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. Author manuscript; available in PMC: 2012 Dec 1.
Published in final edited form as: Spine (Phila Pa 1976). 2011 Dec 1;36(25):2197–2210. doi: 10.1097/BRS.0b013e3182341edf

Table 7.

Subgroup results from adjusted* as-treated outcome analysis by two groups duration of symptoms (One year or less vs. More than one year) for the randomized and observational cohorts combined patients with lumbar degenerative spondylolisthesis.

Outcome
 Duration of
Symptoms		 1-Year
 2-Year
 3-Year
 4-Year
DS Surgical Non-
operative		 Treatment
Effect†
(95% CI)		 Surgical Non-
operative		 Treatment
Effect†
(95% CI)		 Surgical Non-
operative		 Treatment
Effect†
(95% CI)		 Surgical Non-
perative		 Treatment
Effect†
(95% CI)
Primary
Outcomes
SF-36 Bodily
Pain (BP)
(0–100) (SE)		 One year or
less		 34.8 (1.8) 14 (1.7) 20.8
(16, 25.5)		 32.4 (1.8) 14 (1.9) 18.4
(13.4, 23.5)		 34.3 (1.8) 16.1 (2) 18.2
(12.9, 23.5)		 32.2 (1.9) 16.2 (2.2) 16
(10.3, 21.7)
More than 1
year		 30.3 (1.7) 13.3 (2.5) 17
(11.3, 22.6)		 31.2 (1.6) 11.3 (2.6) 19.9
(14.1, 25.7)		 30.7 (1.6) 13.3 (2.9) 17.4
(11.1, 23.7)		 29.9 (1.8) 15 (3) 14.9
(8.3, 21.5)
pvalue 0.065 0.81 0.31 0.59 0.40 0.71 0.12 0.42 0.84 0.35 0.73 0.80
SF-36 Physical
Function (PF)
(0–100) (SE)		 One year or
less		 29.3 (1.7) 11.6 (1.6) 17.7
(13.2, 22.3)		 25.7 (1.7) 10 (1.8) 15.7
(10.9, 20.5)		 24.9 (1.8) 9.9 (1.9) 15.1
(10, 20.1)		 26.6 (1.9) 8.9 (2.1) 17.6
(12.2, 23.1)
More than 1
year		 27.2 (1.7) 9 (2.4) 18.1
(12.8, 23.5)		 25.9 (1.6) 8.6 (2.5) 17.3
(11.8, 22.8)		 25 (1.6) 7.3 (2.8) 17.7
(11.7, 23.7)		 25.8 (1.7) 6.9 (2.9) 18.8
(12.5, 25.1)
pvalue 0.37 0.36 0.90 0.93 0.64 0.66 0.97 0.45 0.51 0.74 0.57 0.78
Mental
Component
Summary (MCS)
(0–100) (SE)		 One year or
Less		 3.4 (0.7) 1.7 (0.7) 1.8
(−0.2, 3.8)		 2.8 (0.7) 1.3 (0.8) 1.5
(−0.6, 3.6)		 2.1 (0.8) 0.3 (0.8) 1.7
(−0.5, 4)		 2.5 (0.8) 1 (1) 1.5
(−1, 4)
More than 1
year		 2.5 (0.7) 1 (1) 1.5
(−0.9, 3.9)		 2.4 (0.7) 0 (1.1) 2.4
(−0.1, 4.9)		 2.9 (0.7) −0.2 (1.2) 3.1
(0.4, 5.8)		 2.1 (0.8) −1.6 (1.3) 3.7
(0.7, 6.6)
pvalue 0.36 0.61 0.85 0.73 0.35 0.57 0.39 0.73 0.44 0.76 0.12 0.26
Oswestry
Disability Index
(ODI) (0–100)
(SE)		 One year or
less		 −26.8 (1.3) −8.1 (1.3) −18.7
(−22.3, −15.2)		 −24.5 (1.3) −8.6 (1.4) −16
(−19.7, −12.2)		 −23.1 (1.4) −10.5 (1.5) −12.6
(−16.5, −8.7)		 −23.6 (1.4) −9.8 (1.6) −13.8
(−18, −9.6)
More than 1
year		 −23.3 (1.3) −6.6 (1.9) −16.7
(−20.9, −12.6)		 −23.5 (1.2) −6 (2) −17.5
(−21.8, −13.1)		 −20.9 (1.2) −5.6 (2.2) −15.3
(−20, −10.6)		 −22.1 (1.3) −6 (2.2) −16.2
(−21, −11.3)
pvalue 0.055 0.48 0.48 0.54 0.29 0.60 0.20 0.063 0.39 0.44 0.16 0.46
Secondary
Outcomes
Stenosis
Bothersomeness
Index (0–24)
(SE)		 One year or
less		 −9.5 (0.5) −3.9 (0.5) −5.6 (−7, −4.2) −9 (0.5) −4.2 (0.5) −4.8
(−6.2, −3.3)		 −9.4 (0.5) −4.6 (0.6) −4.9
(−6.4, −3.3)		 −9.1 (0.5) −4.2 (0.6) −4.8
(−6.5, −3.2)
More than 1
year		 −9.5 (0.5) −4 (0.7) −5.5 (−7, −4) −9.1 (0.4) −3.3 (0.7) −5.8
(−7.4, −4.2)		 −8.8 (0.5) −3.7 (0.8) −5.1
(−6.8, −3.3)		 −9.1 (0.5) −2.7 (0.8) −6.4
(−8.2, −4.6)
pvalue 0.98 0.90 0.91 0.89 0.30 0.36 0.35 0.40 0.87 0.90 0.15 0.20
Low Back Pain
Bothersomeness
(0–6) (SE)		 One year or
less		 −2.3 (0.1) −1.1 (0.1) −1.2
(−1.6, −0.8)		 −2.1 (0.1) −1.4 (0.1) −0.8
(−1.2, −0.4)		 −2.2 (0.1) −1.5 (0.2) −0.7
(−1.1, −0.3)		 −2.1 (0.2) −1.2 (0.2) −0.9
(−1.4, −0.4)
More than 1
year		 −2.4 (0.1) −1.1 (0.2) −1.3
(−1.7, −0.9)		 −2.1 (0.1) −0.9 (0.2) −1.3
(−1.8, −0.8)		 −2 (0.1) −1.1 (0.2) −0.9
(−1.4, −0.4)		 −2 (0.1) −1 (0.2) −1.1
(−1.6, −0.6)
pvalue 0.80 0.93 0.91 0.93 0.032 0.11 0.28 0.16 0.64 0.66 0.39 0.67
Leg pain
(0–6) (SE)		 One year or
less		 −3 (0.2) −1.5 (0.1) −1.5
(−1.9, −1.1)		 −2.8 (0.2) −1.6 (0.2) −1.3
(−1.8, −0.8)		 −3 (0.2) −1.7 (0.2) −1.3
(−1.8, −0.8)		 −3.1 (0.2) −1.7 (0.2) −1.4
(−1.9, −0.9)
More than
one year		 −3.1 (0.1) −1.4 (0.2) −1.6
(−2.1, −1.1)		 −3 (0.1) −1.2 (0.2) −1.8
(−2.3, −1.3)		 −2.9 (0.1) −1.5 (0.2) −1.4 (−2, −0.8) −3 (0.2) −1.2 (0.3) −1.8
(−2.4, −1.2)
pvalue 0.86 0.77 0.72 0.48 0.087 0.074 0.61 0.55 0.83 0.63 0.15 0.34
Very/somewhat
satisfied with
symptoms (%)		 One year or
less		 76.4 31.8 44.6
(34.6, 54.7)		 73.3 35.9 37.5
(26.3, 48.6)		 69.5 39.5 30
(17.7, 42.3)		 66.6 29.7 36.9
(24.2, 49.6)
More than 1
year		 69.3 16.5 52.8
(42, 63.7)		 65.7 24.5 41.2
(28.7, 53.7)		 63 28.5 34.5
(20.4, 48.6)		 60.3 28.4 32
(16.6, 47.3)
pvalue 0.19 0.024 0.29 0.15 0.15 0.69 0.25 0.21 0.67 0.31 0.89 0.70
Self-rated
pogress major
mprovement (%)		 One year or
less		 78.2 28.2 50
(40.2, 59.8)		 72 26.8 45.2
(34.4, 56)		 73.9 28.4 45.5
(34.1, 56.8)		 68.3 27.9 40.5
(27.8, 53.1)
More than 1
year		 72.6 19.8 52.8
(41.4, 64.2)		 73.8 17.8 56.1
(44.8, 67.3)		 67.5 18.5 49.1
(36.5, 61.7)		 63.7 9.1 54.7
(43.4, 66)
pvalue 0.29 0.23 0.73 0.72 0.20 0.20 0.25 0.25 0.64 0.45 0.052 0.12
*

Adjusted for age, gender, BMI, 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.

**

Other comorbidities include: stroke, cancer, fibromyalgia, cfs, PTSD, alcohol, drug dependency, lung, liver, kidney, blood vessel, nervous system, migraine, anxiety

†

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.