Table 2.

Primary and secondary continuous outcomes^a in placebo (n = 103) and intervention (n = 102) groups

	Placebo, mean (SD)			Nortriptyline, mean (SD)			Baseline-adjusted difference at 14 weeks

	Baseline	14 weeks	Change	Baseline	14 weeks	Change	Difference	95% CI	P-value
Primary outcome
Pain (WOMAC)^b	61.2 (12.5)	42.5 (24.0)	−18.7 (25.8)	60.2 (13.5)	36.0 (23.2)	−24.3 (22.5)	−6.2	−0.26 to 12.56	0.06

Secondary outcomes
Function (WOMAC)^b	59.9 (14.8)	41.9 (24.2)	−18.0 (23.2)	62.8 (15.0)	39.6 (24.4)	−23.2 (21.5)	−4.4	−10.48 to 1.79	0.16
Stiffness (WOMAC)^b	61.2 (20.1)	47.2 (27.9)	−14.0 (29.5)	65.2 (20.3)	45.4 (27.4)	−19.9 (27.4)	−3.6	−10.94 to 3.72	0.33
Global assessment VAS^b	72.6 (21.1)	53.6 (28.6)	−19.0 (33.0)	74.3 (20.2)	49.3 (30.8)	−25.0 (33.5)	−4.7	−12.91 to 3.46	0.26

Quality of life^c
Physical function	31.6 (9.9)	31.0 (10.1)	−0.6 (8.8)	29.9 (10.6)	31.9 (11.5)	2.0 (10.0)	2.0	−0.39 to 4.43	0.10
Role limitations due to physical health	39.7 (11.1)	39.7 (12.1)	−0.1 (11.5)	39.9 (11.0)	41.7 (11.9)	1.8 (11.9)	2.0	−0.95 to 4.88	0.19
Bodily pain	35.5 (7.5)	38.6 (8.8)	3.1 (9.4)	35.7 (8.1)	41.4 (10.0)	5.8 (8.8)	2.8	0.42 to 5.08	0.02
General health	46.1 (8.6)	46.7 (10.1)	0.6 (7.8)	47.4 (8.4)	47.4 (8.7)	0.1 (7.3)	−0.1	−2.15 to 1.88	0.90
Energy and vitality	47.1 (10.0)	47.1 (10.8)	0.0 (9.9)	46.2 (8.8)	46.8 (10.9)	0.6 (8.5)	0.3	−2.15 to 2.72	0.82
Social function	44.8 (11.4)	43.2 (13.5)	−1.6 (12.8)	44.7 (11.5)	45.0 (12.7)	0.4 (13.2)	1.9	−1.40 to 5.14	0.26
Role limitations due to emotional health	47.8 (11.4)	44.7 (12.9)	−3.1 (13.9)	47.3 (11.8)	46.0 (12.9)	−1.3 (11.8)	1.6	−1.63 to 4.79	0.33
Emotional wellbeing	52.1 (8.8)	51.7 (10.0)	−0.4 (8.9)	51.9 (9.1)	51.4 (10.9)	−0.6 (9.7)	−0.2	−2.66 to 2.21	0.86

↵a All outcomes have been standardised to a range of 0–100.
↵b 0 = best-possible outcome.
↵c 100 = best-possible outcome. SD = standard deviation. VAS = visual analogue scale. WOMAC = McMaster Universities Osteoarthritis Index.