Cost effectiveness of adding clostridial collagenase ointment to selective debridement in individuals with stage IV pressure ulcers

Figures & data

Table 1. Initial epithelialization and mortality probabilities.

	Epithelialization probability		Mortality probability
Cycle	CCO	Non-CCO	CCO	Non-CCO
1	0.006	0.006	0.0126	0.0103
2	0.021	0	0.0126	0.0103
3	0.019	0.019	0.0126	0.0103
4	0.021	0.034	0.0126	0.0103
5	0.053	0.009	0.0126	0.0103
6	0.054	0.026	0.0126	0.0103
7	0.055	0.006	0.0126	0.0103
8	0.056	0	0.0126	0.0103
9	0.019	0.036	0.0126	0.0103
10	0.063	0.024	0.0126	0.0103
11	0.07	0.019	0.0126	0.0103
12	0.061	0.01	0.0126	0.0103
13	0.052	0.034	0.0126	0.0103
14	0.115	0.013	0.0126	0.0103
15	0.093	0.027	0.0126	0.0103
16	0.03	0.031	0.0126	0.0103
17	0.032	0	0.0126	0.0103
18	0	0.018	0.0126	0.0103
19	0	0	0.0126	0.0103
20	0.045	0.043	0.0126	0.0103
21	0.05	0	0.0126	0.0103
22	0.056	0	0.0126	0.0103
23	0	0.027	0.0126	0.0103
24	0.071	0	0.0126	0.0103
25	0	0	0.0126	0.0103
26	0	0	0.0126	0.0103

CCO: clostridial collagenase ointment; non-CCO: selective debridement alone.

Figure 1. Epithelialization rates of stage IV pressure ulcers for clostridial collagenase ointment (CCO) added to selective debridement and selective debridement alone (non-CCO) in 4-week cycles.

Table 2. Classification of pressure ulcer location to cost unit categories.

Location	CCO (%)	Non-CCO (%)	Tracking to cost categories
(1) Sacrum/back	20.2	28.6	Offloading: group 2 low-air-loss mattress; pillows/body wedges; surgical; CPT codes 15931/15936/15734
(2) Buttocks (ischium)	22.3	27.7	Offloading: group 2 low-air-loss mattress; pillows/body wedges; surgical; CPT codes 15940/15946/15734
(3) Hip/thigh (trochanter)	12.5	8.6	Offloading: group 2 low-air-loss mattress; pillows/body wedges; pillows/body wedges;surgical; CPT codes 15950/15956/15734
(4) Heel/ankle	26.6	16.1	Offloading: heel protector
(5) Foot (no heel/ankle)	10.4	10.1	Offloading: Heelift traction boot or equivalent
(6) Other	8.0	8.9	—

CCO: clostridial collagenase ointment; CPT: current procedural terminology; non-CCO: selective debridement alone.

Table 3. Unit costs (US dollars).

Category	Item	CPT/HCPCS code	Medicare 2015 allowable charges (Medicare pays 80%, patient pays 20%)
Initial clinic visit^a^,^b	(a) Physician, evaluation	G0463	77.59
	(b) Facility	G0463	96.25
	(c) Physician, debridement	11042	63.29
	(d) Facility, debridement	11042	283.14
	(d) Facility, debridement with CCO	97602	146.14
Established clinic visit^a^,^b^,^c	(e) Physician, evaluation	G0463	51.13
	(f) Facility	G0463	96.25
	(g) Physician, debridement	97597	24.31
	(h) Facility, debridement	97597	146.14
	(i) Facility, debridement with CCO	97602	146.14
Offloading	(j) Roho high profile cushion or equivalent^d	E2625 NU mod	469.58
	(k) Group 2 low-air-loss mattress^e	E0277 RR mod	663.22
	(l) Heel protector^f	E0191 NU mod	10.52
	(m) Heelift traction boot or equivalent^g	E0945 mod NU	46.61
	(n) Pillows (2) and body wedges (2)^h	N/A (lowest commercial cost)	133.00

^a A clinic is a hospital-based outpatient wound care department.

^b The clinic visit included everything except debridement. Level 3 complexity was assumed for evaluation and management at all visits. Only 97,602 had a facility charge associated with it, and no other kind of debridement codes were billed with it.

^c If any debridement was performed at an established clinic visit, separate billing for evaluation and management charges was not permitted.

^d For wheelchair-bound patients having pressure ulcers located on the sacrum, back, buttocks, ischium, or hips.

^e For patients with pressure ulcers located on the sacrum, back, buttocks, ischium, or hips; cost was per month.

^f For patients with heel or ankle pressure ulcers; cost was every 12 weeks.

^g For patients with foot pressure ulcers; new unit every 26 weeks.

^h For patients with pus located on sacrum, buttocks, ischium, or hips.

CPT: Current Procedural Terminology; HCPCS: Healthcare Common Procedure Coding System; mod: modifier; NU: item was a new purchase; RR: item was rented.

Table 4. Four-week cycle costs^a (US dollars) for each intervention.

Cycle number	CCO	Non-CCO
1	1,033.91	1,376.62
2, 3, 5, 6, 8, 9, 11, 12	764.40	892.01
4, 10	767.20	893.70
7, 13	772.05	898.41
14, 15, 17, 18, 20, 21, 23, 24, 26	742.14	866.03
16, 22	744.85	867.67
19, 25	749.56	872.24

^a Costs were not discounted in cycles 1–13 and were discounted at 3% in cycles 14–26²⁴.

CCO: clostridial collagenase ointment; non-CCO: selective debridement alone.

Table 5. Unit costs (US dollars) associated with surgical wound closure.

Item	CPT/HCPCS Code	Medicare 2015 allowable charges^a (Medicare pays 80%, patient pays 20%)
Excision, sacral pressure ulcer, primary suture (sacrum/back)	15931	704.37 + 1,824.31
Excision, ischial pressure ulcer, primary suture (buttocks)	15940	716.52 + 1,824.31
Excision, trochanteric pressure ulcer, primary suture (thigh/hip)	15950	604.61 + 1,824.31
Excision, sacral pressure ulcer, flap prep (sacrum/back)	15936	909.60 + 1,407.42
Excision, ischial pressure ulcer, flap prep (buttocks)	15946	1,674.75 + 2,301.54
Excision, trochanteric pressure ulcer, flap prep (thigh/hip)	15956	1,178.12 + 1,407.42
Muscle, myocutaneous, or fasciocutaneous flap (trunk)	15734	1,355.82 + 2,301.54

^a Costs are national averages of Medicare allowable charges for the first half of 2015 (physician + facility charges)¹⁵.

CPT: Current Procedural Terminology; HCPCS: Healthcare Common Procedure Coding System.

Table 6. Variables used in sensitivity analysis.

Variable	Rationale	Basis	Values	Limitations
(1) Location proportions^a	Costs associated with pressure ulcer epithelialization depend on location of the pressure ulcer; non-CCO group had a higher proportion of sacral, ischial, and hip pressure ulcers	Set proportions equal in both groups, with 20% each for locations 1–3, 20% for location 4, and 10% each for locations 5 and 6^b	Use CCO 4-week healing rates, but set non-CCO healing rates at 0.75 of these values	Some uncertainty owing to small groups in datasets
(2) Epithelialization rates	Differences in epithelialization rates affect time to wound closure	Use proportions as set forth in location proportions analysis	Use non-CCO epithelialization rates of 0.65 and 0.85 of CCO 4-week epithelialization rates	Some uncertainty owing to small groups in datasets
(3) CCO application rates^c	More applications do increase epithelialization rates slightly	Increase 4-week application rates by 100%	Increase all 4-week epithelialization rates by 1.15	Difficult to estimate increased epithelialization rate
(4) Selective debridement	Deeper levels of debridement are more likely for initial visit and more costly	All patients get an initial visit, with 50% getting a 11043 debridement and 50% getting an 11044 debridement; CCO group patients get their first CCO application at second visit	11043: $159.82 (physician), $283.14 (facility) 11044: $238.84 (physician), $826.58 (facility)	Levels of debridement that occur in practice at first visit depend on many factors; for example, a few patients might need to be hospitalized
(5) Visit costs	Stage IV patients require higher levels of complexity for initial visit	Use G0463, level 5 for all patients	Physician: $170.55 Facility: $96.25	For non-Medicare insurance, facility charges will be much higher
(6) Offloading variations	More expensive options but not necessarily more effective	Increase all costs	50% increase	This is an arbitrary increase; some group 3 mattress options are much more expensive
(7) Surgical closure	30% of stage IV pressure ulcers require surgical closure	Add in costs at end of wound closure	$16,800 (×0.3)	Penalizes CCO over short horizon times
(8) Type of insurance	Type of insurance affects costs; Medicare is least expensive	Increase all unit costs	+20%	Actual increases will depend on type of insurance

^a Sub-group analysis suggested that epithelialization of pressure ulcers located on the sacrum, buttocks, or hips occurred more slowly than in other locations; so, based on these sub-group results, the non-CCO epithelialization rate was set at 0.75 of the CCO epithelialization rate. However, because this was an approximate estimate, the non-CCO epithelialization rate was varied, with 0.65 and 0.85 of CCO epithelialization rates (variable 2).

^b Locations: (1) sacrum/back, (2) buttocks (ischium), (3) hip/thigh (trochanter), (4) heel/ankle, (5) foot (no heel/ankle), and (6) other.

^c Increasing CCO application rates by 100% equated to 3.3 visits per 4 weeks, which is more than the 2.8 visits per 4 weeks for the base case. Consequently, all visits were essentially CCO application visits, and costs were calculated as such.

CCO, clostridial collagenase ointment; non-CCO, selective debridement alone.

Figure 2. Population metrics for individuals in different health states in clostridial collagenase ointment (CCO) added to selective debridement and selective debridement alone (non-CCO) over the 2-year period.

Figure 3. Epithelialized wound weeks with clostridial collagenase ointment (CCO) added to selective debridement and selective debridement alone (non-CCO) over the 2-year period.

Figure 4. Cumulative costs with clostridial collagenase ointment (CCO) added to selective debridement and selective debridement alone (non-CCO) over the 2-year period.

Figure 5. Influence of parameter uncertainty on the expected cost of clostridial collagenase ointment (CCO) added to selective debridement relative to selective debridement alone (non-CCO).

Figure 6. Influence of parameter uncertainty on the expected benefits of clostridial collagenase ointment (CCO) added to selective debridement relative to selective debridement alone (non-CCO).

Figure 7. Probabilistic sensitivity analysis. Each point on the plot corresponds to one trial in the Monte Carlo simulation comparing the incremental effectiveness and costs of therapy. The ellipse encompasses 95% confidence intervals.

Gold M, Siegel JE, Russell LB, et al., eds. Cost-effectiveness in health and medicine. New York, NY: Oxford University Press, 1996. Appendix A304–11

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Carter MJ, Gilligan AM, Waycaster CR, et al. Treating pressure ulcers with clostridial collagenase ointment: results from the US wound registry. Wound Repair Regen 2016; 24:904-12

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