Table 3

Formal comparisons between therapy arms and TAU*

	TCBT versus TAU				WCBT versus TAU
	Estimated difference	95% CI	Test (df) P value	Standardised difference†	Estimated difference	95% CI	Test (df) P value	Standardised difference†
IBS-SSS
3 months	−69.2	−88.7 to −49.7	t=−7.0 (367) <0.001	0.73	−53.0	−74.9 to −31.1	t=−4.7 (237) <0.001	0.56
6 months	−58.3	−80.3 to −36.3	t=−5.2 (295) <0.001	0.61	−35.7	−58.5 to −12.9	t=−3.1 (257) 0.002	0.37
12 months‡	−61.6	−89.5 to −33.8	t=−4.3 (1581) <0.001	0.65	−35.2	−57.8 to −12.6	t=− 3.1 (275) 0.002	0.37
WSAS
3 months	−3.4	−4.8 to −2.0	t=−4.8 (355) <0.001	0.40	−3.0	−4.4 to −1.5	t=−3.9 (288) <0.001	0.35
6 months	−2.7	−4.2 to −1.2	t=−3.6 (280) <0.001	0.32	−2.5	−4.0 to −1.0	t=−3.3 (257) 0.001	0.30
12 months	−3.5	−5.1 to −1.9	t=−4.2 (268) <0.001	0.41	−3.0	−4.6 to −1.3	t=−3.5 (258) 0.001	0.35
HADS
3 months	−2.1	−3.2 to −0.9	t=−3.6 (306) <0.001	0.30	−2.5	−3.7 to −1.3	t=−4.0 (261) <0.001	0.36
6 months	−2.2	−3.5 to −0.8	t=−3.2 (227) 0.002	0.32	−2.9	−4.2 to −1.6	t=−4.2 (230) <0.001	0.42
12 months	−2.8	−4.1 to −1.5	t=−4.3 (248) <0.001	0.41	−2.3	−3.7 to −1.0	t=−3.4 (217) 0.001	0.34

	Estimated OR	95% CI	Test (df) P value		Estimated OR	95% CI	Test (df) P value
PEQ responders
3 months	13.3	6.9 to 25.8	t=7.7 (1347) <0.001		6.6	3.3 to 13.2	t=5.4 (918) <0.001
6 months	11.6	6.4 to 20.9	t=8.1 (1134) <0.001		4.8	2.7 to 8.7	t=5.2 (889) <0·001
12 months‡	9.3§	4.5 to 19.3	t=6.0 (2369) <0.001		3.5	2.0 to 5.9	t=4.5 (1079) <0.001
SGA responders
3 months	10.2	5.8 to 18.1	t=8.1 (1289) <0.001		6.4	3.6 to 11.3	t=6.3 (824) <0.001
6 months	6.2	3.7 to 10.4	t=6.9 (1637) <0.001		5.0	2.8 to 8.8	t=5.6 (630) <0.001
12 months‡	6.1¶	2.5 to 15.0	t=3.9 (2957) <0.001		3.6	2.0 to 6.3	t=4.4 (600) <0.001

*All inferences were derived by multiple imputation as described in the Methods section. Each model used 100 imputations.
†Differences were standardised by dividing by baseline SD for IBS-SS (95.5), WSAS (8.8) and HADS (6.9), respectively.
‡The 12-month model included therapist effects in the TCBT arm.
§The reported TCBT effect is a conditional effect (conditioned on therapist). The corresponding marginal ORs within site are 9.0 (Southampton GP Practices), 9.2 (Southampton Secondary Care), 9.3 (London GP Practices) and 9.3 (London Secondary Care).
¶The reported TCBT effect is a conditional effect (conditioned on therapist). The corresponding marginal ORs within site are 5.8 (Southampton GP Practices), 6.0 (Southampton Secondary Care), 5.9 (London GP Practices) and 5.9 (London Secondary Care).
HADS, Hospital Anxiety and Depression Scale; IBS-SSS, IBS Symptom Severity Score; PEQ, Patient Enablement Questionnaire; SGA, Subject’s Global Assessment of Relief; TAU, treatment as usual; TCBT, telephone-delivered CBT; WCBT, web-based CBT; WSAS, Work and Social Adjustment Scale.