2012년 10월 6일 토요일

Who Should Have Surgery for an Intervertebral Disc Herniation? Comparative Effectiveness Evidence From the Spine Patient Outcomes Research Trial

Surgery [Spine 2012 ; 37 : 140 – 149]

Title: Who Should Have Surgery for an Intervertebral Disc Herniation?
          Comparative Effectiveness Evidence From the Spine Patient Outcomes Research Trial

Adam Pearson
Jon Lurie
Tor Tosteson
Wenyan Zhao
William Abdu
Sohail Mirza
James Weinstein

Study Design.
Combined prospective randomized controlled trial and observational cohort study of intervertebral disc herniation (IDH), an as-treated analysis.

Objective.
To determine modifiers of the treatment effect (TE) of surgery (the difference between surgical and nonoperative outcomes) for IDH using subgroup analysis.

Summary of Background Data.
The Spine Patient Outcomes Research Trial demonstrated a positive surgical TE for IDH at the group level. However, individual characteristics may affect TE. No prior studies have evaluated TE modifiers in IDH.

Methods.
1. *Discectomy group: 788, *Nonoperative group: 404

2. Thirty-seven baseline variables to define subgroups for calculating the time-weighted average TE for the
    Oswestry Disability Index (ODI) across 4 years (TE =Δ ODI surgery - Δ ODI nonoperative) were used.

3. Variables with significant subgroup-by treatment interactions (P<0.1) were simultaneously entered into
    a multivariate model to select independent TE predictors.

Results.
1. Significant improvement in all subgroups with surgery than nonoperative treatment (p<0.05)

2. Minimally adjusted univariate analyses
à Greater treatment effect (TE): Marriage, absence of joint problems, worsening symptom trend at
      baseline, high school education or less, older age, no worker’s compensation, longer duration of
      symptoms, and an SF-36 mental component score (MCS) less than 35.

3. Multivariate analysis (Independent TE modifiers)
à being married (TE, 15.8 vs. 7.7 single, P<0.001)
à absence of joint problems (TE, 14.6 vs. 10.3 joint problems, P=0.012)
à worsening symptoms (TE, 15.9 vs. 11.8 stable symptoms, P=0.032)

4. TEs were greatest in married patients with worsening symptoms (18.3) vs. single patients with
    stable symptoms (7.8).

Conclusion.
Improvement more with surgery than with nonoperative treatment in strict inclusion criteria, regardless of specific characteristics
However, being married, without joint problems, and worsening symptom trend at baseline were associated with a greater TE.

"This comes from Spine (c) 2012 Lippincott Williams & Wilkins, Inc."