Table 3. Treatment Effect of Surgery By Primary 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) | |
|
| |||||
| SF-36 Bodily Pain (BP) (0-100) (SE)†† | Normal or overweight (BMI < 30) | 14.6 (10.1,19.1) | 13.4 (8.7,18.1) | 12.9 (7.9,17.8) | 12.6 (7.2,18.1) |
| Obese (BMI ≥ 30) | 17.2 (11.6,22.8) | 16.3 (10.5,22.1) | 16.7 (10.6,22.9) | 15.9 (9.4,22.4) | |
|
| |||||
| pvalue | 0.47 | 0.44 | 0.32 | 0.44 | |
|
| |||||
| SF-36 Physical Function(PF) (0-100) (SE)†† | Normal or overweight | 13.5 (9.3,17.6) | 9.8 (5.5,14.2) | 9.5 (4.9,14.1) | 7.4 (2.3,12.4) |
| Obese | 16.3 (11,21.6) | 10.6 (5.1,16) | 13.6 (7.8,19.4) | 12.8 (6.7,18.9) | |
|
| |||||
| pvalue | 0.40 | 0.84 | 0.26 | 0.17 | |
|
| |||||
| Oswestry Disability Index (ODI) (0-100) (SE)‡‡ | Normal or overweight | -10.1 (-13.4,-6.8) | -9.3 (-12.8,-5.9) | -7.8 (-11.5,-4.1) | -7.4 (-11.4,-3.3) |
| Obese | -15.7 (-19.9,-11.5) | -14.2 (-18.5,-9.9) | -13.1 (-17.7,-8.5) | -13.9 (-18.8,-9) | |
|
| |||||
| pvalue | 0.036 | 0.076 | 0.07 | 0.037 | |
|
| |||||
| DS (RCT & OBS) | |||||
|
| |||||
| SF-36 Bodily Pain (BP) (0-100) (SE)†† | Normal or overweight (BMI < 30) | 16.7 (12.4,21) | 17.6 (13,22.1) | 15.6 (10.8,20.4) | 13.8 (8.7,19) |
| Obese (BMI ≥ 30) | 20.7 (15,26.4) | 20 (14,26.1) | 19.6 (13,26.1) | 17.2 (10.4,24) | |
|
| |||||
| pvalue | 0.26 | 0.51 | 0.32 | 0.43 | |
|
| |||||
| SF-36 Physical Function(PF) (0-100) (SE)†† | Normal or overweight | 16 (11.9,20.1) | 15.9 (11.6,20.2) | 14.4 (9.9,19) | 14 (9,18.9) |
| Obese | 20.7 (15.3,26.1) | 17.9 (12.2,23.6) | 19.9 (13.6,26.1) | 25.6 (19.1,32.1) | |
|
| |||||
| pvalue | 0.17 | 0.58 | 0.16 | 0.004 | |
|
| |||||
| Oswestry Disability Index (ODI) (0-100) (SE)‡‡ | Normal or overweight | -15.4 (-18.5,-12.2) | -14.5 (-17.8,-11.1) | -11.7 (-15.3,-8.2) | -12.6 (-16.4,-8.8) |
| Obese | -19.6 (-23.8,-15.4) | -18.4 (-22.8,-14) | -14.4 (-19.2,-9.6) | -17.5 (-22.5,-12.5) | |
|
| |||||
| pvalue | 0.11 | 0.15 | 0.37 | 0.12 | |
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 SF-36 scores range from 0 to 100, with higher score indicating less severe symptoms.
The Oswestry Disability Index ranges from 0 to 100, with lower scores 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.