Table 4. Treatment Effect of Surgery By Secondary Outcome Measures of Spinal Stenosis and Degenerative Spondylolisthesis Patients According to Body Mass Index*.
| Outcome | Obesity (2 groups) | 1 Year | 2 Years | 3 Years | 4 Years |
|---|---|---|---|---|---|
|
| |||||
| SPS (RCT & OBS) | Treatment Effect (95% CI) | Treatment Effect (95% CI) | Treatment Effect (95% CI) | Treatment Effect (95% CI) | |
|
| |||||
| Stenosis Bothersomeness Index (0-24) (SE)§§ | Normal or overweight (BMI < 30) | -4.4 (-5.6,-3.2) | -3 (-4.3,-1.8) | -3.5 (-4.9,-2.2) | -3.5 (-5,-2) |
| Obese (BMI ≥ 30) | -5.3 (-6.8,-3.7) | -5.3 (-6.9,-3.7) | -3.3 (-5,-1.6) | -4 (-5.8,-2.2) | |
|
| |||||
| pvalue | 0.36 | 0.021 | 0.83 | 0.67 | |
|
| |||||
| Low Back Pain Bothersomeness (0-6) (SE)¶¶ | Normal or overweight | -1.3 (-1.7,-0.9) | -1.3 (-1.7,-0.9) | -1.3 (-1.7,-0.9) | -1 (-1.5,-0.5) |
| Obese | -1.8 (-2.3,-1.3) | -1.6 (-2.1,-1.1) | -1.3 (-1.9,-0.7) | -1.4 (-2,-0.8) | |
|
| |||||
| pvalue | 0.15 | 0.33 | 0.98 | 0.26 | |
|
| |||||
| Very/somewhat satisfied with symptoms (%) | Normal or overweight | 34.5 (24.3,44.8) | 36.7 (26.1,47.4) | 29.8 (18.2,41.5) | 33.6 (21,46.1) |
| Obese | 50.7 (39.5,61.9) | 51 (39.3,62.7) | 33 (19,47) | 31.2 (16.4,46) | |
|
| |||||
| pvalue | 0.044 | 0.08 | 0.73 | 0.85 | |
|
| |||||
| Self-rated progress: major improvement (%) | Normal or overweight | 37.9 (28,47.7) | 29.3 (18.6,40) | 28.6 (17.2,39.9) | 26.7 (14.3,39) |
| Obese | 53.3 (42.5,64) | 49 (37.5,60.5) | 42 (29.7,54.4) | 36.2 (23.9,48.5) | |
|
| |||||
| pvalue | 0.042 | 0.02 | 0.11 | 0.15 | |
|
| |||||
| Mental Component Summary (MCS)(0-100) (SE) †† | Normal or overweight | 1.5 (-0.4,3.4) | 1.4 (-0.6,3.3) | 0.9 (-1.2,3) | 1.9 (-0.5,4.2) |
| Obese | 0.6 (-1.8,2.9) | 3.9 (1.5,6.4) | 3.4 (0.8,6) | 3.1 (0.3,5.9) | |
|
| |||||
| pvalue | 0.53 | 0.099 | 0.13 | 0.49 | |
|
| |||||
| DS (RCT & OBS) | |||||
|
| |||||
| Stenosis Bothersomeness Index (0-24) (SE)§§ | Normal or overweight (BMI < 30) | -5.2 (-6.4,-4) | -5.1 (-6.3,-3.8) | -4.7 (-6,-3.3) | -5.1 (-6.5,-3.6) |
| Obese (BMI ≥ 30) | -6.6 (-8.1,-5) | -5.6 (-7.2,-3.9) | -5.5 (-7.3,-3.6) | -6.6 (-8.5,-4.8) | |
|
| |||||
| pvalue | 0.16 | 0.63 | 0.48 | 0.18 | |
|
| |||||
| Low Back Pain Bothersomeness (0-6) (SE)¶¶ | Normal or overweight | -1.2 (-1.6,-0.8) | -0.8 (-1.2,-0.4) | -0.7 (-1.1,-0.3) | -0.9 (-1.4,-0.4) |
| Obese | -1.5 (-2,-1) | -1.2 (-1.7,-0.7) | -0.8 (-1.4,-0.2) | -1.3 (-1.9,-0.7) | |
|
| |||||
| pvalue | 0.35 | 0.28 | 0.69 | 0.31 | |
|
| |||||
| Very/somewhat satisfied with symptoms (%) | Normal or overweight | 42.7 (33.3,52.2) | 39.4 (29.3,49.5) | 26.5 (15.1,37.9) | 30.3 (18.3,42.4) |
| Obese | 50.8 (39.5,62.1) | 31.5 (17.3,45.7) | 36.1 (21.2,50.9) | 43 (28.5,57.5) | |
|
| |||||
| pvalue | 0.26 | 0.38 | 0.34 | 0.24 | |
|
| |||||
| Self-rated progress: major improvement (%) | Normal or overweight | 44.4 (35,53.8) | 47.9 (38.3,57.6) | 48.4 (38.3,58.4) | 43.7 (32.6,54.7) |
| Obese | 59.4 (48.4,70.3) | 52.4 (40.2,64.6) | 40.3 (25.6,54.9) | 49.7 (35.6,63.8) | |
|
| |||||
| pvalue | 0.071 | 0.58 | 0.46 | 0.56 | |
|
| |||||
| Mental Component Summary (MCS)(0-100) (SE) †† | Normal or overweight | 0.3 (-1.5,2.2) | 1.2 (-0.7,3.2) | 1.8 (-0.2,3.9) | 2.7 (0.5,5) |
| Obese | 3.5 (1.1,5.9) | 2.5 (0,5.1) | 3.7 (0.9,6.5) | 1.6 (-1.4,4.6) | |
|
| |||||
| pvalue | 0.038 | 0.41 | 0.29 | 0.56 | |
Adjusted for age, gender, race, smoking status, compensation, joint, stomach, bowel, osteoporosis, number of moderate/severe stenotic levels, self-assessed health trend at baseline, treatment preference, baseline stenosis bothersomeness, other ** comorbiditiy, baseline score and center.
Treatment effect is the difference between the surgical and non-operative mean change from baseline. Analysis is done using a mixed model with a random subject intercept term. Treatment is a time-varying covariate where a patients' experience prior to surgery is attributed to the non-operative arm and time is measured from enrollment and his/her post-surgery outcomes are attributed to the surgical arm and time is measured from time of surgery.
The Sciatica Bothersomeness index ranges from 0 to 24, with lower scores indicating less severe symptoms.
The Low Back Pain Bothersomeness Scale ranges from 0 to 6, with lower scores indicating less severe symptoms
The SF-36 scores range from 0 to 100, with higher score indicating less severe symptoms.
Other comorbidities include: stroke, cancer, fibromyalgia, chronic fatigue syndrome, post traumatic stress disorder, alcohol, drug dependency, lung, liver, kidney, blood vessel, nervous system, migraine, anxiety.