Placebo effects in trials evaluating 12 selected minimally invasive interventions: a systematic review and meta-analysis

doi:10.1136/bmjopen-2014-007331

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BMJ Open. 2015; 5(1): e007331.

Published online 2015 Jan 30. doi: 10.1136/bmjopen-2014-007331

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Table 2

Effect size (ES) on primary and pooled secondary end points, showing differences between active treatment and sham arms.

Author/procedure	Limit disease duration/time to follow-up (months)	Trial arm/number of patients randomised	ES primary end point	ES pooled secondary end points (number of end points)
Leon 2005/percutaneous myocardial laser revascularisation	None/12		Exercise duration (s)	(10)
		Active/98	0.23	0.60
		Sham/102	0.22	0.54
ES active treatment vs sham			0.01	0.07
Salem 2004/percutaneous myocardial laser revascularisation	None/12		Exercise duration (s)	–
		Active/40	0.04
		Sham/42	0.08
ES active treatment vs sham			−0.04
Sihvonen 2013/arthroscopic partial meniscectomy	>3/12		Lysholm knee score	(4)
		Active/70	0.86	0.58
		Sham/76	1.03	0.58
ES active treatment vs sham			−0.17	0.00
Moseley 2002/arthroscopic debridement	None/12		Knee Specific Pain Scale	(5)
		Active/59	0.54	0.11
		Sham/60	0.85	0.20
ES active treatment vs sham			−0.31	−0.09
Pham 2004/hyaluronic acid			VAS pain	(3)
	None/12	Active/131	1.48	1.35
		Sham/85	1.54	1.30
ES active treatment vs sham			−0.06	0.05
Chevalier 2010/hyaluronic acid			Womac A	Womac C function
	None/6	Active/124	1.52	1.13
		Sham/129	1.18	1.07
ES active treatment vs sham			0.34	0.06
Altman 2004/hyaluronic acid	None/6		Womac pain	(2)
		Active/172	0.76	0.38
		Sham/174	0.85	0.53
ES active treatment vs sham			−0.09	−0.15
Kallmes 2009/percutaneous vertebroplasty	<12/1		Roland-Morris Disability Questionnaire	(7)
		Active/68	0.86	0.72
		Sham/63	0.81	0.63
ES active treatment vs sham			0.05	0.09
Buchbinder 2009/percutaneous vertebroplasty	<12/6		Pain Score	(4)
		Active/38	0.83	0.46
		Sham/40	0.71	0.51
ES active treatment vs sham			0.12	−0.05
Cohen 2012/epidural injection of corticosteroids	<6 /1		NRS leg pain	(2)
		Active/28	1.51	0.88
		Sham/30	0.82	0.39
ES active treatment vs sham			0.69	0.49
Iversen 2011/epidural injection of corticosteroids	>3/12		Oswestry Disability Index	–
		Active/36	1.68
		Sham/40	1.85
ES active treatment vs sham			−0.17
Arden 2005/epidural injection of corticosteroids	>1<18/12		Oswestry Disability Index	(2)
		Active /120	1.42	1.14
		Sham/108	1.44	1.21
ES active treatment vs sham			−0.02	−0.07
Valat 2002/epidural injection of corticosteroids	<6/1		VAS Pain	(3)
		Active/42	1.85	1.10
		Sham/43	1.47	0.99
ES active treatment vs sham			0.38	0.10
Freeman 2005/intradiscal electrothermal therapy	≥3/6		Oswestry Disability Index	(6)
		Active/38	0.10	−0.03
		Sham/19	−0.07	0.12
ES active treatment vs sham			0.17	−0.15
Pauza 2003/intradiscal electrothermal therapy	>6/6		Oswestry Disability Index	(3)
		Active/32	0.94	0.90
		Sham/24	0.35	0.46
ES active treatment vs sham			0.59	0.44
Kvarstein 2009/percutaneous intradiscal radiofrequency thermocoagulation	>6/12		Brief Pain Inventory	(5)
		Active/10	0.34	0.54
		Sham/10	0.23	0.24
ES active treatment vs sham			0.11	0.30
Olanow 2003/fetal nigral transplantation	None/24		UPDRS 3 off	(5)
		Active/12	0.04	−0.24
		Sham/11	−0.44	−0.19
ES active treatment vs sham			0.48	−0.06
Marks 2010/gene delivery of AAV2-neurturin	≥60/12		UPDRS 3 off	(7)
		Active/38	0.72	0.23
		Sham/20	0.53	−0.05
ES active treatment vs sham			0.19	0.28
Gross 2011/transplantation of human retinal pigmental cells	≥60/12		UPDRS 3 off	(2)
		Active/35	1.09	0.08
		Sham/36	0.88	0.06
ES active treatment vs sham			0.21	0.02
LeWitt 2011/AAV-GAD gene into subthalamic nucleus	≥60/6		UPDRS 3 off	(7)
		Active/16	1.00	0.30
		Sham/21	0.42	0.21
ES active treatment vs sham			0.58	0.08
Dowson 2008/patent foramen ovale closure	None/6		Frequency migraine/month (per protocol)	Headache Impact Test
		Active/74	0.74	1.02
		Sham/73	0.45	1.06
ES active treatment vs sham			0.28	0.04

NRS, Numerical Rating Scale; UPDRS, Unified Parkinson's Disease Rating Scale; VAS, visual analogue scale; Womac, Western Ontario and McMaster Universities Osteoarthritis Index.