SPS – Change Scores and Treatment Effects for Primary and Secondary Outcomes in the Randomized and Observational SPS Cohorts Combined, According to BMI and Treatment Received*
| SPS | 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 | 29.6 (1.6) | 15 (1.9) | 14.6 (10.1, 19.1) | 30 (1.6) | 16.6 (2) | 13.4 (8.7, 18.1) | 29.9 (1.6) | 17 (2.1) | 12.9 (8, 17.8) | 29.2 (1.8) | 16.6 (2.3) | 12.6 (7.1, 18) |
| 30 ≤ BMI < 35 | 31 (2.4) | 13.9 (2.9) | 17.1 (10.1, 24.2) | 28.1 (2.5) | 10 (3.1) | 18.1 (10.6, 25.5) | 26.6 (2.5) | 11.2 (3.2) | 15.4 (7.7, 23.1) | 25.8 (2.7) | 7.4 (3.4) | 18.4 (10.3, 26.6) | |
| BMI ≥ 35 | 30.1 (3.5) | 12.6 (3.8) | 17.5 (8.3, 26.8) | 23.6 (3.3) | 10.2 (3.9) | 13.4 (4.2, 22.6) | 26.9 (3.3) | 7.4 (4.4) | 19.5 (9.4, 29.6) | 21 (3.5) | 9.4 (4.4) | 11.6 (1.1, 22.1) | |
| pvalue | 0.88 | 0.84 | 0.76 | 0.19 | 0.11 | 0.55 | 0.45 | 0.081 | 0.49 | 0.085 | 0.054 | 0.44 | |
| SF-36 Physical Function (PF) (0–100) (SE)†† |
BMI < 30 | 27.1 (1.5) | 13.6 (1.8) | 13.5 (9.3, 17.7) | 24.9 (1.5) | 15.1 (1.9) | 9.8 (5.4, 14.2) | 23.3 (1.6) | 13.8 (2) | 9.5 (4.9, 14.1) | 22.5 (1.7) | 15.1 (2.2) | 7.4 (2.3, 12.5) |
| 30 ≤ BMI < 35 | 24.2 (2.4) | 5.1 (2.8) | 19.1 (12.5, 25.7) | 20.6 (2.4) | 7.2 (2.9) | 13.4 (6.5, 20.4) | 17.8 (2.5) | 4.4 (3.1) | 13.4 (6.1, 20.6) | 18.4 (2.6) | 3.2 (3.2) | 15.2 (7.6, 22.9) | |
| BMI ≥ 35 | 22.2 (3.3) | 10.7 (3.6) | 11.5 (2.8, 20.2) | 15 (3.2) | 9.2 (3.7) | 5.9 (−2.7, 14.5) | 18 (3.2) | 3.7 (4.2) | 14.3 (4.8, 23.8) | 17.9 (3.4) | 9.2 (4.3) | 8.7 (−1.3, 18.6) | |
| pvalue | 0.32 | 0.037 | 0.27 | 0.012 | 0.053 | 0.39 | 0.089 | 0.011 | 0.52 | 0.26 | 0.009 | 0.23 | |
| Mental Component Summary (MCS) (0–100) (SE) †† |
BMI < 30 | 3.9 (0.7) | 2.3 (0.8) | 1.5 (−0.4, 3.4) | 3.1 (0.7) | 1.7 (0.8) | 1.4 (−0.6, 3.4) | 2.3 (0.7) | 1.5 (0.9) | 0.9 (−1.2, 3) | 2.9 (0.7) | 1 (1) | 1.9 (−0.4, 4.3) |
| 30 ≤ BMI < 35 | 3.4 (1) | 2.5 (1.2) | 0.9 (−2, 3.8) | 4.6 (1) | −0.9 (1.3) | 5.6 (2.5, 8.7) | 3.7 (1) | −1.2 (1.3) | 4.9 (1.6, 8.1) | 1.7 (1.1) | −1.5 (1.4) | 3.2 (−0.3, 6.6) | |
| BMI ≥ 35 | 2.9 (1.4) | 2.8 (1.5) | 0.2 (−3.7, 4.1) | 4.2 (1.3) | 2.8 (1.6) | 1.4 (−2.5, 5.3) | 2.4 (1.4) | 1.5 (1.8) | 0.9 (−3.4, 5.2) | 3.1 (1.5) | −0.2 (1.9) | 3.2 (−1.3, 7.7) | |
| pvalue | 0.80 | 0.97 | 0.81 | 0.38 | 0.13 | 0.064 | 0.53 | 0.22 | 0.10 | 0.62 | 0.36 | 0.77 | |
| Oswestry Disability Index (ODI) (0–100) (SE))‡‡ |
BMI < 30 | −20.8 (1.2) | −10.6 (1.4) | −10.1 (−13.4, −6.8) | −20.8 (1.2) | −11.4 (1.5) | −9.3 (−12.8, −5.8) | −19.1 (1.2) | −11.2 (1.6) | −7.8 (−11.5, −4.2) | −20.1 (1.3) | −12.7 (1.7) | −7.4 (−11.4, −3.3) |
| 30 ≤ BMI < 35 | −21.3 (1.9) | −5.1 (2.2) | −16.2 (−21.5, −11) | −20.6 (1.9) | −5.6 (2.3) | −15 (−20.5, −9.5) | −17.6 (1.9) | −5.4 (2.4) | −12.3 (−18.1, −6.5) | −17.6 (2) | −2.3 (2.6) | −15.3 (−21.4, −9.2) | |
| BMI ≥ 35 | −22.4 (2.6) | −7.7 (2.9) | −14.7 (−21.6, −7.8) | −18.2 (2.5) | −5.7 (2.9) | −12.5 (−19.2, −5.7) | −19.5 (2.5) | −5.4 (3.3) | −14.1 (−21.5, −6.6) | −17.3 (2.7) | −6.4 (3.4) | −10.9 (−18.9, −3) | |
| pvalue | 0.84 | 0.096 | 0.11 | 0.63 | 0.048 | 0.20 | 0.78 | 0.069 | 0.20 | 0.46 | 0.003 | 0.091 | |
| Stenosis Bothersomeness Index (0–24) (SE)§§ |
BMI < 30 | −8.2 (0.4) | −3.9 (0.5) | −4.4 (−5.6, −3.2) | −8.4 (0.4) | −5.4 (0.5) | −3 (−4.3, −1.7) | −8.2 (0.4) | −4.6 (0.6) | −3.5 (−4.9, −2.2) | −8.1 (0.5) | −4.6 (0.6) | −3.5 (−5, −2) |
| 30 ≤ BMI < 35 | −8.4 (0.7) | −3.1 (0.8) | −5.3 (−7.3, −3.4) | −7.4 (0.7) | −2.2 (0.8) | −5.2 (−7.2, −3.1) | −6.8 (0.7) | −3.2 (0.9) | −3.6 (−5.7, −1.5) | −7 (0.7) | −3.2 (0.9) | −3.8 (−6.1, −1.6) | |
| BMI ≥ 35 | −8.3 (0.9) | −3.1 (1) | −5.1 (−7.6, −2.6) | −6.9 (0.9) | −1.4 (1) | −5.5 (−7.9, −3) | −6.7 (0.9) | −4 (1.2) | −2.7 (−5.3, 0) | −6.4 (0.9) | −2.2 (1.2) | −4.2 (−7, −1.4) | |
| pvalue | 0.97 | 0.63 | 0.66 | 0.21 | <0.001 | 0.072 | 0.11 | 0.37 | 0.82 | 0.18 | 0.15 | 0.90 | |
| Low Back Pain Bothersomeness (0–6) (SE)¶¶ |
BMI < 30 | −2 (0.1) | −0.9 (0.1) | −1 (−1.4, −0.6) | −2.1 (0.1) | −1.1 (0.2) | −1.1 (−1.5, −0.7) | −2.1 (0.1) | −1 (0.2) | −1.1 (−1.5, −0.7) | −2 (0.1) | −1.2 (0.2) | −0.7 (−1.2, −0.2) |
| 30 ≤ BMI < 35 | −2.3 (0.2) | −1 (0.2) | −1.3 (−1.9, −0.7) | −2.1 (0.2) | −0.7 (0.2) | −1.4 (−2, −0.8) | −1.7 (0.2) | −1 (0.3) | −0.7 (−1.3, −0.1) | −1.5 (0.2) | −0.5 (0.3) | −1 (−1.7, −0.3) | |
| BMI ≥ 35 | −2.1 (0.3) | −0.2 (0.3) | −1.9 (−2.6, −1.2) | −1.8 (0.2) | −0.5 (0.3) | −1.3 (−2, −0.6) | −1.8 (0.3) | −0.4 (0.3) | −1.4 (−2.2, −0.6) | −1.6 (0.3) | −0.4 (0.3) | −1.3 (−2.1, −0.5) | |
| pvalue | 0.29 | 0.011 | 0.076 | 0.51 | 0.18 | 0.64 | 0.14 | 0.26 | 0.40 | 0.11 | 0.012 | 0.52 | |
| Very/somewhat satisfied with symptoms (%) |
BMI < 30 | 66.2 | 31.8 | 34.4 (24.1, 44.6) | 66.7 | 30.1 | 36.5 (25.9, 47.2) | 66.4 | 36.9 | 29.6 (17.9, 41.3) | 66.5 | 33.1 | 33.4 (20.8, 46) |
| 30 ≤ BMI < 35 | 70.5 | 26.7 | 43.8 (29, 58.7) | 75.4 | 23.6 | 51.8 (37, 66.5) | 69.3 | 39.6 | 29.7 (11.8, 47.6) | 59.1 | 30.5 | 28.6 (10, 47.2) | |
| BMI ≥ 35 | 75.7 | 14 | 61.7 (45.6, 77.9) | 73.1 | 23.3 | 49.8 (31.4, 68.2) | 59.7 | 21.8 | 37.8 (17, 58.7) | 61.9 | 26.3 | 35.7 (12.8, 58.6) | |
| pvalue | 0.44 | 0.13 | 0.057 | 0.31 | 0.60 | 0.21 | 0.54 | 0.36 | 0.79 | 0.58 | 0.84 | 0.90 | |
| Self-rated progress: major improvement (%) |
BMI < 30 | 66.5 | 28.8 | 37.7 (27.8, 47.6) | 61 | 32 | 29 (18.3, 39.8) | 61.9 | 33.4 | 28.5 (17.1, 39.9) | 56.8 | 30.3 | 26.5 (14.1, 38.9) |
| 30 ≤ BMI < 35 | 74.1 | 20.4 | 53.7 (40.2, 67.2) | 73.1 | 20.6 | 52.5 (38.3, 66.7) | 60.9 | 20.3 | 40.6 (25.1, 56.1) | 49.6 | 13.1 | 36.6 (21.3, 51.8) | |
| BMI ≥ 35 | 67 | 16 | 50.9 (33.2, 68.7) | 62.2 | 20 | 42.2 (23.7, 60.7) | 63.1 | 19.9 | 43.2 (23.4, 63) | 47.4 | 12.9 | 34.5 (14.7, 54.3) | |
| pvalue | 0.46 | 0.20 | 0.14 | 0.17 | 0.20 | 0.054 | 0.97 | 0.18 | 0.30 | 0.48 | 0.056 | 0.35 | |
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.
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
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.