'Which treatment do you believe you received?' A randomised blinding feasibility trial of spinal manual therapy

Table 2 Primary and secondary outcomes

Outcome	Active SMT (n = 40)	Placebo SMT (n = 41)	Overall (95% CI)
Primary outcome
Bang BI of participants—study visit 1^a	0.50 (0.26 to 0.74)	0.37 (0.10 to 0.63)	Sum BI, 0.87 (0.51 to 1.23)
Bang BI of participants—study visit 2^a	0.36 (0.08 to 0.64)	0.29 (0.01 to 0.57)	Sum BI, 0.65 (0.26 to 1.04)
Secondary outcomes
James BI of participants—study visit 1^b			0.35 (0.24 to 0.45)
James BI of participants—study visit 2^b			0.37 (0.27 to 0.48)
Bang BI of outcome assessors—study visit 1^c	0.08 (− 0.05 to 0.20)	− 0.12 (− 0.24 to − 0.00)	Sum BI, − 0.04 (− 0.22 to 0.14)
Bang BI of outcome assessors—study visit 2^c	0.03 (− 0.11 to 0.16)	− 0.07 (− 0.21 to 0.07)	Sum BI, − 0.04 (− 0.23 to 0.15)
James BI of outcome assessors—study visit 1^c			0.93 (0.87 to 0.98)
James BI of outcome assessors —study visit 2^c			0.91 (0.85 to 0.97)

Other participant outcomes	Active SMT (n = 40)	Placebo SMT (n = 41)	Effect (95% CI)
Credibility—study visit 2, mean (SD)^d	6.40 (1.76)	4.91 (2.50)	MD, 1.49 (0.55 to 2.43)
Expectancy—study visit 2, mean (SD)^e	6.17 (1.65)	4.84 (2.54)	MD, 1.33 (0.40 to 2.26)
Credibility/Expectancy—study visit 2, mean (SD)^f	6.29 (1.66)	4.87 (2.49)	MD, 1.42 (0.50 to 2.34)
Change in ROM—degrees, mean (SD)^g
Flexion	− 2.72 (11.65)	0.07 (10.36)	MD, − 2.79 (− 7.63 to 2.05)
Extension	− 0.03 (6.39)	0.73 (8.57)	MD, − 0.76 (− 4.06 to 2.54)
Total	− 2.74 (13.98)	0.80 (14.99)	MD, − 3.54 (− 9.89 to 2.81)

BI blinding index, CEQ Credibility/Expectancy Questionnaire, MD mean difference
^aFrom responses to the questions 'Which treatment do you believe you received?'; Bang BI ranges from –1 (all incorrect beliefs) to 1 (all correct beliefs); values between − 0.3 and 0.3 may be suggestive of 'adequate' blinding
^bFrom responses to the question 'Which treatment do you believe you received?'; James BI ranges from 0 (all correct beliefs) to 1 (all 'Do not know' beliefs); when 50% of beliefs are correct, and 50% incorrect, James BI returns 0.5
^cFrom responses to the question 'Which treatment do you believe this participant received?'
^dCredibility subcomponent of the CEQ (items 1 to 3) [24]; ranges from 1 (least credible) to 9 (most credible)
^eExpectancy subcomponent of the CEQ (items 4 to 6) [24]; ranges from 1 (lowest expectancy) to 9 (highest expectancy)
^fCredibility and expectancy subcomponents of the CEQ, combined [24] (items 1 to 6); ranges from 1 (least credible and lowest expectancy) to 9 (most credible and highest expectancy)
^gChange in device-measured observer-reported ROM measurements between baseline and post-study visit 2 using the iOS application Measure® (iOS version 16.0.2, iPhone® model X, Apple Inc., California, United States) [24]; higher positive values indicate larger positive change in ROM

ISSN: 2045-709X