Surgery for degenerative cervical myelopathy is “cost-effective” and “should be supported”

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Value for money is an increasingly important part of hospital payer decision-making. In a The Spine Journal Outstanding Paper-winning study, a team from Toronto Western Hospital (Toronto, Canada) sought to investigate the lifetime cost-effectiveness of the surgical treatment of degenerative cervical myelopathy.

Evaluating the costly but often effective option, the team set about their research by recording Short Form-Six Dimension (SF-6D) health utility scores of patients undergoing degenerative cervical myelopathy surgery at a single centre enrolled in the North American or International AOSpine Cervical Spondylotic Myelopathy studies.

Measured at baseline, six, 12 and 24-months, the SF-6D scores were used to calculate quality of life-adjusted years (QALY). Costs were determined using the centre’s micro-cost database of operative costs and other treatment costs incurred from pre-surgery preparation to two-year follow-up. Given that the data came from 2005–2011 results, the researchers inflated costs according to January 2015 levels.

Using a Markov state transitional model, the team worked out lifetime cost-utility ratios. To compensate for the single-centre study design, the researchers used two models. “The first included a highly conservative assumption that individuals undergoing nonoperative management would not experience any neurological decline,” the authors explained. “This constraint was relaxed in the second model to permit more general parameters based on the established natural history.”

Of the 171 patients assessed, follow-up was achieved in 96.5% of patients. The researchers found that, on average, the mean QALY increase over the study period was 0.139 (p<0.001), with treatment costs averaging C$19,217.82±12,404.23, largely (65.7%) attributable to operative costs. Under the conservative model, the authors calculated a cost-effectiveness ratio of C$20,547.84 per QALY gained. The less conservative model demonstrated a lifetime cost-effectiveness of C$11,496.02 per QALY gained. According to the World Health Organisation’s “very cost-effective” definition (C$54,000 per QALY), 94.7% of conservative estimates and 97% of more general estimates fell within this criterion.

Whilst this study’s major strengths lie in its “large sample size, rigorous prospective collection of data and acquisition of detailed micro-cost data,” the authors report that it is limited by its single-arm design—which may not compensate for differing costs at other institutions, for example—and its focus on costs from a hospital payer perspective.

Concluding that, in spite of these limits, this research demonstrates that “the incremental cost-utility estimates are well within the generally accepted willingness-to-pay thresholds,” the authors assert that their results “may serve to guide policy decisions” for an effective treatment.