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BMJ Open. 2015 Dec 11;5(12):e009655. doi: 10.1136/bmjopen-2015-009655.

To what extent are surgery and invasive procedures effective beyond a placebo response? A systematic review with meta-analysis of randomised, sham controlled trials.

Author information

1
Samueli Institute, Alexandria, Virginia, USA.
2
Department of Pain and Translational Symptom Science, School of Nursing, University of Maryland, Baltimore, Maryland, USA Department of Anesthesiology, School of Medicine, University of Maryland, Baltimore, Maryland, USA.
3
Program in Placebo Studies, Beth Israel Deaconess Medical Center, Harvard Medical School Boston, Massachusetts, USA.
4
The Methodist Hospital, Houston, Texas, USA.
5
Department of Bioethics, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
6
Department of Medical Psychology, University Medical Center Hamburg-Eppendorf, Hamburg-Eppendorf, Hamburg, Germany.
7
Institute of General Practice, Technische Universitat Munchen, Munich, Germany.
8
Institute of Medical Psychology, Ludwig-Maximilians-University Munich, Munich, Germany.

Abstract

OBJECTIVES:

To assess the quantity and quality of randomised, sham-controlled studies of surgery and invasive procedures and estimate the treatment-specific and non-specific effects of those procedures.

DESIGN:

Systematic review and meta-analysis.

DATA SOURCES:

We searched PubMed, EMBASE, CINAHL, CENTRAL (Cochrane Library), PILOTS, PsycInfo, DoD Biomedical Research, clinicaltrials.gov, NLM catalog and NIH Grantee Publications Database from their inception through January 2015.

STUDY SELECTION:

We included randomised controlled trials of surgery and invasive procedures that penetrated the skin or an orifice and had a parallel sham procedure for comparison.

DATA EXTRACTION AND ANALYSIS:

Three authors independently extracted data and assessed risk of bias. Studies reporting continuous outcomes were pooled and the standardised mean difference (SMD) with 95% CIs was calculated using a random effects model for difference between true and sham groups.

RESULTS:

55 studies (3574 patients) were identified meeting inclusion criteria; 39 provided sufficient data for inclusion in the main analysis (2902 patients). The overall SMD of the continuous primary outcome between treatment/sham-control groups was 0.34 (95% CI 0.20 to 0.49; p<0.00001; I(2)=67%). The SMD for surgery versus sham surgery was non-significant for pain-related conditions (n=15, SMD=0.13, p=0.08), marginally significant for studies on weight loss (n=10, SMD=0.52, p=0.05) and significant for gastroesophageal reflux disorder (GERD) studies (n=5, SMD=0.65, p<0.001) and for other conditions (n=8, SMD=0.44, p=0.004). Mean improvement in sham groups relative to active treatment was larger in pain-related conditions (78%) and obesity (71%) than in GERD (57%) and other conditions (57%), and was smaller in classical-surgery trials (21%) than in endoscopic trials (73%) and those using percutaneous procedures (64%).

CONCLUSIONS:

The non-specific effects of surgery and other invasive procedures are generally large. Particularly in the field of pain-related conditions, more evidence from randomised placebo-controlled trials is needed to avoid continuation of ineffective treatments.

KEYWORDS:

COMPLEMENTARY MEDICINE; INTERNAL MEDICINE; SURGERY

PMID:
26656986
PMCID:
PMC4679929
DOI:
10.1136/bmjopen-2015-009655
[Indexed for MEDLINE]
Free PMC Article

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