Dissemination and Adoption of Comparative Effectiveness Research Findings When Findings Challenge Current Practices. Study Results

01/01/2013

The results of the trial for patients with spinal stenosis are presented in Table 4.1. The intention-to-treat analysis showed that surgery was more effective than nonsurgical treatment on the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) bodily pain scale and on patients’ self-reported ratings of symptom improvement but on few other primary or secondary outcomes. Patients with spinal stenosis had very high rates of crossover after randomized treatment assignment (as was the case for the two other subpopulations with disc herniation and degenerative spondylolisthesis). As shown in Table 4.1, only 67 percent of patients randomized to the surgical arm underwent surgery, while 43 percent of those randomized to nonsurgical treatment underwent surgery within two years of the baseline assessment. Patients who crossed over to receive surgery had high levels of self-rated disability, more psychological distress, worse symptoms, and, at baseline, a stronger preference for surgery.

Because such a large proportion of participants in the nonsurgical arm of the trial crossed over, the authors concluded that the relative superiority (or equivalence) of the treatments could not be determined from the intention-to-treat analysis. They therefore combined the data from the prospective-cohort study with data from the randomized cohort to create an observational cohort and analyzed the outcomes “as treated” (e.g., for patients who underwent surgery versus those who did not). The resulting observational-cohort study was not a randomized design, so the analysis adjusted for known baseline differences between patients in the two groups. This observational analysis found that surgery was superior to nonsurgical treatment across all primary and secondary outcomes. These effects held through two years of follow-up.

The clinical-trial protocol did not specify the type of procedure to be used for patients randomized to surgery, but in the vast majority of cases, decompression surgery rather than fusion surgery was the technique selected (89 percent versus 11 percent). Thus, this trial did not inform conclusions regarding the relative benefits of decompression surgery and fusion surgery (with or without instrumentation).

A cost-effectiveness analysis using patient-level data from SPORT found that surgery for spinal stenosis was moderately cost-effective at $77,600 for each quality-adjusted life year (QALY) gained, while surgery for spondylolisthesis was not cost effective ($115,600 per QALY gained).

Table 4.1

Results of the SPORT Trial

Outcome

Randomized Cohorta (intention-to-treat analysis,
N = 289)

Combined Randomized and Observational Cohortsa 
(as-treated analysis, N = 654)

Primary outcomes

 

 

SF-36 bodily pain scale

Surgery preferred

Surgery preferred

SF-36 physical function scale

No differenceb

Surgery preferred

Oswestry Disability Index (ODI)c

No difference

Surgery preferred

Secondary outcomes

 

 

Self-reported improvement

Surgery preferred

Surgery preferred

Satisfaction with current symptoms

No difference

Surgery preferred

Outcome

Randomized Cohorta (intention-to-treat analysis,
N = 289)

Combined Randomized and Observational Cohortsa 
(as-treated analysis, N = 654)

Satisfaction with care

No difference

Surgery preferred

Stenosis Bothersomeness Index

No difference

Surgery preferred

Leg Pain Bothersomeness Index

No difference

Surgery preferred

Low Back Pain Bothersomeness Index

No difference

Surgery preferred

Other

 

 

Underwent surgery

67% (surgical arm)d 

43% (nonsurgical arm)

 

Type of surgery

Decompression

Noninstrumented fusion

Instrumented fusion

 

89%

4%

7%

 

Intraoperative complication rate

8%

 

Postoperative complication rate

12%

 

aTwo-year outcomes are reported.

b“No difference” implies no statistically significant difference between surgical and nonsurgical groups.

cAmerican Academy of Orthopedic Surgery’s MODEMS version of the ODI was used.

dIn the observational cohort, 96 percent of patients who initially chose surgery underwent surgery at two years; 22 percent who initially chose nonsurgical management had undergone surgery at two years.

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