Table 3.

As-treated analyses^*

Outcome	Lumbar fusion (N=62)	Cognitive/exercises (N=49)	Adjusted treatment effect (95% CI)†
Primary
Oswestry disability index‡
Baseline	44.4±10.6	43.0±11.1	−1.6 (−8.9 to 5.6)
4 Years	29.1±20.2	27.7±19.9
Secondary
General function score‡
Baseline	37.9±19.3	39.2±19.2	−3.2 (−11.4 to 5.0)
4 Years	24.8±24.7	22.5±22.9
Back pain‡
Baseline	63.3±14.7	64.2±12.5	4.1 (−4.7 to 12.8)
4 Years	40.5±23.0	46.8±23.4
Lower limb pain‡
Baseline	48.4±23.1	44.8±24.9	−2.9 (−12.6 to 6.7)
4 Years	35.5±27.7	32.7±26.8
Emotional distress§
Baseline	1.8±0.5	1.9±0.5	0.1 (−0.2 to 0.3)
4 Years	1.6±0.5	1.6±0.7
Life satisfaction¶
Baseline	5.0±2.3	4.7±1.7	0.2 (−0.6 to 1.0)
4 Years	6.4±2.4	6.2±2.4
Fear-avoidance physical activity**
Baseline	13.1±5.0	15.5±5.1	−2.8 (−5.3 to −0.4)
4 Years	8.8±7.0	7.3±6.4
Fear – avoidance work**
Baseline	26.4±10.1	28.1±12.4	−4.8 (−8.9 to −0.7)
4 Years	23.8±13.0	21.1±13.4
Patients overall rating – no (%) success††
1 Year	38 (61)	32 (65)	1.1 (0.8 to 1.8)
Work – no (%)
Baseline	8 (13)	9 (18)	0.8 (0.4 to 1.6)
1 Year	15 (26)	16 (33)

^*Mean values±SD unless otherwise noted.

^†The treatment effect is the difference between the lumbar fusion group and the cognitive intervention and exercises group at 4 years with adjustments for baseline score, age, gender and previous disc surgery. All patients randomly assigned (n=124) are included with last observed value carried forward.

^‡The Oswestry disability index, the general function score, back and lower limb pain ranges from 0 to 100, with lower scores indicating fewer symptoms.

^§Emotional stress ranges from 1 to 4, with lower scores indicating less severe symptoms.

^¶Life satisfaction ranges from 1 to 10, with higher scores indicating better life satisfaction.

^**Fear-avoidance beliefs for physical activity ranges from 0 to 24 and for work from 0 to 42, with lower scores indicating less strong beliefs for physical activity and work hurting the back.

^††All who did not attend the 4-year follow-up are classified as non-success.