The Cost-effectiveness of the Argus II Retinal Prosthesis in Retinitis Pigmentosa Patients

Anil Vaidya; Elio Borgonovi; Rod S Taylor; José-Alain Sahel; Stanislao Rizzo; Paulo Eduardo Stanga; Amit Kukreja; Peter Walter

Disclosures

BMC Ophthalmol. 2014;14(49)

Results

Base Case Results

Argus II Retinal Prosthesis fitted patients incurred a discounted incremental cost of 42,455 Euros in comparison to the patient given 'CAU' over the 25 years of time. Progressive improvement in the visual acuity of the Argus II fitted patients resulted in gain of 2.91 incremental QALYs (discounted). Incremental cost-effectiveness ratio for Argus II was calculated to be 14,603 Euros per QALY. Base case deterministic results are presented in Table 2.

Sensitivity Analysis Results

Probabilistic Sensitivity Analysis (PSA) showed that the cost-effectiveness of Argus II was robust to change to all key parameters within their plausible range. 1000 Monte Carlo simulations resulted in a mean incremental cost for Argus II of 42,018 Euros and mean incremental QALYs of 2.90. The Probabilistic Incremental Cost-Effectiveness Ratio (ICER) was estimated to be 14,482 Euros per QALY. The mean of incremental costs and QALY values derived from probabilistic simulations are presented in Table 2. The probabilistic model outputs are graphically illustrated in the form of incremental cost-effectiveness planes in Figure 2. In Figure 3 the CEACs show that Argus II becomes 100% cost effective at a WTP of 31000 Euros.

(Enlarge Image)

Figure 2.

Incremental cost-effectiveness plane.

(Enlarge Image)

Figure 3.

Cost-effectiveness acceptability curves (CEACs).

Scenario Analysis Results

When the model was run for 20 years and 10 years Argus II fitted patients yielded 2.49 and 1.35 discounted incremental QALYs, for a discounted incremental cost of 49,128 and 67,140 Euros respectively. When costs across all health states were constant then the deterministic Incremental Cost-effectiveness Ratios (ICER) for 25 years, 20 years and 10 years' time horizons were 31,890, 33,842 and 68,096 Euros per QALY, respectively. Probabilistic simulations also calculated ICER values very similar to the deterministic ones. The detailed results of the scenario analyses are presented in Table 3 and Table 4.

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Table 1. Model parameters
Name	Description	Deterministic value	Probabilistic components						Source
			Distribution	Range		Gamma	Alpha1	Alpha 2
			Distribution	Min	Max	Gamma	Alpha1	Alpha 2
cDR	Cost discount rate	0.035	Fixed						Pharmaco economic guidelines (NICE)
oDR	Outcome discount rate	0.035	Fixed						Pharmaco economic guidelines (NICE)
cArgus II	Costs of device + implantation	90800	BETA Pert	68100	113500	8	5	5	Second Sight
cRP	Annual health care costs incurred on RP patients	11789	BETA Pert	8841	14736	8	5	5	Frick et al. [14]
cVA+	Annual health care costs incurred on RP patients with VA+	9431	BETA Pert	7073	11789	8	5	5	Frick et al. [14] + assumption
cVA++	Annual health care costs incurred on RP patients with VA++	8252	BETA Pert	6189	10315	8	5	5	Frick et al. [14]+ assumption
cVA+++	Annual health care costs incurred on RP patients with VA+++	7073	BETA Pert	5305	8841	8	5	5	Frick et al. [14] + assumption
cSAE	Cost of management of Serious Adverse Event	1000	BETA Pert	750	1250	8	5	5	Expert opinion
cExplant	Cost of Explantation	2000	BETA Pert	1500	2500	8	5	5	Humayun et al. [9]/Second sight
cOthers	Annual other costs for Argus II patients (e.g. Upgrades etc.)	300	BETA Pert	225	375	8	5	5	Humayun et al. [9]/Second sight
pVA+	Argus II patient's annual probability of getting VA+	0.74	BETA Pert	0.554	0.924	8	5	5	Humayun et al. [9]/Second Sight
pVA++	Argus II patient's annual probability of getting VA++	0.21	BETA Pert	0.154	0.257	8	5	5	Humayun et al. [9]/Second sight
pVA+++	Argus II patient's annual probability of getting VA++	0.04	BETA Pert	0.029	0.049	8	5	5	Humayun et al. [9]/Second sight
pSAE	Probability of Serious Adverse Event in Argus II patients in first year	0.3	BETA Pert	0.225	0.375	8	5	5	Humayun et al. [9]/Second Sight
pExplant	Argus II patient's annual probability of device explantation	0.02	BETA Pert	0.013	0.021	8	5	5	Humayun et al. [9]/Second Sight
uRP	Utility value in RP patients	0.26	BETA Pert	0.195	0.325	8	5	5	Brown et al. [18]
uVA+	Utility value in RP patients with VA+	0.35	BETA Pert	0.263	0.438	8	5	5	Brown et al. [18]
uVA++	Utility value in RP patients with VA++	0.52	BETA Pert	0.39	0.65	8	5	5	Brown et al. [18]
uVA+++	Utility value in RP patients with VA+++	0.54	BETA Pert	0.405	0.675	8	5	5	Brown et al. [18]
uSAE	(dis) utility value in patients with Serious Adverse Events	0.16	BETA Pert	0.12	0.2	8	5	5	Schiffman et al. [19]
uExplant	Utility value in patients post Argus II explantation	0.26	BETA Pert	0.195	0.325	8	5	5	Assumption

Table 2. Base case results
Intervention	Deterministic		Probabilistic
Intervention	Disc costs	Disc QALYs	Disc costs	Disc QALYs
Argus II	€ 243,549	7.34	243,511	7.35
CAU	€ 201,094	4.44	201,493	4.44
Increment	€ 42,455	2.91	42,018	2.90
ICERs		€ 14,603		€ 14,482

Table 3. Scenario analysis
Time horizon 20 years
Intervention	Deterministic		Probabilistic Mean of 1000 simulations
Intervention	Disc costs	Disc QALYs	Disc costs	Disc QALYs
Argus II	€ 222,536	6.31	222,482	6.32
CAU	€ 173,408	3.82	173,752	3.83
Increment	€ 49,128	2.49	48,729	2.49
ICERs		19,744		19,602
Time horozon 10 years
Intervention	Deterministic		Probabilistic Mean of 1000 simulations
Intervention	Disc costs	Disc QALYs	Disc costs	Disc QALYs
Argus II	€ 168,613	3.59	168,560	3.59
CAU	€ 101,473	2.24	101,674	2.24
Increment	€ 67,140	1.35	66,886	1.35
ICERs		€ 49,769		€ 49,475

Table 4. Scenario analysis
Scenario analysis with constant costs for all Markov states (no cost reduction)
Time horizon 25 years
Intervention	Deterministic		Probabilistic Mean of 1000 simulations
Intervention	Disc costs	Disc QALYs	Disc costs	Disc QALYs
Argus II	293,807	7.34	294,083	7.35
CAU	201,094	4.44	200,995	4.43
Increment	92,712	2.91	93,088	2.93
ICERs		31,890		31,822
Time horizon 20 years
Intervention	Deterministic		Probabilistic Mean of 1000 simulations
Intervention	Disc costs	Disc QALYs	Disc costs	Disc QALYs
Argus II	265,906	6.31	266,216	6.32
CAU	173,408	3.82	173,323	3.82
Increment	92,498	2.49	92,893	2.50
ICERs		37,174		37,117
Time horizon 10 years
Intervention	Deterministic		Probabilistic Mean of 1000 simulations
Intervention	Disc costs	Disc QALYs	Disc costs	Disc QALYs
Argus II	193,336	3.59	193,730	3.59
CAU	101,473	2.24	101,423	2.23
Increment	91,864	1.35	92,307	1.36
ICERs		68,096		68,089