Cost effectiveness study: CTDR QALYs are lower than accepted thresholds

Cervical total disc replacement proved to be a sustainable intervention for 2-level cervical spondylosis, according to results of a recently published study that analyzed data from a randomized control trial comparing 2-level cervical total disc replacement with the more traditional treatment: anterior cervical discectomy and fusion.

The goal of the data analysis was to measure the cost effectiveness and quality of both treatments, according to researchers.

Kee D. Kim, MD, and colleagues analyzed data from a previous randomized controlled trial with 2 years of follow-up. Its results suggested the two treatments had similar health outcomes for the indication in question – cervical spondylosis.

The original randomized controlled trial followed 330 patients for a 24 month period. To be included in that study, patients needed to be diagnosed with radiculopathy or myeloradiculopathy at two contiguous levels from C3 to C7 but not respond to a minimum of 6 weeks of conservative treatment.

Kim and colleagues used incremental cost-effectiveness of cervical total disc replacement (CTDR) vs. anterior cervical discectomy and fusion as the main outcome of their analysis.

“This is the first study that shows that for 2-level degenerative disease involving cervical spine, artificial disc is more cost-effective than traditional anterior cervical discectomy and fusion. However, I do want to caution that to be on this study the patients had to meet strict inclusion and exclusion criteria and our paper was based on just 2 year follow-up data,” Kim told Spine Surgery Today.

Kee D. Kim

In the study by Kim and colleagues, health states were constructed based on stratification of the Neck Disability Index and a VAS. In addition, the investigators used the SF-12 health survey questions answered in the study to convert those data into utilities values using an SF-6D mapping algorithm.

The costs of the procedures and any complications the patients may have developed were also calculated into the final analysis. Costs were calculated according to DRG codes from institutional billing data, which were applied to Medicare reimbursement rates for 2012.

Kim and colleagues also analyzed return-to-work data and, to determine the quality-adjusted life-years (QALYs) associated with both treatments, they developed a Markov model.

The study findings showed that at 24 months after treatment cervical total disc replacement (CTDR) patients had an average of 1.58 QALYs and anterior cervical discectomy patients had an average of 1.5 QALYs.

Kim and colleagues noted the incremental cost-effectiveness ratio of CTDR vs. ACDF was $24,594 per QALY at the 2-year follow up, which is below the threshold of $50,000 per QALY calculated for similar scenarios. However, they found CTDR was generally associated with $2,139 greater average cost.

“As such. this may not be generalizable to everyone with this type of problem and we are currently doing longer follow-up analysis,” Kim said. “Overall, I have been impressed by how well my patients are doing after two-level total disc arthroplasty with this particular artificial disc (Mobi-C Cervical Artificial Disc; LDR Spine),” he said. – by Robert Linnehan

Reference:

Ament KD. JAMA Surg. 2014;doi:10.1001/jamasurg.2014.716.

For more information:

Kee D. Kim, MD, can be reached at UC Davis Health System, 3301 C St.1500, Sacramento, CA 95816; email: kee.kim@ucdmc.ucdavis.edu.

Disclosure: Kim receives royalties from LDR Spine. LDR paid for the software used in the analysis.