1329,1490)	344 (288,401)
Pharmacyc	−358 (−369,−346)	14 (1,26)
Totald	773 (716,829)	339 (287,395)

Notes:

a Costs and odds ratios were adjusted for age, gender, treatment and other covariates;

b Medical costs include COPD-related outpatient, emergency department, and inpatient care;

c Pharmacy costs include all outpatient prescription medication costs (includes costs of study medication as well as other COPD medications dispensed after the 60-day postindex date window);

d Costs are not cumulative because individual models were used to predict each component. CI were generated by bootstrapping 1000 simulated samples.

Abbreviations: CI, confidence intervals; COPD, chronic obstructive pulmonary disease; FSC, fluticasone propionate/salmeterol combination.

Figure 3 Predicted (adjusted) 12-month COPD-related health care costs (in 2009 $US) associated with different initial maintenance therapies (data from the “cost population”).^a A) COPD-related health care costs; B) Breakdown of the medical component of COPD-related health care costs.

Note: ^aCosts were adjusted for age, gender, treatment, and comorbidities and COPD-related health care utilization at baseline. P-values are for differences between tiotropium and FSC, and between ipratropium and FSC.
Abbreviations: COPD, chronic obstructive pulmonary disease; FSC, fluticasone propionate/salmeterol combination.