Table 5.
Change Scores and Treatment Effects for Primary and Secondary Outcomes in the Randomized and Observational IDH Cohorts Combined, According to BMI and Treatment Received*
| IDH | 1-Year | 2-Year | 3-Year | 4-Year | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Outcome | BMI | Surgical | Non- operative |
Treatment Effect† (95% CI) |
Surgical | Non- operative |
Treatment Effect† (95% CI) |
Surgical | Non- operative |
Treatment Effect† (95% CI) |
Surgical | Non- operative |
Treatment Effect† (95% CI) |
| SF-36 Bodily Pain (BP) (0–100) (SE)†† |
BMI < 30 | 47.5 (1.1) | 34.1 (1.4) | 13.4 (10, 16.7) | 48 (1.1) | 34.9 (1.4) | 13.1 (9.7, 16.4) | 48.7 (1.1) | 35.8 (1.4) | 12.9 (9.4, 16.4) | 50 (1.2) | 33.4 (1.5) | 16.6 (12.9, 20.3) |
| 30 ≤ BMI < 35 | 43 (2) | 26.4 (2.9) | 16.6 (10.1, 23.1) | 41.6 (2) | 35.1 (3) | 6.6 (−0.3, 13.4) | 41.7 (2.1) | 30.8 (3.2) | 11 (3.7, 18.2) | 45 (2.2) | 34.2 (3.3) | 10.8 (3.3, 18.3) | |
| BMI ≥ 35 | 47.3 (2.5) | 28.9 (3.8) | 18.3 (9.9, 26.8) | 40.7 (2.5) | 24.9 (4) | 15.8 (7.1, 24.5) | 41.6 (2.7) | 20.9 (4.2) | 20.7 (11.4, 30) | 42.8 (2.7) | 25.6 (4.3) | 17.2 (7.8, 26.7) | |
| pvalue | 0.13 | 0.031 | 0.43 | 0.002 | 0.051 | 0.16 | 0.002 | 0.002 | 0.23 | 0.013 | 0.19 | 0.37 | |
| SF-36 Physical Function (PF) (0–100) (SE)†† |
BMI < 30 | 46.2 (1) | 31.3 (1.2) | 14.8 (11.8, 17.9) | 45.7 (1) | 32.3 (1.3) | 13.4 (10.4, 16.5) | 46.4 (1) | 33.5 (1.3) | 12.9 (9.7, 16.1) | 47.7 (1.1) | 32 (1.4) | 15.7 (12.4, 19) |
| 30 ≤ BMI < 35 | 39.1 (1.8) | 23.3 (2.6) | 15.8 (10, 21.7) | 37.5 (1.8) | 29.5 (2.8) | 8 (1.8, 14.1) | 36.9 (2) | 26.1 (2.9) | 10.8 (4.2, 17.3) | 36.5 (2.1) | 26.2 (3) | 10.3 (3.5, 17.1) | |
| BMI ≥ 35 | 40.7 (2.3) | 17.1 (3.5) | 23.6 (16, 31.3) | 38.6 (2.3) | 17.9 (3.6) | 20.7 (12.9, 28.5) | 40.7 (2.4) | 15.7 (3.8) | 25 (16.7, 33.3) | 37.9 (2.4) | 18.5 (3.9) | 19.4 (10.9, 27.9) | |
| pvalue | <0.001 | <0.001 | 0.10 | <0.001 | <0.001 | 0.04 | <0.001 | <0.001 | 0.016 | <0.001 | 0.002 | 0.21 | |
| Mental Component Summary (MCS) (0–100) (SE)†† |
BMI < 30 | 7.7 (0.4) | 4.4 (0.6) | 3.3 (1.9, 4.7) | 6.8 (0.4) | 4.2 (0.6) | 2.6 (1.2, 3.9) | 7 (0.4) | 4 (0.6) | 2.9 (1.5, 4.4) | 6.5 (0.5) | 4.6 (0.6) | 2 (0.5, 3.5) |
| 30 ≤ BMI < 35 | 8 (0.8) | 5.6 (1.2) | 2.3 (−0.3, 5) | 5.8 (0.8) | 5.3 (1.2) | 0.5 (−2.3, 3.3) | 5.4 (0.9) | 4.7 (1.3) | 0.7 (−2.3, 3.6) | 5.2 (0.9) | 4 (1.3) | 1.1 (−1.9, 4.2) | |
| BMI ≥ 35 | 7.7 (1) | 1.6 (1.6) | 6.1 (2.7, 9.6) | 5.5 (1) | 5.5 (1.6) | 0 (−3.6, 3.5) | 4.7 (1.1) | 3.7 (1.7) | 1 (−2.8, 4.7) | 4.5 (1.1) | 2.2 (1.8) | 2.3 (−1.6, 6.2) | |
| pvalue | 0.95 | 0.11 | 0.21 | 0.37 | 0.57 | 0.21 | 0.064 | 0.87 | 0.28 | 0.13 | 0.44 | 0.86 | |
| Oswestry Disability Index (ODI) (0–100) (SE))‡‡ |
BMI < 30 | −38.5 (0.8) | −25.2 (1) | −13.3 (−15.8, −10.8) | −39.2 (0.8) | −25.6 (1) | −13.6 (−16.1, −11.1) | −39.7 (0.8) | −27 (1.1) | −12.7 (−15.3, −10.1) | −40.1 (0.9) | −26.1 (1.1) | −14 (−16.7, −11.3) |
| 30 ≤ BMI < 35 | −34.7 (1.5) | −18.1 (2.1) | −16.6 (−21.3, −11.9) | −32.5 (1.5) | −24.2 (2.3) | −8.3 (−13.4, −3.3) | −31.2 (1.6) | −21.1 (2.4) | −10.1 (−15.4, −4.8) | −33.3 (1.7) | −23.3 (2.5) | −10 (−15.5, −4.5) | |
| BMI ≥ 35 | −35.9 (1.9) | −14.5 (2.8) | −21.5 (−27.6, −15.3) | −32.2 (1.9) | −19.3 (2.9) | −12.9 (−19.2, −6.6) | −34.4 (2) | −15.3 (3.2) | −19.1 (−26, −12.3) | −34.1 (2) | −18.3 (3.2) | −15.8 (−22.7, −9) | |
| pvalue | 0.064 | <0.001 | 0.035 | <0.001 | 0.12 | 0.17 | <0.001 | <0.001 | 0.11 | <0.001 | 0.049 | 0.33 | |
| Sciatica Bothersomeness Index (0–24) (SE)§§ |
BMI < 30 | −11.3 (0.3) | −8.3 (0.3) | −3.1 (−3.9, −2.2) | −11.3 (0.3) | −8.2 (0.3) | −3.1 (−3.9, −2.2) | −11.5 (0.3) | −8.6 (0.3) | −2.9 (−3.7, −2) | −12.1 (0.3) | −8.3 (0.4) | −3.8 (−4.7, −2.9) |
| 30 ≤ BMI < 35 | −10.8 (0.5) | −6.8 (0.7) | −4 (−5.5, −2.5) | −10 (0.5) | −7.7 (0.7) | −2.3 (−4, −0.7) | −10 (0.5) | −6.8 (0.8) | −3.2 (−4.9, −1.5) | −10 (0.5) | −8.6 (0.8) | −1.5 (−3.3, 0.3) | |
| BMI ≥ 35 | −10.8 (0.6) | −6.5 (0.9) | −4.2 (−6.2, −2.2) | −9.8 (0.6) | −6.4 (0.9) | −3.4 (−5.5, −1.4) | −9.9 (0.6) | −6.8 (1) | −3.1 (−5.3, −0.9) | −10.2 (0.6) | −5.6 (1) | −4.6 (−6.8, −2.3) | |
| pvalue | 0.50 | 0.046 | 0.36 | 0.011 | 0.16 | 0.64 | 0.006 | 0.031 | 0.93 | <0.001 | 0.037 | 0.04 | |
| Low Back Pain Bothersomeness (0–6) (SE)¶¶ |
BMI < 30 | −2.2 (0.1) | −1.4 (0.1) | −0.7 (−1, −0.4) | −2.2 (0.1) | −1.4 (0.1) | −0.8 (−1.1, −0.5) | −2.3 (0.1) | −1.5 (0.1) | −0.8 (−1.1, −0.5) | −2.3 (0.1) | −1.4 (0.1) | −0.9 (−1.2, −0.6) |
| 30 ≤ BMI < 35 | −2 (0.1) | −1.2 (0.2) | −0.8 (−1.3, −0.3) | −1.8 (0.1) | −1.6 (0.2) | −0.2 (−0.7, 0.3) | −1.8 (0.2) | −1.2 (0.2) | −0.6 (−1.1, −0.1) | −1.9 (0.2) | −1.6 (0.2) | −0.2 (−0.8, 0.4) | |
| BMI ≥ 35 | −2.2 (0.2) | −0.7 (0.3) | −1.5 (−2.1, −0.9) | −1.9 (0.2) | −1.3 (0.3) | −0.5 (−1.1, 0.1) | −1.9 (0.2) | −1.2 (0.3) | −0.7 (−1.4, 0) | −1.9 (0.2) | −0.9 (0.3) | −1 (−1.7, −0.3) | |
| pvalue | 0.41 | 0.022 | 0.076 | 0.041 | 0.72 | 0.20 | 0.011 | 0.27 | 0.91 | 0.036 | 0.19 | 0.10 | |
| Very/somewhat satisfied with symptoms (%) |
BMI < 30 | 73.8 | 46.4 | 27.4 (19.7, 35.2) | 76.9 | 51.2 | 25.8 (18, 33.6) | 75.7 | 51.4 | 24.3 (16.2, 32.4) | 78.4 | 49 | 29.4 (21, 37.8) |
| 30 ≤ BMI < 35 | 71 | 39.3 | 31.7 (17.1, 46.3) | 68.8 | 46.1 | 22.7 (6.8, 38.5) | 65.9 | 48.9 | 16.9 (−0.3, 34.1) | 70.4 | 46.6 | 23.8 (6.3, 41.3) | |
| BMI ≥ 35 | 79 | 30.5 | 48.4 (30.6, 66.2) | 72.6 | 32.6 | 39.9 (20.9, 58.9) | 78 | 38.5 | 39.5 (19, 60.1) | 74.7 | 24.8 | 50 (31.3, 68.6) | |
| p-value | 0.44 | 0.19 | 0.14 | 0.16 | 0.14 | 0.39 | 0.10 | 0.44 | 0.21 | 0.23 | 0.082 | 0.17 | |
| Self-rated progress: major improvement (%) |
BMI < 30 | 83.8 | 57.6 | 26.2 (18.7, 33.6) | 80.1 | 62.1 | 18 (10.3, 25.6) | 77.3 | 56.7 | 20.6 (12.4, 28.8) | 80.4 | 53.8 | 26.6 (18.2, 35.1) |
| 30 ≤ BMI < 35 | 82.5 | 38.8 | 43.7 (29.8, 57.6) | 76.2 | 54.4 | 21.8 (6.1, 37.5) | 69.8 | 50.5 | 19.3 (2.2, 36.5) | 72.8 | 45.1 | 27.7 (10.4, 45.1) | |
| BMI ≥ 35 | 80.6 | 59.1 | 21.5 (2.1, 40.9) | 70.6 | 40.1 | 30.5 (10.2, 50.8) | 76.9 | 43.5 | 33.4 (11.9, 54.9) | 77.3 | 46.4 | 31 (8.6, 53.3) | |
| p-value | 0.76 | 0.044 | 0.19 | 0.15 | 0.045 | 0.70 | 0.27 | 0.36 | 0.51 | 0.24 | 0.53 | 0.95 | |
| Work status: working (%) |
BMI < 30 | 85.9 | 84.1 | 1.8 (−4.3, 7.8) | 86 | 84.1 | 1.9 (−4.3, 8.1) | 86.6 | 80.4 | 6.3 (−0.7, 13.2) | 86.9 | 78.4 | 8.5 (0.8, 16.2) |
| 30 ≤ BMI < 35 | 85.9 | 83.7 | 2.2 (−9, 13.5) | 84.5 | 87.5 | −3 (−13.8, 7.8) | 75.2 | 79.2 | −3.9 (−19.6, 11.8) | 75.3 | 82.1 | −6.8 (−22.5, 8.9) | |
| BMI ≥ 35 | 87.7 | 85.4 | 2.3 (−11, 15.5) | 84.2 | 87.1 | −2.8 (−16.1, 10.5) | 79.5 | 75.1 | 4.3 (−15.9, 24.5) | 79.8 | 65.5 | 14.3 (−9.3, 37.8) | |
| p-value | 0.89 | 0.96 | 0.99 | 0.89 | 0.77 | 0.67 | 0.042 | 0.82 | 0.52 | 0.038 | 0.41 | 0.22 | |
Adjusted for age, gender, marital status, smoking status, race, compensation, herniation location, working status, stomach comorbidity, depression, other comorbidity, self-rated health trend, duration of most recent episode, treatment preference and baseline score (for SF-36, ODI, and Sciatica Bothersomeness), and center. Other comorbidities include: stroke, diabetes, osteoporosis, cancer, fibromyalgia, chronic fatigue syndrome (CFS), post traumatic stress disorder (PTSD), alcohol, drug dependency, heart, lung, liver, kidney, blood vessel, nervous system, hypertension, migraine, anxiety, stomach, bowel.
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.
The Sciatica Bothersomeness index range from 0 to 24, with lower scores indicating less severe symptoms.
The Low Back Pain Bothersomness Scale ranges from 0 to 6, with lower scores indicating less severe symptoms