Clinical effectiveness and cost-effectiveness of bone morphogenetic proteins in the non-healing of fractures and spinal fusion: a systematic review

Abstract

Objectives: To assess the clinical effectiveness and cost-effectiveness of bone morphogenetic protein (BMP) for the treatment of spinal fusions and the healing of fractures compared with the current standards of care.

Data sources: Electronic databases, related journals and references from identified studies were searched in January 2006, with an updated search only for randomised controlled trials (RCTs) in November 2006.

Review methods: A systematic review of available data was conducted. The data from selected studies were then analysed and graded according to quality and processed to give a value to the efficacy of BMP. Existing models were modified or updated to evaluate the cost-effectiveness of BMP for open tibial fractures and spinal fusion.

Results: All selected trials were found to have several methodological weaknesses. Insufficient sample size in most trials, meant that patient baseline comparability between trial arms was not achieved and the statistical power to detect a moderate effect was low. Data did indicate that BMP increased fracture union among patients with acute tibial fractures and found that high-dose BMP is more effective than a lower dose for open tibial fractures. The healing rate in the BMP group was not found to be statistically significantly different from that in the autogenous bone grafting group for patients with tibial non-union fractures, but BMP reduced the number of secondary interventions in patients with acute tibial fractures compared with controls. There was very limited evidence that BMP in scaphoid non-union was safe and may help to accelerate non-union healing when used in conjunction with either autograft or allograft. There was evidence that BMP-2 is more effective than autogenous bone graft for radiographic fusion in patients with single-level degenerative disc disease. No significant difference was found when BMP-7 was compared with autograft for degenerative spondylolisthesis with spinal stenosis and spondylolysis. The use of BMP was associated with a reduced operating time, improvement in clinical outcomes and a shorter hospital stay as compared with autograft. The proportion of secondary interventions tended to be lower in the BMP group than the control, but not of statistical significance. Trial data on time to return to work postoperatively were sometimes difficult to interpret because of unclear or inappropriate data analysis methods. The incremental cost of BMP for open tibial fractures was estimated to be about 3.5 million pounds per year in the UK. The estimated incremental cost per quality-adjusted life-year (QALY) gained is 32,603 pounds. The probability that cost per QALY gained is less than 30,000 pounds for open tibial fracture is 35.5%. The cost-effectiveness ratio is sensitive to the price of BMP and the severity of open tibial fractures. The use of recombinant human bone morphogenetic protein for spinal fusion surgery may increase the cost to the UK NHS by about 1.3 million pounds per year. The estimated incremental cost per QALY gained was about 120,390 pounds. The probability that BMP is cost-effective (i.e. cost/QALY less than 30,000 pounds) was only 6.4%. From the societal perspective, the estimated total cost of using BMP for spinal fusion is about 4.2 million pounds per year in the UK.

Conclusions: Additional BMP treatment plus conventional intervention is more effective than conventional intervention alone for union of acute open tibial fractures. The cost-effectiveness of additional BMP may be improved if the price of BMP is reduced or if BMP is mainly used in severe cases. BMP may eliminate the need for autogenous bone grafting so that costs and complications related to harvesting autograft can be avoided. In non-unions, there is no evidence that BMP is more or less effective than bone graft; however, it is currently used when bone graft and other treatments have failed. The use of BMP-2 in spinal fusion surgery seems to be more effective than autogenous bone graft in terms of radiographic spinal fusion among patients with single-level degenerative disc disease. There is a lack of evidence about the effectiveness of BMP for other spinal disorders including spondylolisthesis and spinal stenosis. There was limited evidence showing that BMP is associated with greater improvement in clinical outcomes. According to the results of economic evaluation, the use of BMP for spinal fusion is unlikely to be cost-effective. The following areas would benefit from further research: clinical trials of BMP that include formal economic evaluation, a multicentre RCT of fracture non-union and of interbody and/or posterolateral spinal fusion, trials of non-tibial acute long bone fractures, and RCTs comparing BMP-2, BMP-7 and controls.