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Table 4 Between-group comparisons in outcomes clustered by research design

From: Impact of contextual factors on patient outcomes following conservative low back pain treatment: systematic review

Ref no. (Year)
Design
[Grading]
CF-intervention Comparison condition(s) Between-group difference
Mean (SD)
Pain Intensity
Intervention’s influence: pain intensity Between-group difference
Mean (SD)
Physical functioning
Intervention’s influence:
Physical functioning
[35] (2011)
RCT
[Excellent]
Motivational Enhancement Treatment (MET) + PT: (n = 38) included proxy efficacy, treatment expectancy, therapeutic alliance, and empathy, combined with physical therapy PT (n = 38): 30-min physical therapy (PT) sessions for 8 weeks, including 15 min of interferential therapy and a tailored back exercise programme. Dummy MET included general communication (non-counselling) skills MET + PT
Post: M = 3.3 (± 2.1)
1-month: M = 3.1 (± 2.1)
PT only:
Post: M = 3.6 (± 2.4)
1-month: M = 3.9 (± 2.5)
MET + PT ~ PT
(p = .50)
95% C.I. [− 1.09 to 0.54]
MET + PT larger reduction in pain intensity than PT-alone but non-significant
MET + PT
Post: M = 6.3 (± 4.8)
1-month: M = 5.6 (± 4.5)
PT only
M = 7.2 (± 5.6)
1-month: M = 7.6 (± 6.4)
MET + PT ~ PT
(p = .424)
95% C.I. [− 2.83 to 1.44]
MET + PT larger reduction in physical disability than PT-alone but non-significant
[36] (2013)
RCT
[Excellent]
Cognitive Functional Therapy (CFT) (n = 51): focuses on reframing back pain in a person-centred manner along with altering maladaptive/unhelpful behaviours to normalise movement MT-EX (n = 43): consisted of manual therapy and exercise which included joint mobilisation or manipulation applied to the spine or pelvis; most patients (82.5%) were given exercises or a home exercise programme CFT
Post: M = 1.7 (± 1.7)
1-year: M = 2.3 (± 2.0)
MT-EX
Post: M = 3.8 (± 1.9)
1-year: M = 3.8 (± 2.1)
CFT > MT-EX
Post: (p < .001)
MDiff = − 2.1
95% C.I. [− 2.7 to − 1.4]
1-year: (p < .001)
MDiff = − 1.3
95% C.I. [− 2.1 to − 0.5]
Effect size unreported
CFT
Post: M = 7.6 (± 6.7)
1-year: M = 9.9 (± 9.8)
MT-EX
Post: M = 18.5 (± 8.1)
1-year:M = 19.7 (± 11.7)
CFT > MT-EX
Post: (p < .001)
MDiff = − 9.7
95% C.I. [− 12.7 to − 6.7]
1-year: (p < .001)
MDiff = − 8.2
95% C.I. [− 12.6 to − 3.8]
Effect size unreported
[37] (2014)
RCT (2 × 2)
[Excellent]
Enhanced versus limited therapeutic alliance (TA) following active or sham interferential current therapy (IFC) Variation of CFs:
Enhanced TA ( E ):
AE: Active IFC (n = 29)
SE: Sham IFC (n = 29)
Limited TA ( L ):
AL: Active IFC (n = 30)
SL: Sham IFC (n = 29)
Significant differences between the SL and the AL, AE & SE groups
Compared to SL (Sham IFC/Limited TA) mean differences were:
AE: MΔ = 2.3
SE: MΔ = 1.19
AL: MΔ = 0.8
( p  < .01)
Dose response
AE > SL: d = 2.51
Enhanced > Limited TA
SE > SL: d = 1.73
AE > AL: d = 1.36
Active > Sham IFC
AE > SE: d = 1.0
AL > SL: d = 0.89
Not applicable Not applicable
[38] (2022)
RCT
[Excellent]
PRT (n = 50): Pain Reprocessing Therapy (PRT) aims to shift patients’ beliefs about the causes and threat value of pain TAU (n = 50): Treatment as usual; Participants were given no additional treatment and agreed to continue their ongoing care as usual and not start new treatments before the post-treatment assessment PRT
Post: M = 1.18 (± 1.24)
1-year: M = 1.51 (± 1.59)
TAU
Post: M = 3.13 (± 1.45)
1-year: M = 3.0 (± 1.77)
PRT > TAU
Post: (p < .001)
g (SE) =  − 1.75 (0.24)
1-year: (p < .001)
g (SE) =  − 1.05 (0.24)
PRT
Post: M = 10.14 (± 10.6)
1-year: M = 11.16 (± 13.1)
TAU
Post: M = 20.68 (± 10.7)
1-year: M = 18.78 (± 12.6)
PRT > TAU
Post: (p < .001)
g (SE) =  − 1.70 (0.26)
1-year: (p < .001)
g (SE) =  − 0.83 (0.24)
[39] (2019)
RCT
[Excellent]
OLP (n = 63): Open-label placebo pills, social learning with TAU TAU (n = 59): Treatment as usual (TAU) patients received no intervention (no further description provided) OLP + TAU:
Post: MΔ = –0.62
(± SE = 0.23)
TAU:
Post: MΔ = 0.11
(± SE = 0.17)
OLP + TAU > TAU
Post: (p = .001)
d = –0.44
OLP + TAU:
Post: MΔ = 23.21
(SE ± 1.59)
TAU:
Post: MΔ = 0.65
(± SE = 1.15)
OLP + TAU > TAU
Post: (p = .02)
d = –0.45
[40] (2016)
RCT
[Excellent]
OLP (n = 41): Open-label placebo pills, verbal suggestions, social learning with TAU TAU (n = 42): Treatment as usual in an outpatient pain unit of a general public hospital (no further description of treatment provided) OLP + TAU:
MΔ = 1.49 (± 1.68)
TAU:
MΔ = 0.24 (± 1.61)
OLP + TAU > TAU
Post: (p < .001)
g = 0.76
OLP + TAU:
MΔ = 2.86 (± 3.91)
TAU:
MΔ = 0.02 (± 3.73)
OLP + TAU > TAU
Post: (p < .001)
g = 0.74
[41] (2017)
RCT (Cluster)
[Excellent]
Communication Style and Exercise Compliance in Physiotherapy (CONNECT) (n = 108): Enhancing physiotherapists’ communication skills to alter unhelpful patient beliefs and improve motivation TAU (n = 99): Treatment as usual; publicly funded physiotherapy with no restrictions on the number of sessions or the type of treatment the physiotherapist administered CONNECT
Post:
MΔ = − 1.53 (± 2.71)
24 weeks:
MΔ = − 1.53 (± 2.78)
TAU
Post:
MΔ = − 1.31 (± 2.36)
24 weeks:
MΔ = − 1.18 (± 3.19)
CONNECT ~ TAU
(p = .75)
MDiff = − 0.10
95% C.I. [− 0.71 to 0.51]
d = − 0.04
CONNECT
Post:
MΔ = − 3.48 (± 5.72)
24 weeks:
MΔ = − 4.87 (± 5.86)
TAU
Post:
MΔ = − 2.82 (± 5.77)
24 weeks:
MΔ = − 4.09 (± 5.95)
CONNECT a  ~ TAU
(p = .60)
MDiff = − 0.36
95% C.I. [− 1.68–0.96]
d = − 0.08
[42] (2010)
RCT
[Good]
ED (n = 18): Pain biology education for the management of cLBP Variation of CFs:
ED-EX (n = 20): Pain biology education plus six weekly exercise sessions (in a group format)
ED
Post: MΔ = − 30.9
ED-EX
Post: MΔ = − 4.2
ED > ED-EX
(p = .025)
ED
Post: MΔ = − 7.5
ED-EX
Post: MΔ = − 3.8
ED ~ ED-EX
(p = .127)
[43] (2020)
RCT
[Good]
OLP (n = 26): Open-label placebo pills, verbal suggestions, with TAU (advice, education, reassurance, self-management) TAU (n = 26): Treatment as usual included advice to remain active, along with education and reassurance in addition to a psychological education self-management strategy to improve pain-related disabilities OLP + TAU:
Post:
MΔ = –0.9 (± 1.8)
12-weeks:
MΔ = –1.1 (± 1.9)
TAU:
Post:
MΔ = –0.2 (± 1.8)
12-weeks:
MΔ = –0.8 (± 1.9)
OLP + TAU ~ TAU
Post: (p = .19)
d = 0.38
12-weeks: (p = .18)
ηp2 = 0.04
OLP + TAU:
RMDQ: MΔ = –2.2 (± 2 .9) TUG: MΔ = –0.7 (± 1.0)
12-weeks:
RMDQ: MΔ = –3.3 (± 3.2)
TUG: MΔ = –0.62 (± 1.5)
TAU:
RMDQ: MΔ = –1.4 (± 3.6)
TUG: MΔ = –0.7 (± 1.5)
12-weeks:
RMDQ: MΔ = –2.3 (± 3.2)
TUG: MΔ = –1.1 (± 1.1)
OLP + TAU ~ TAU
RMDQ: (p = .40)
d = 0.24
TUG: (p = .98)
d = 0.01
12-weeks
RMDQ: (p = .37)
ηp2 = 0.02
TUG: (p = .28)
ηp2 = 0.03
[44] (2021)
RCT
[Good]
ED + TA (n = 74): Patient education (ED) relating to return to daily activities, advice on coping with pain, a clear explanation of signs and symptoms with an emphasis on increasing empathy and therapeutic alliance (TA) Variation of CFs:
ED only (n = 74): the same structured patient education sessions (ED) but with no emphasis on enhancing the patient-practitioner relationship
No ED (n = 74): Patients received no-education and were advised not to seek treatment in the first month after randomisation
ED + TA vs ED only
Post: MDiff = 0.09
6-mo: MDiff = 0.61
1-year: MDiff = − 0.02
ED + TA vs No ED
Post: MDiff = 0.06
6-mo: MDiff = − 0.05
1-year: MDiff = 1.40
ED only vs No ED:
Post: MDiff = 0.15
6-mo: MDiff = 0.55
1-year: MDiff = 1.37
ED + TA ~ ED only
ns: (p-values unreported)
ED + TA > No ED
1-year: (p < .05)
Post & 6-months: ns
ED only > No ED
1-year: (p < .05)
Post & 6-months: ns
Effect sizes unreported
M Diff PSFS/ODI
ED + TA vs ED only
Post: MDiff = 0.46/1.90
6-mo:MDiff = 0.52/1.27
1-yr: MDiff = 0.40/2.26
ED + TA vs No ED
Post: MDiff = − 1.41/4.39
6-mo:MDiff = − 1.21/5.30
1-yr: MDiff = − 1.69/9.26
ED only vs No ED
Post: MDiff = − 0.95/2.48
6-mo:MDiff = − 0.68/4.02
1-yr: MDiff = − 1.29/7.00
ED + TA ~ ED only
ns: (p-values unreported)
ED + TA > No ED
PSFS: ( p  < .05)
Post, 6-months, 1-year
ODI: ( p  < .05)
6-months, 1-year
ED only > No ED
PSFS: ( p  < .05)
Post, 1-year
ODI: ( p  < .05)
1-year
Effect sizes unreported
[45] (2017)
RCT
(2 × 2)
[Good]
Manipulating patient’s pain expectations using an inert solution/labelling, verbal instructions, and classical conditioning (CC) Variation of CFs:
Opioid Instruction (OI) (Deceptive/Hidden)
With CC: (n = 12)
No CC: (n = 12)
Placebo Instruction (PI)
(Truthful/Open-Label)
With CC: (n = 12)
No CC: (n = 12)
Post: (Day 1)
Opioid Instruction
With CC:
M = 1.92 (± 1.73)
No CC:
M = 3.00 (± 2.73)
Placebo Instruction:
With CC:
M = 4.58 (± 2.31)
No CC:
M = 5.83 (± 1.95)
Deception > Truth
( p  =  < .01)*
Dose–response:
Deception (OI)
With CC: d = 1.83*
No CC: d = 0.83*
Truthful (PI)
With CC: d = 0.32; ns
No CC: d = − 0.64*
(nocebo effect)
Post: (Day 1)
Opioid Instruction
With CC:
M = 77.22 (± 15.43)
No CC:
M = 67.78 (± 29.24)
Placebo Instruction:
With CC:
M = 53.89 (± 24.03)
No CC:
M = 44.44 (± 15.66)
Deception > Truth
( p  =  < .01)*
Dose–response:
Deceptive: (OI)
With CC: d = − 0.92*
No CC: d = − 0.59*
Truthful: (PI)
With CC: d = − 0.17
No CC: d = 0.43
[46] (2019)
RCT
(2 × 2)
[Good]
Manipulating patient’s pain expectations using an inert drain dressing infusion with mirrors/labelling, verbal instructions, and either placebo or nocebo conditioning (PC or NC) Variation of CFs:
Sham “Opioid” Infusion:
Placebo Conditioning (PC): (n = 17)
Sham only (SO): (n = 21)
Nocebo Conditioning (NC): (n = 21)
Natural History (NH): (n = 14) no sham infusion (waiting only) nor any classical conditioning
Post infusion: (Day 1)
PC: M = 3.24 (± 2.48)
SO: M = 2.43 (± 1.88)
NC: M = 3.57 (± 2.27)
NH: M = 5.00 (± 2.35)
Post infusion: (Day 8)
PC: M = 3.41 (± 2.52)
SO: M = 2.57 (± 2.22)
NC: M = 3.48 (± 2.18)
NH: M = 5.36 (± 1.98)
Sham Infusion > NH
PC & SO ( p  =  < .001)
NC ( p  =  < .01)
PC: η2 = 0.38
SO: η2 = 0.56
NC: η2 = 0.21
NH: ( p  = .92)
NH: η2 = 0.01
Post infusion: (Day 1)
PC: M = 72.54 (± 29.2)
SO: M = 77.46 (± 21.4)
NC: M = 73.33 (± 23.2)
NH: M = 54.76 (± 23.7)
Post infusion: (Day 8)
PC: M = 76.86 (± 29.2)
SO: M = 78.73 (± 22.5)
NC: M = 78.73 (± 18.0)
NH: M = 53.86 (± 23.0)
Sham Infusion > NH
SO ( p  =  < .01)
PC & NC ( p  =  < .05)
PC: η2 = 0.15
SO: η2 = 0.27
NC: η2 = 0.20
NH: ( p  = .63)
NH: η2 = 0.03
[47] (2017)
CCT
[Excellent]
Enhanced Transtheoretical Model Intervention (ETMI) (n = 94): focusing on therapists’ communication skills; improving TA using empathy, active listening; addressing low motivation, self-efficacy, and addressing maladaptive beliefs/behaviours Conventional physical therapy (PT (n = 95)) treatments: mobilisation, manipulation, back exercises, postural training, back school, electrical stimulation, shortwave diathermy, cooling, and stretching Average Pain
Post: MΔ = 0.6
95% C.I. [− 0.2 to 1.4]
Follow-up: MΔ = 0.9
95% C.I. [− 0.03 to 1.8]
Worst Pain
Post: MΔ = 0.10
95% C.I. [− 0.8 to 1.2]
Follow-up: MΔ = 1.2
95% C.I. [0.05 to 2.3]
ETMI ~ PT
Post: (p = .10)
Follow-up: (p = .06)
Worst pain
ETMI > PT
Post: (p = .70)
Follow-up: (p = .04)
Effect size unreported
Post: MΔ = 1.3,
95% C.I. [− 0.3 to 3.0]
Follow-up: MΔ = 2.7
95% C.I. [0.9 to 4.5]
ETMI ~ PT
Post: (p = .10)
ETMI > PT
Follow-up: (p = .004)
d = 0.54
[48] (2012)
CCT
[Good]
Intervention (n = 93) focused on patient’s illness and treatment beliefs and their information needs TAU (n = 95): Treatment as usual; inpatient musculoskeletal rehabilitation which is typically multimodal and multidisciplinary Intervention
M = 42.91 (± 21.50)
TAU
M = 42.26 (± 20.77)
Intervention ~ TAU
(p = .319)
Intervention
M = 30.98 (± 15.70)
Control
M = 31.46 (± 16.19)
Intervention ~ TAU
(p = .412)
[49] (2018)
CCT
[Fair]
Adding one weekly group-based physical therapy session in a rehabilitation setting compared to home treatment alone Variation of CFs:
Rehab (n = 13): Weekly group-based physical therapy session involving exercises
Home (n = 17): No physical therapy supervision
Post-treatment
MDiff = − 0.9
95% C.I. [− 2.3 to 0.5]
Rehab ~ Home
(p = .655)
Post-treatment
MDiff = − 0.2
95% C.I. [− 3.8 to 3.3]
Rehab ~ Home
(p > 0.999)
  1.  ~ indicates equivalence between groups; ns: not statistically significant; 95% C.I.: 95% Confidence Interval; TUG: Timed-Up-and-Go (measured in seconds); RMDQ: Roland–Morris Disability Questionnaire – where higher scores represent higher levels of physical disability. PSFS: Patient-Specific Functional Scale – where higher scores represent higher levels of functioning; ODI: Oswestry Disability Index – where higher scores represent higher levels of physical disability
  2. aThis RCT involved three arms, including an open-label placebo (OLP) group. However, the OLP involved the administration of an injection rather than pills/capsules. These results were therefore excluded from the synthesis since it is an invasive procedure (exclusion criteria) and was not directly comparable to the other OLP trials
  3. bSex moderated the effect. Women in the CONNECT arm improved 4.94 RMDQ points compared to women in the control group