Cost-comparison of two trabecular micro-bypass stents versus selective laser trabeculoplasty or medications only for intraocular pressure control for patients with open-angle glaucoma

Figures & data

Figure 1. Treatment transitions. Transitions between treatments were modeled annually and were only permitted in the directions of the arrows. Rectangular blue boxes represent initiating treatments considered in year 0. Grey ovals represent downstream treatments considered in years 1–5. Blue arrows represent the first transitions after the first model cycle (in year 0), and grey arrows represent downstream treatment transitions in subsequent cycles (years 1–5). SLT: selective laser trabeculoplasty.

Table 1. Percentage of uncontrolled OAG patients receiving therapies.

Table 2. Use of concurrent and standalone medications.

Number of concurrent medications^a	Types of medications^b^,^c
0	N/A
1	Prostaglandin
2	75% prostaglandin and beta-blocker; or 25% prostaglandin and (CAI/AAA)^d
3	prostaglandin and beta-blocker and AAA/CAI^e
4	prostaglandin and 2 meds combo^f and (CAI or AAA)

SLT: selective laser trabeculoplasty; CAI: carbonic anhydrase inhibitors; AAA: alpha-2 agonists.

^a During each cycle, a patient being treated with medications-only was expected to receive 2–4 medications, and a patient being treated with iStents, SLT, or filtering surgery treatments was expected to receive 0–4 medications.

^b Prostaglandins = bimatoprost, travoprost, or latanoprost.

^c Beta-blockers = timolol maleate.

^d brimonidine tartrate/brinzolamide.

^e brimonidine tartrate/Dorzolamide HCl.

^f Combination AAA plus beta-blocker or Combination CAI plus beta-blocker.

Table 3. Inputs.

Input	Basecase value	Source	Sensitivity analysis
			Low	High	Reason
Treatment costs
Medications^a
1 medication	$495.01	2016 RED BOOK, 2014 IMS prescriptions data^11–13	$371.26	$618.76	±25%
2 medications	$960.66	2016 RED BOOK, 2014 IMS prescriptions data^11–13	$720.50	$1,200.83	±25%
3 medications	$1,020.04	2016 RED BOOK, 2014 IMS prescriptions data^11–13	$765.03	$1,275.05	±25%
4 medications	$2,086.41	2016 RED BOOK, 2014 IMS prescriptions data^11–13	$1,564.81	$2,608.01	±25%
Procedures^a
iStent procedure	$2,711.27	OPPS LDS 2016, manufacturer sales data on file	$2,033.45	$3,389.09	±25%
SLT	$396.39	OPPS LDS 2016	$297.29	$495.49	±25%
Filtering surgery	$3,783.32	OPPS LDS 2016, 2013 CMS claims data	$2,837.49	$4,729.15	±25%
Complications^b
1st following year
iStent procedure	$0.00	Fea et al.^14; Vold et al.^16	$0.00	$510.69	$0, $(50% surgery complication)
SLT	$0.00	Realini et al.^15	$0.00	$510.69	$0, $(50% surgery complication)
Filtering surgery	$1021.38	2013 CMS claims data	$766.04	$1,276.73	±25%
All other subsequent years
iStent procedure	$0.00	Fea et al.^14; Vold et al.^16	$0.00	$181.69	$0, $(50% surgery complication)
SLT	$0.00	Realini et al.^15	$0.00	$181.69	$0, $(50% surgery complication)
Filtering surgery	$363.37	2013 CMS claims data	$272.53	$454.21	±25%
Annual time preference discount rate	3.0%		1.0%	5.0%	ISPOR guidelines^18

SLT: selective laser trabeculoplasty; OPPS LDS: Outpatient Prospective Payment System Limited Data Set; CMS: Centers for Medicare and Medicaid Services; ISPOR: International Society for Pharmacoeconomics and Outcomes Research.

^a Applied once in the cycle during which treatment is received.

^b Annual costs applied during cycles subsequent to receiving treatment.

Figure 2. Cumulative costs of treatments over 5 years. SLT: selective laser trabeculoplasty.

Table 4. Annual marginal costs.

Initial treatment	Year						Average per follow-up year (1–5)
	0	1	2	3	4	5
Medications only	$996	$1,065	$1,055	$1,044	$1,033	$1,022	$1,044
SLT	$842	$691	$740	$783	$814	$860	$777
iStent procedure	$2,810	$217	$290	$343	$358	$401	$322

SLT: selective laser trabeculoplasty.

Figure 3. Tornado diagram. (a) Incremental 5-year costs difference with the iStent procedure compared to SLT. (b) Incremental 5-year costs difference with the iStent procedure compared to medications only. SLT, selective laser trabeculoplasty. Dotted vertical line represents the base case result.

Table 5. Inputs uncertainty most influencing 5-year cumulative cost outcomes.

Influential input order	Cumulative costs by initial treatment arm			Cumulative cost difference
	iStent procedure	SLT	Medications-only	iStent procedure vs SLT	iStent procedure vs medications only
1	Cost of the iStent procedure	Cost of medications	Cost of medications	Cost of the iStent procedure	Cost of medications
2	Cost of medications	Probability of downstream procedures in the SLT arm	Time preference discount	Cost of medications	Cost of the iStent procedure
3	Probability of downstream procedures in the iStent procedure arm	Time preference discount	Probability of downstream procedure in the medications-only arm	Probability of downstream procedures in the SLT arm	Probability of downstream procedures in the iStent procedure arm
4	Cost of iStent procedure complications	Cost of SLT	Cost of filtering surgery	Probability of downstream procedures in the iStent procedure arm	Cost of iStent procedure complications
5	Time preference discount	Cost of SLT complications	Cost of SLT complications	Cost of iStent procedure complications	Time preference discount

SLT: selective laser trabeculoplasty.

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