An early cost analysis of magnetic bone growth stimulation in England

Figures & data

Table 1. Clinical estimations

Parameter	Value	Source
Percentage that heal within 6–9 months of treatment post injury^a	72.1%^a	Phillips, M. et al. 2016.^5
Weighted time to healing^a	6.83 months^a	Phillips, M. et al. 2016. ^5
Transition success probability^a	16.82%^a	Calculated from data in Phillips, M. et al. 2016. ^5
Surgery success probability	86.0%	Gebauer et al. 2005.^6
Infection risk	1.4%	Exogen report^1
Monthly probability of unhealed fracture healing without intervention	0.2%	Assumption based on clinical input
Monthly probability of having surgery for an unhealed fracture	50.0%	Assumption based on clinical input

^aUsed solely in the CMF OL1000 arm of the model.

Table 2. Cost inputs

Parameter	Value	Source
Cost of CMF OL1000 (one-off cost per person)	£2,500	Price charged by DJO Global
Unhealed: Not infected (monthly cost)	£220	National schedule of reference costs 2019^8, NICE EAC review report^a 2019^9, PSSRU 2019^10, Portsmouth CCG spending^a 2013^11, Exogen report^1.
Surgery (one-off cost)	£4,175	NICE EAC review report^a 2019^6, HES 2019^9, NICE CG124^a10, National schedule of reference costs 2019^5, NICE EAC review report^a 2019^9, PSSRU 2019^10, Exogen report^1
Unhealed: infected (one-off cost)	£15,203	National schedule of reference costs 2019^5, NICE EAC review report^a 2019^9, PSSRU 2019^10, Exogen report^1 (resource use).
Healed (monthly cost in first month only)	£29	Portsmouth CCG spending^a 2013^11.

^aInflated using PSSRU to 2018/19 prices

NICE EAC – National Institute for Health and Care Excellence, external assessment center. PSSRU – Personal Social Services Research Unit. HES – Hospital Episode Statistics. NICE CG – National Institute for Health and Care Excellence, clinical guidelines.

Figure 1. Markov model of all health states associated with tibial fracture nonunion.

This figure shows the model structure whereby patients either enter the Markov model using CMF OL1000 or standard care (surgery). The Markov model structure is similar in both treatment arms. Numbers on arrows represent the transition probabilities. Patients using CMF OL1000 enter the model in the ‘unhealed: not infected (1)’ health state, whilst patients using standard care enter directly in the ‘surgery’ health state. After 9 cycles in ‘unhealed: not infected (1)’ patients who do not experience healing must transition to surgery. Infection refers to deep bone infection.* Note that this transition occurs after a delay of 6 months for healing (not pictured for simplicity).

Table 3. Cost per patient breakdown and clinical outcomes

Outcomes	CMF OL1000	Surgical Care	Difference Between Groups (Surgical Care as Reference)	Percentage Change Between Groups
Cost outcomes (per patient)
Unhealed: Not infected	£3,561	£71	£3,490	+4933.0%
Surgery	£1,002	£5,395	-£4,393	−81.4%
Unhealed: infected	£46	£246	-£201	−81.3%
Healed	£28	£28	£0	0%
Total	£4,637	£5,741	-£1,104	−19%
Clinical outcomes (per patient)
Total surgical procedures	0.22	1.16	−0.95	−81.0%
Total number of deep infections	0.00	0.02	−0.01	−99.9%
Average time to fracture healing (months) from entry to the model	6.43	8.49	−2.1	−24.0%

Figure 2. Tornado diagram presenting deterministic sensitivity analysis.

The tornado diagram presents the impact of varying each model input univariately on the results of the model.