Cost-Effectiveness of Peptide Enhanced Bone Graft i-Factor versus Use of Local Autologous Bone in Anterior Cervical Discectomy and Fusion Surgery

Figures & data

Figure 1 Markov model depicts patient’s health and work status at each follow-up period. Each node represents transition to health states associated with different costs and utility scores.

Table 1 Probability of Complications Depending on Preoperative Health Care Status

Parameters	Period	Value		Source
1. Health state before index operation		All
Mild	< 0 (Initial State)	1%		RCT
Moderate	< 0 (Initial State)	7%
Severe	< 0 (Initial State)	24%
Crippled	< 0 (Initial State)	40%
Bedbound	< 0 (Initial State)	29%
2. Probability of Complication (related Surgical or Device)
		Control	i-Factor	RCT
None	All Time	0.834	0.844
Minor	All Time	0.145	0.137
Major	All Time	0.021	0.019
3. Probability of Action Following Complication
		Control	i-Factor	RCT & recommended action for each recorded complication
Minor to Conservative Care	>1 (Postop +)	0.920	0.942
Major to Conservative Care	>1 (Postop +)	0.198	0.269
Minor to Surgery	>1 (Postop +)	0.080	0.058
Major to Surgery	>1 (Postop +)	0.802	0.731
3. Probability of Subsequent Surgeries
		Control	i-Factor	RCT
Revision	9M - 1YR	0.016	-
	1YR - 18M	0.007	-
	18M - 2YR	0.016	0.010
	2YR - 2YR +	0.009	0.010
Removal	9M - 1YR	-	-
	1YR - 18M	0.007	-
	18M - 2YR	-	-
	2YR - 2YR +	0.014	0.020
Reoperation	9M - 1YR	-	-
	1YR - 18M	-	-
	18M - 2YR	-	0.010
	2YR - 2YR +	0.007	-
Supplemental Fixation	9M - 1YR	-	0.010
	1YR - 18M	-	-
	18M - 2YR	-	0.020
	2YR - 2YR +	0.014	0.010
Other	9M - 1YR	0.008	0.010
	1YR - 18M	-	-
	18M - 2YR	0.031	0.020
	2YR - 2YR +	0.012	0.020

Table 2 Direct Surgical Costs

1 Ancillary Procedure	DRG/CPT	Medicare	Private
MRI Cervical Spine	72,141	$224.16	$1,101.00
CT Cervical Spine	72,125	$188.68	$191.00
Epidural steroid injection	62,320	$102.71	$117.00
Physical therapy	97,110	$81.01	$227.00
Office Visit	99,214	$51.90	$109.00
2 Index Operation
Facility fee	DRG 473	$13,102.90	$21,350.00
Outpatient Fee	APC 5115	$9,912.69	$16,151.84
Neck spine fusion below c2	22,551	$1,789.70	$1,951.00
Device	22,854	$352.46	$546.00
Insert spine fixation device	22,845	$768.71	$2,760.00
Structural allografts	20,931	$117.49	$125.00
Fluoroscopy	77,003	$99.83	$204.00
i-Factor	1cc; 2.5cc; 5cc		$575; $1226; $2090
3 Revision, removal, fixation, or reoperation of ACDF
Facility fee	DRG 472	$18,263.96	$29,759.48
	471	$34,294.86	$55,880.39
Exploration of Spinal Fusion	22,830	$851.24	$433.00
Removal Spine Fixation Device	22,855	$1,160.10	$1,890.28
Neck spine fusion below c2	22,551	$1,789.70	$1,951.00
Device	22,854	$352.46	$546.00
Insert spine fixation device	22,845	$768.71	$2,760.00
Structural allografts	20,931	$117.49	$125.00
Fluoroscopy	77,003	$99.83	$204.00

Table 3 Base Case Results with Medicare and Private Rates (Both Perspectives)

	Time Horizon	i-Factor		Control		∆Cost ^b	∆QALY^c	ICER ^d, $ per QALY
		Cost ^a	QALY	Cost	QALY
Health systems	90 Day	$32,283.00	0.1999	$32,203.00	0.1939	$80.00	0.006	$13,333.33
	1 Year	$46,029.00	0.7789	$46,997.00	0.7584	-$968.00	0.0205	Dominant
	2 Year (Base Case)	$55,706.00	1.424	$57,389.00	1.3856	-$1,683.00	0.0384	Dominant
	6 Year (Extrapolated)	$74,678.00	2.6458	$77,805.00	2.5641	-$3,127.00	0.0817	Dominant
	10 Year (Extrapolated)	$128,475.00	5.7838	$135,861.00	5.5599	-$7,386.00	0.2239	Dominant
Societal	90 Day	$35,374.00	0.1999	$35,423.00	0.1939	-$49.00	0.006	Dominant
	1 Year	$57,970.00	0.7789	$58,819.00	0.7584	-$849.00	0.0205	Dominant
	2 Year (Base Case)	$78,646.00	1.424	$80,307.00	1.3856	-$1,661.00	0.0384	Dominant
	6 Year (Extrapolated)	$117,494.00	2.6458	$120,959.00	2.5641	-$3,465.00	0.0817	Dominant
	10 Year (Extrapolated)	$222,178.00	5.7838	$230,822.00	5.5599	-$8,644.00	0.2239	Dominant

Notes: ^aIncludes P-15 cost in the initial surgery. ^b∆Cost = P-15 cost - Control cost. ^c∆QALY = P-15 QALY - Control QALY. ^dICER = ∆Cost/∆QALY; “Dominant” indicates that i-Factor costs less while yielding a higher QALY.

Table 4 Scenario Sensitivity Analyses: Cost-Effectiveness of P-15 vs Control in Alternative Scenarios

		Cost, per Patient (i-Factor)	QALY, per Patient	∆Cost^a	∆QALY^b	ICER^c	NMB^d
Alternative Surgical Settings	1 50% Medicare, 50% Privately Insured
	100% Inpatient (Base Case)	$55,706.00	1.424	-$1,683.00	0.0384	-$43,828.13	$3,603.00
	50/50 Inpat/Outpat	$51,567.00	1.424	-$1,683.00	0.0384	-$43,828.13	$3,603.00
	100% Outpatient	$47,428.00	1.424	-$1,683.00	0.0384	-$43,828.13	$3,603.00
Alternative Payment Compositions	2 All at Medicare Rates
	100% Inpatient	$42,644.00	1.424	-$1,128.00	0.0384	-$29,375.00	$3,048.00
	50/50 Inpat/Outpat	$39,594.00	1.424	-$1,128.00	0.0384	-$29,375.00	$3,048.00
	100% Outpatient	$36,543.00	1.424	-$1,128.00	0.0384	-$29,375.00	$3,048.00
	3 All at Private Insurer Rates
	100% Inpatient	$68,767.00	1.424	-$2,239.00	0.0384	-$58,307.29	$4,159.00
	50/50 Inpat/Outpat	$63,540.00	1.424	-$2,239.00	0.0384	-$58,307.29	$4,159.00
	100% Outpatient	$58,312.00	1.424	-$2,239.00	0.0384	-$58,307.29	$4,159.00

Notes: ^a∆Cost = i-Factor cost - Control Cost. ^b∆QALY = i-Factor QALY - Control QALY. ^cICER = ∆Cost/∆QALY; “Dominant” indicates that i-Factor costs less while yielding a higher QALY. ^dNMB = ∆QALY *WTP threshold ($100,000) - ∆Cost. Same value as top line values in the section.

Figure 2 (A) Cost-effectiveness scatter plot representing 5,000 simulated iteration of input parameter variations. The resultant difference in increments of cost vs effectiveness is illustrated. Simulation points below the WTP line indicate cost-effectiveness. (B) Cost-effectiveness acceptability curves created based on the sensitivity analysis scatter plot. Percentages of iterations achieving cost-effectiveness are plotted for either group based on willingness-to-pay thresholds.

Abbreviation: WTP, willingness-to-pay.