Revisiting The Cost-Effectiveness Of Recombinant Bone Morphogenetic Protein-2 Versus Iliac Crest Bone Graft In Spinal Arthrodesis

Abstract

Cost-Effectiveness analysis (CEA) studies used to compare the cost-effectiveness of two different surgical approaches, recombinant human bone morphogenetic protein-2 (rhBMP-2) and iliac crest bone graft (ICBG), have typically used up to two years of follow-up data, thus excluding any additional costs and interventions accumulated after that time period. To address this limitation, a future CEA is planned to compare the value of rhBMP-2 versus ICBG in lumbar fusion using five years follow-up from administrative data. This thesis had 2 objectives. The first objective was to perform a literature review that identified studies that provide or supplement the data necessary to conduct the future CEA. The second objective was to use the results from the literature review to perform a preliminary investigation of the planned CEA model. A systematic literature search of published literature through May 2015 was conducted using PubMed/MEDLINE, the Cochrane Collection Library, and the Tuft’s CEA Registry. Using a Markov model, a preliminary CEA compared rhBMP-2 to ICBG with regard to incremental cost-effectiveness ratios (ICERs) from both a payer and societal perspective. Transition probabilities derived from second surgery rates were extracted from two studies: one with differing rates between treatment groups, and one with similar rates between groups. Four subanalyses were performed in order to combine each set of second surgery rates with each cost perspective. Two threshold sensitivity analyses were conducted in order to test the effects of second surgery rates and indirect costs on the results of the analysis. Forty publications were identified that could contribute to the future study, and data was extracted from 11 of those 40 articles to perform the preliminary CEA. Knowledge gaps included lack of long-term follow-up of fusion rates and second surgery rates, and lack of quality reporting of utility and work status. Furthermore, there was disagreement between prospective and retrospective studies in fusion rates and second surgery rates. In the two subanalyses performed from the payer perspective, ICBG was more cost-effective than rhBMP-2, and the ICER values were $251,026/QALY and $849,893/QALY. In the two subanalyses performed from the societal perspective, rhBMP-2 was both less costly and more effective than ICBG, and the ICER was not needed to compare the interventions. From the payer perspective, rhBMP-2 became more cost-effective than ICBG when the difference in second surgery rates was greater than 13% after five years, and from the societal perspective, ICBG became more cost-effective than rhBMP-2 when the difference in indirect costs was less than $4,000 after five years. In conclusion, this thesis identified knowledge gaps in the literature and selected 40 publications that would be useful to a future CEA comparing the cost-effectiveness of rhBMP-2 and ICBG. The preliminary CEA showed that rhBMP-2 was less cost-effective than ICBG from a payer perspective, but more cost-effective from a societal perspective.