National and regional dose escalation and cost of tumor necrosis factor blocker therapy in biologic-naïve rheumatoid arthritis patients in US health plans

Figures & data

Table 1. Characteristics (nationally and regionally) among patients with RA who initiated TNF-blocker therapy and remained persistent for at least 12 months.

Characteristic	Etanercept (n = 1420)	Infliximab (n = 454)	Adalimumab (n = 874)	ETN vs INF p-value	ETN vs ADA p-value
Age, years, mean (SD)
National (all patients)	49.9 (9.8)	51.2 (9.2)	50.3 (9.9)	0.02	0.23
Regional (range)	48.8 (10.1)–50.6 (9.4)	49.6 (10.3)–51.8 (9.1)	48.9 (11.0)–50.7 (10.5)	NA	NA
Male, %
National	25.2	22.0	25.5	0.17	0.87
Regional	18.8–28.3	18.7–24.0	23.1–29.4	NA	NA
Geographic region, %				0.0005	<0.0001
Northeast	21.7	20.0	18.3
Midwest	39.6	34.1	39.5
South	24.0	33.9	34.7
West	14.7	11.9	7.6
Health plan type, %
Capitated (HMO)
National	22.8	20.3	21.8	0.27	0.62
Regional	15.3–28.1	13.6–27.7	14.5–29.3	NA	NA
Non-capitated
National	77.2	79.7	78.2	NA	NA
Regional	71.9–84.7	72.3–86.4	70.7–85.5	NA	NA
Payer type, %
Commercial
National	88.5	89.6	86.5	0.78	0.51
Regional	80.5–93.6	87.0–92.9	77.5–91.3	NA	NA
Medicaid
National	1.3	1.3	1.5	NA	NA
Regional	0–5.7	0–5.6	0–16.7	NA	NA
Self-insured
National	8.9	7.5	10.8	NA	NA
Regional	1.9–18.2	3.7–12.3	4.6–20.0	NA	NA
Other/unknown
National	1.3	1.5	1.3	NA	NA
Regional	0.9–2.9	0–4.4	0–2.5	NA	NA
Quan-Charlson Comorbidity Index, mean (SD)
National	1.39 (0.79)	1.50 (1.00)	1.39 (0.76)	0.09	0.90
Regional	1.32 (0.67)–1.43 (0.87)	1.45 (0.76)–1.64 (1.45)	1.32 (0.64)–1.54 (0.92)	NA	NA
Pre-index healthcare costs, US$, median
National	2946	3102	2868	0.05	0.39
Regional	2629–3139	2766–3467	2643–3070	NA	NA
Pre-index concomitant medication use, %
Methotrexate
National	80.6	76.9	82.3	0.09	0.31
Regional	76.0–85.2	71.4–80.6	81.5–83.8	NA	NA
NSAIDs
National	80.8	74.4	80.4	0.004	0.84
Regional	78.6–84.1	65.9–77.9	71.2–86.2	NA	NA
Analgesics
National	81.6	74.2	80.8	0.0006	0.62
Regional	75.0–88.0	62.6–78.1	78.8–83.3	NA	NA

ETN, etanercept; INF, infliximab; ADA, adalimumab; NSAIDs, non-steroidal anti-inflammatory drugs; NA, not applicable.

Figure 1. Regional proportion and magnitude of dose escalation using the average weekly dose method among RA biologic-naïve patients persistent on TNF-blocker therapy for 12 months.

Table 2. National proportion and magnitude of dose escalation among RA biologic-naïve patients persistent on TNF-blocker therapy for 12 months for each dose escalation method.

Dose escalation method	Etanercept (n = 1420)	Infliximab (n = 454)	Adalimumab (n = 874)	ETN vs INF p-value	ETN vs ADA p-value
Average weekly dose method
% of patients with dose escalation  (average weekly dose > recommended dose)	3.9	69.6	21.4	<0.0001	<0.0001
% of patients with 130% above index dose	0.5	36.1	9.0	<0.0001	<0.0001
Average ending dispensed dose
% of patients with dose escalation	1.1	63.0	10.6	<0.0001	<0.0001
Starting dose, mg	50	55	20
Ending dose, mg	93	94	40
Magnitude of dose escalation, %	86.7	75.1	100.0
Average dose after maintenance dose
% of patients with dose escalation	2.8	69.6	15.7	<0.0001	<0.0001
Maintenance dose, mg	50	56	20
Average dose after maintenance dose, mg	58	80	29
Magnitude of dose escalation, %	15.5	44.9	44.9

ETN, etanercept; INF, infliximab; ADA, adalimumab.

Figure 2. Regional proportion and magnitude of dose escalation using the average ending dispensed dose method among RA biologic-naïve patients persistent on TNF-blocker therapy for 12 months.

Figure 3. Regional proportion and magnitude of dose escalation using the average dose after maintenance dose method among RA biologic-naïve patients persistent on TNF-blocker therapy for 12 months.

Table 3. Cost of TNF-blocker therapy per treated RA patient.

	Etanercept (n = 1420)	Infliximab (n = 454)	Adalimumab (n = 874)
Total annual dose, mg, mean (SD)	2176 (390)	3383 (1073)	1027 (237)
Cost per treated patient without administration costs,^a US$	19,690	24,030	23,020
Cost per treated patient including administration-related costs,^b US$	19,710	25,520	23,040

^aTotal annual dose, wholesale acquisition cost (WAC); WAC prices as of September 8, 2011, p < 0.0001 for comparison between etanercept and adalimumab and between etanercept and infliximab. ^bAdministration-related costs based on 2011 Medicare Physician Fee Schedule as 2-h infusion per administration of infliximab (total number of infliximab infusions was 3826, 8.4 per patient) and one administration in office and remainder self-administered at home for etanercept and adalimumab.