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Imperfect placebos are common in low back pain trials: a systematic review of the literature.

ABSTRACT: The placebo is an important tool to blind patients to treatment allocation and therefore minimise some sources of bias in clinical trials. However, placebos that are improperly designed or implemented may introduce bias into trials. The purpose of this systematic review was to evaluate the adequacy of placebo interventions used in low back pain trials. Electronic databases were searched systematically for randomised placebo-controlled trials of conservative interventions for low back pain. Trial selection and data extraction were performed by two reviewers independently. A total of 126 trials using over 25 different placebo interventions were included. The strategy most commonly used to enhance blinding was the provision of structurally equivalent placebos. Adequacy of blinding was assessed in only 13% of trials. In 20% of trials the placebo intervention was a potentially genuine treatment. Most trials that assessed patients' expectations showed that the placebo generated lower expectations than the experimental intervention. Taken together, these results demonstrate that imperfect placebos are common in low back pain trials; a result suggesting that many trials provide potentially biased estimates of treatment efficacy. This finding has implications for the interpretation of published trials and the design of future trials. Implementation of strategies to facilitate blinding and balance expectations in randomised groups need a higher priority in low back pain research.

SUBMITTER: Machado LA

PROVIDER: S-EPMC2443262 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature

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Imperfect placebos are common in low back pain trials: a systematic review of the literature.

Machado L A C LA Kamper S J SJ Herbert R D RD Maher C G CG McAuley J H JH

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society 20080418 7

The placebo is an important tool to blind patients to treatment allocation and therefore minimise some sources of bias in clinical trials. However, placebos that are improperly designed or implemented may introduce bias into trials. The purpose of this systematic review was to evaluate the adequacy of placebo interventions used in low back pain trials. Electronic databases were searched systematically for randomised placebo-controlled trials of conservative interventions for low back pain. Trial ...[more]

PMID: 18421484

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Project description:BackgroundMost patients in the secondary care sector consulting for low back pain (LBP) seem to have a more or less constant course of pain during the ensuing year. Fewer patients with LBP in the primary care sector report continual pain over a one-year period. However, not much is known about the long-term course of LBP in the general population. A systematic critical literature review was undertaken in order to study the natural course of LBP over time in the general population.MethodsA search of articles was performed in Pubmed, Cinahl and Psychinfo using the search terms 'epidemiology'; 'low back pain' or 'back pain'; 'prospective study' or 'longitudinal study'; 'follow-up', 'natural course', 'course' or 'natural history'; 'general population' or 'working population'. Inclusion criteria were that one of the objectives was to study the course of (L)BP in the adult population, that the period of follow-up was at least 3 months, and that there were three points of observation or more. The review was undertaken by two independent reviewers using three checklists relating to description of studies, quality and outcomes. The course of LBP was established in relation to those who, at baseline, were reported not to have LBP or to have LBP. Would this course be stable, fluctuating, worsening, or improving over time? A synthesis of results in relation to common patterns was presented in a table and interpreted in a narrative form.ResultsEight articles were included. Articles were different on time span, the number of surveys, and the definition of LBP. In six of the seven relevant studies, for those with no LBP at baseline, relatively substantial stable subgroups of people who continued to be LBP free were identified. In six of the seven relevant studies, definite stable subgroups of continued LBP were noted and improvement (becoming pain free) was never reported to be a common finding.ConclusionThe status of LBP in individuals of the general population appears to be relatively stable over time, perhaps particularly so for those without LBP at baseline.

Project description:Background and objectiveThe current treatments of primary musculoskeletal low back pain (LBP) have a low to moderate efficacy, which might be improved by looking at the contribution of placebo effects. However, the size of true placebo effects in LBP is unknown. Therefore, a systematic review and meta-analysis were executed of randomized controlled trials investigating placebo effects in LBP.Databases and data treatmentThe study protocol was registered in the international prospective register of systematic reviews Prospero (CRD42019148745). A literature search (in PubMed, Embase, The Cochrane Library, CINAHL and PsycINFO) up to 2021 February 16th yielded 2,423 studies. Two independent reviewers assessed eligibility and risk of bias.ResultsEighteen studies were eligible for the systematic review and 5 for the meta-analysis. Fourteen of the 18 studies were clinical treatment studies, and 4 were experimental studies specifically assessing placebo effects. The clinical treatment studies provided varying evidence for placebo effects in chronic LBP but insufficient evidence for acute and subacute LBP. Most experimental studies investigating chronic LBP revealed significant placebo effects. The meta-analysis of 5 treatment studies investigating chronic LBP depicted a significant moderate effect size of placebo for pain intensity (SMD = 0.57) and disability (SMD = 0.52).ConclusionsThis review shows a significant contribution of placebo effects to chronic LBP symptom relief in clinical and experimental conditions. The meta-analysis revealed that placebo effects can influence chronic LBP intensity and disability. However, additional studies are required for more supporting evidence and evidence for placebo effects in acute or subacute LBP.SignificanceThis systematic review and meta-analysis provides evidence of true placebo effects in low back pain (LBP). It shows a significant contribution of placebo effects to chronic LBP symptom relief. The results highlight the importance of patient- and context-related factors in fostering treatment effects in this patient group. New studies could provide insight into the potential value of actively making use of placebo effects in clinical practice.

Project description:Osteopathic manipulative treatment (OMT) is a distinctive modality commonly used by osteopathic physicians to complement their conventional treatment of musculoskeletal disorders. Previous reviews and meta-analyses of spinal manipulation for low back pain have not specifically addressed OMT and generally have focused on spinal manipulation as an alternative to conventional treatment. The purpose of this study was to assess the efficacy of OMT as a complementary treatment for low back pain.Computerized bibliographic searches of MEDLINE, EMBASE, MANTIS, OSTMED, and the Cochrane Central Register of Controlled Trials were supplemented with additional database and manual searches of the literature. Six trials, involving eight OMT vs control treatment comparisons, were included because they were randomized controlled trials of OMT that involved blinded assessment of low back pain in ambulatory settings. Data on trial methodology, OMT and control treatments, and low back pain outcomes were abstracted by two independent reviewers. Effect sizes were computed using Cohen's d statistic and meta-analysis results were weighted by the inverse variance of individual comparisons. In addition to the overall meta-analysis, stratified meta-analyses were performed according to control treatment, country where the trial was conducted, and duration of follow-up. Sensitivity analyses were performed for both the overall and stratified meta-analyses.Overall, OMT significantly reduced low back pain (effect size, -0.30; 95% confidence interval, -0.47 - -0.13; P = .001). Stratified analyses demonstrated significant pain reductions in trials of OMT vs active treatment or placebo control and OMT vs no treatment control. There were significant pain reductions with OMT regardless of whether trials were performed in the United Kingdom or the United States. Significant pain reductions were also observed during short-, intermediate-, and long-term follow-up.OMT significantly reduces low back pain. The level of pain reduction is greater than expected from placebo effects alone and persists for at least three months. Additional research is warranted to elucidate mechanistically how OMT exerts its effects, to determine if OMT benefits are long lasting, and to assess the cost-effectiveness of OMT as a complementary treatment for low back pain.

Project description:ObjectiveTo determine the proportion of chronic low back pain patients who achieve a clinically meaningful response from different pharmacologic and nonpharmacologic treatments.Data sourcesMEDLINE, EMBASE, Cochrane Library, and gray literature search.Study selectionPublished randomized controlled trials (RCTs) that reported a responder analysis of adults with chronic low back pain treated with any of the following 15 interventions: oral or topical nonsteroidal anti-inflammatory drugs (NSAIDs), exercise, acupuncture, spinal manipulation therapy, corticosteroid injections, acetaminophen, oral opioids, anticonvulsants, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors (SNRIs), selective serotonin reuptake inhibitors, cannabinoids, oral muscle relaxants, or topical rubefacients.SynthesisA total of 63 RCTs were included. There was moderate certainty that exercise (risk ratio [RR] of 1.71; 95% CI 1.37 to 2.15; number needed to treat [NNT] of 7), oral NSAIDs (RR = 1.44; 95% CI 1.17 to 1.78; NNT = 6), and SNRIs (duloxetine; RR = 1.25; 95% CI 1.13 to 1.38; NNT = 10) provide clinically meaningful benefits to patients with chronic low back pain. Exercise was the only intervention with sustained benefit (up to 48 weeks). There was low certainty that spinal manipulation therapy and topical rubefacients benefit patients. The benefit of acupuncture disappeared in higher-quality, longer (> 4 weeks) trials. Very low-quality evidence demonstrated that corticosteroid injections are ineffective. Patients treated with opioids had a greater likelihood of discontinuing treatment owing to an adverse event (number needed to harm of 5) than continuing treatment to derive any clinically meaningful benefit (NNT = 16), while those treated with SNRIs (duloxetine) had a similar likelihood of continuing treatment to attain benefit (NNT = 10) as those discontinuing the medication owing to an adverse event (number need to harm of 11). One trial each of anticonvulsants and topical NSAIDs found similar benefit to that of placebo. No RCTs of acetaminophen, cannabinoids, muscle relaxants, selective serotonin reuptake inhibitors, or tricyclic antidepressants met the inclusion criteria.ConclusionExercise, oral NSAIDs, and SNRIs (duloxetine) provide a clinically meaningful reduction in pain, with exercise being the only intervention that demonstrated sustained benefit after the intervention ended. Future high-quality trials that report responder analyses are required to provide a better understanding of the benefits and harms of interventions for patients with chronic low back pain.

Project description:BackgroundProprioceptive training (PrT) is popularly applied as preventive or rehabilitative exercise method in various sports and rehabilitation settings. Its effect on pain and function is only poorly evaluated. The aim of this systematic review was to summarise and analyse the existing data on the effects of PrT on pain alleviation and functional restoration in patients with chronic (? 3 months) neck- or back pain.MethodsRelevant electronic databases were searched from their respective inception to February 2014. Randomised controlled trials comparing PrT with conventional therapies or inactive controls in patients with neck- or low back pain were included. Two review authors independently screened articles and assessed risk of bias (RoB). Data extraction was performed by the first author and crosschecked by a second author. Quality of findings was assessed and rated according to GRADE guidelines. Pain and functional status outcomes were extracted and synthesised qualitatively and quantitatively.ResultsIn total, 18 studies involving 1380 subjects described interventions related to PrT (years 1994-2013). 6 studies focussed on neck-, 12 on low back pain. Three main directions of PrT were identified: Discriminatory perceptive exercises with somatosensory stimuli to the back (pPrT, n=2), multimodal exercises on labile surfaces (mPrT, n=13), or joint repositioning exercise with head-eye coordination (rPrT, n=3). Comparators entailed usual care, home based training, educational therapy, strengthening, stretching and endurance training, or inactive controls. Quality of studies was low and RoB was deemed moderate to high with a high prevalence of unclear sequence generation and group allocation (>60%). Low quality evidence suggests PrT may be more effective than not intervening at all. Low quality evidence suggests that PrT is no more effective than conventional physiotherapy. Low quality evidence suggests PrT is inferior to educational and behavioural approaches.ConclusionsThere are few relevant good quality studies on proprioceptive exercises. A descriptive summary of the evidence suggests that there is no consistent benefit in adding PrT to neck- and low back pain rehabilitation and functional restoration.

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Imperfect placebos are common in low back pain trials: a systematic review of the literature.

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Imperfect placebos are common in low back pain trials: a systematic review of the literature.

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