Small study effects in meta-analyses of osteoarthritis trials: meta-epidemiological study

Hypnosis for pain management during labour and childbirth

BACKGROUND

This review is one in a series of Cochrane Reviews investigating pain management for childbirth. These reviews all contribute to an overview of systematic reviews of pain management for women in labour, and share a generic protocol. We examined the current evidence regarding the use of hypnosis for pain management during labour and childbirth. This review updates the findings regarding hypnosis from an earlier review of complementary and alternative therapies for pain management in labour into a stand-alone review.

OBJECTIVES

To examine the effectiveness and safety of hypnosis for pain management during labour and childbirth.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (11 January 2012) and the reference lists of primary studies and review articles.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing preparation for labour using hypnosis and/or use of hypnosis during labour, with or without concurrent use of pharmacological or non-pharmacological pain relief methods versus placebo, no treatment or any analgesic drug or technique.

DATA COLLECTION AND ANALYSIS

Two assessors independently extracted data and assessed trial quality. Where possible we contacted study authors seeking additional information about data and methodology.

MAIN RESULTS

We included seven trials randomising a total of 1213 women. All but one of the trials were at moderate to high risk of bias. Although six of the seven trials assessed antenatal hypnotherapy, there were considerable differences between these trials in timing and technique. One trial provided hypnotherapy during labour. No significant differences between women in the hypnosis group and those in the control group were found for the primary outcomes: use of pharmacological pain relief (average risk ratio (RR) 0.63, 95% confidence interval (CI) 0.39 to 1.01, six studies, 1032 women), spontaneous vaginal birth (average RR 1.35, 95% CI 0.93 to 1.96, four studies, 472 women) or satisfaction with pain relief (RR 1.06, 95% CI 0.94 to 1.20, one study, 264 women). There was significant statistical heterogeneity in the data for use of pharmacological pain relief and spontaneous vaginal birth. The primary outcome of sense of coping with labour was reported in two studies as showing no beneficial effect (no usable data available for this review).  For secondary outcomes, no significant differences were identified between women in the hypnosis group and women in the control group for most outcomes where data were available. For example, there was no significant difference for satisfaction with the childbirth experience (average RR 1.36, 95% CI 0.52 to 3.59, two studies, 370 women), admissions to the neonatal intensive care unit (average RR 0.58, 95% CI 0.12 to 2.89, two studies, 347 women) or breastfeeding at discharge from hospital (RR 1.00, 95% CI 0.97 to 1.03, one study, 304 women). There was some evidence of benefits for women in the hypnosis group compared with the control group for pain intensity, length of labour and maternal hospital stay, although these findings were based on single studies with small numbers of women. Pain intensity was found to be lower for women in the hypnosis group than those in the control group in one trial of 60 women (mean difference (MD) -0.70, 95% CI -1.03 to -0.37). The same study found that the average length of labour from 5 cm dilation to birth (minutes) was significantly shorter for women in the hypnosis group (mean difference -165.20, 95% CI -223.53 to -106.87, one study, 60 women). Another study found that a smaller proportion of women in the hypnosis group stayed in hospital for more than two days after the birth compared with women in the control group (RR 0.11, 95% CI 0.02 to 0.83, one study, 42 women).

AUTHORS' CONCLUSIONS

There are still only a small number of studies assessing the use of hypnosis for labour and childbirth. Although the intervention shows some promise, further research is needed before recommendations can be made regarding its clinical usefulness for pain management in maternity care.

Rethinking clinical trials of transcranial direct current stimulation: participant and assessor blinding is inadequate at intensities of 2mA

Background

Many double-blind clinical trials of transcranial direct current stimulation (tDCS) use stimulus intensities of 2 mA despite the fact that blinding has not been formally validated under these conditions. The aim of this study was to test the assumption that sham 2 mA tDCS achieves effective blinding.

Methods

A randomised double blind crossover trial. 100 tDCS-naïve healthy volunteers were incorrectly advised that they there were taking part in a trial of tDCS on word memory. Participants attended for two separate sessions. In each session, they completed a word memory task, then received active or sham tDCS (order randomised) at 2 mA stimulation intensity for 20 minutes and then repeated the word memory task. They then judged whether they believed they had received active stimulation and rated their confidence in that judgement. The blinded assessor noted when red marks were observed at the electrode sites post-stimulation.

Results

tDCS at 2 mA was not effectively blinded. That is, participants correctly judged the stimulation condition greater than would be expected to by chance at both the first session (kappa level of agreement (κ) 0.28, 95% confidence interval (CI) 0.09 to 0.47 p = 0.005) and the second session (κ = 0.77, 95%CI 0.64 to 0.90), p = <0.001) indicating inadequate participant blinding. Redness at the reference electrode site was noticeable following active stimulation more than sham stimulation (session one, κ = 0.512, 95%CI 0.363 to 0.66, p<0.001; session two, κ = 0.677, 95%CI 0.534 to 0.82) indicating inadequate assessor blinding.

Conclusions

Our results suggest that blinding in studies using tDCS at intensities of 2 mA is inadequate. Positive results from such studies should be interpreted with caution.

Quantitative sensory testing in painful osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

To systematically review the use of quantitative sensory testing (QST) in pain characterisation (phenotyping) in osteoarthritis (OA).

METHODS

Six bibliographic databases (Medline, Embase, Amed, Cinahl, PubMed, Web of Science) were searched to identify studies published before May 2011. Data were extracted based on the primary site of OA, QST modalities, outcome measures and test sites. Standardised mean difference (SMD) and 95% confidence intervals (CIs) were calculated if possible. Publication bias was determined using funnel plot and Egger's test. Heterogeneity was examined using Cochran Q test and I2 statistic. Random effects model was used to pool the results.

RESULTS

Of 41 studies (2281 participants) included, 23 were case control studies, 15 case only studies, two randomised controlled trials, and one uncontrolled trial. The majority of studies examined pressure pain with smaller numbers using electrical and/or thermal stimuli. QST was more often applied to the affected joint than distal and remote sites. Of 20 studies comparing people with OA and healthy controls, seven provided sufficient information for meta-analysis. Compared with controls, people with OA had lower pressure pain thresholds (PPTs) both at the affected joint (SMD = -1.24, 95% CI -1.54, -0.93) and at remote sites (SMD = -0.88, 95% CI -1.11, -0.65).

CONCLUSION

QST of PPTs demonstrated good ability to differentiate between people with OA and healthy controls. Lower PPTs in people with OA in affected sites may suggest peripheral, and in remote sites central, sensitisation. PPT measurement merits further evaluation as a tool for phenotyping OA pain.

Low-dose droperidol (≤1 mg or ≤15 μg kg-1) for the prevention of postoperative nausea and vomiting in adults: quantitative systematic review of randomised controlled trials

CONTEXT

Droperidol is widely used for the prevention of postoperative nausea and vomiting (PONV) in European countries. It is unclear how efficacious low-dose droperidol is in the prevention of PONV.

OBJECTIVES

To test the efficacy of low-dose droperidol in the prevention of PONV in adults and to test for dose-responsiveness.

DESIGN

Systematic review of randomised controlled trials with meta-analyses.

DATA SOURCES

Comprehensive search in electronic databases (Medline, Embase, Central) up to June 2011. Additional trials were obtained from bibliographies of retrieved reports. No language restriction was applied.

ELIGIBILITY CRITERIA

Randomised trials testing prophylactic intravenous droperidol ≤1 mg or ≤15 μg kg compared with placebo (or no treatment) in adults undergoing general anaesthesia and reporting on PONV.

RESULTS

We analysed 25 trials (2957 patients). Doses varied from 0.25 to 1.0 mg. For prevention of early nausea (within 6 h postoperatively), relative risk (RR) was 0.45 (95% CI, 0.35 to 0.58); number needed to treat (NNT) was 7, 4, and 2 for low, medium and high baseline risk (i.e. control event rate 25, 50, 75%). For prevention of early vomiting, RR was 0.65 (95% CI, 0.57 to 0.74), NNT 11, 6, and 4. For prevention of late nausea (within 24 h), RR was 0.74 (95% CI, 0.62 to 0.87), NNT 15, 8, and 5. For prevention of late vomiting, RR was 0.61 (95% CI, 0.47 to 0.80), NNT 10, 5, and 3. Droperidol decreased the risk of headache but increased the risk of restlessness. For these outcomes there was no evidence of dose-responsiveness. There were no differences in the incidences of sedation or dizziness. Two patients receiving droperidol 0.625 mg had extrapyramidal symptoms. Cardiac toxicity data were not reported.

CONCLUSION

Prophylactic doses of droperidol of 1 mg or below are antiemetic. Because adverse drug reactions are likely to be dose-dependent, there is an argument to stop using doses of more than 1 mg.

Topical capsaicin (low concentration) for chronic neuropathic pain in adults

BACKGROUND

Topical creams with capsaicin are used to treat pain from a wide range of chronic conditions including neuropathic pain. Following application to the skin capsaicin causes enhanced sensitivity to noxious stimuli, followed by a period with reduced sensitivity and, after repeated applications, persistent desensitisation. There is uncertainty about the efficacy and tolerability of capsaicin for treating painful chronic neuropathies. This is an update of an earlier review of topical capsaicin for chronic neuropathic pain in adults that looked at all doses and formulations of capsaicin. The original review has now been split: here we consider only formulations using a low concentration of capsaicin (< 1%) applied several times daily over several weeks, while another review will consider a single application of capsaicin at a high concentration.

OBJECTIVES

To review the evidence from controlled trials on the efficacy and tolerability of topically applied low-concentration (< 1%) capsaicin in chronic neuropathic pain in adults.

SEARCH METHODS

Cochrane CENTRAL, MEDLINE, EMBASE and Oxford Pain Relief Database, searched to July 2012.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled studies of at least six weeks' duration, using low-concentration (< 1%) topical capsaicin to treat neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study quality and validity, and extracted data. Information was extracted on numbers of participants with pain relief (clinical improvement) after at least six weeks, and with local skin reactions, and used to calculate relative risk (or risk ratio, RR) and numbers needed to treat to benefit (NNT) and harm (NNH). Details of definition of pain relief and specific adverse events were sought.

MAIN RESULTS

No additional studies were identified for this update of low concentration capsaicin. Included studies were published before 1996. Six studies (389 participants in total) compared regular application of low dose (0.075%) capsaicin cream with placebo cream. There was substantial heterogeneity in results, probably as a result of the small number of studies each with small numbers of participants, as well as the different pain conditions studied and different definitions of "clinical success" reported. Only two studies reported data for the preferred primary outcome of at least 50% pain relief, and there were too few data for pooled analysis. Local skin reactions were more common with capsaicin, usually tolerable, and attenuated with time; the NNH for repeated low-dose application was 2.5 (95% confidence interval (CI) 2.1 to 3.1). All studies satisfied minimum criteria for quality and validity, but maintenance of blinding remains a potential problem.

AUTHORS' CONCLUSIONS

There were insufficient data to draw any conclusions about the efficacy of low-concentration capsaicin cream in the treatment of neuropathic pain. The information we have suggests that low-concentration topical capsaicin is without meaningful effect beyond that found in placebo creams; given the potential for bias from small study size, this makes it unlikely that low-concentration topical capsaicin has any meaningful use in clinical practice. Local skin irritation, which was often mild and transient but may lead to withdrawal, was common. Systemic adverse effects were rare.

Combination pharmacotherapy for the treatment of neuropathic pain in adults

BACKGROUND

Pharmacotherapy remains an important modality for the treatment of neuropathic pain. However, as monotherapy current drugs are associated with limited efficacy and dose-related side effects. Combining two or more different drugs may improve analgesic efficacy and, in some situations, reduce overall side effects (e.g. if synergistic interactions allow for dose reductions of combined drugs).

OBJECTIVES

This review evaluated the efficacy, tolerability and safety of various drug combinations for the treatment of neuropathic pain.

SEARCH METHODS

We identified randomised controlled trials (RCTs) of various drug combinations for neuropathic pain from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 9 April 2012.

SELECTION CRITERIA

Double-blind, randomised studies comparing combinations of two or more drugs (systemic or topical) to placebo and/or at least one other comparator for the treatment of neuropathic pain.

DATA COLLECTION AND ANALYSIS

Data extracted from each study included: proportion of participants a) reporting ≥ 30% pain reduction from baseline OR ≥ moderate pain relief OR ≥ moderate global improvement; b) dropping out of the trial due to treatment-emergent adverse effects; c) reporting each specific adverse effect (e.g. sedation, dizziness) of ≥ moderate severity. The primary comparison of interest was between study drug(s) and one or both single-agent comparators. We combined studies if they evaluated the same drug class combination at roughly similar doses and durations of treatment. We used RevMan 5 to analyse data for binary outcomes.

MAIN RESULTS

We identified 21 eligible studies: four (578 participants) evaluated the combination of an opioid with gabapentin or pregabalin; two (77 participants) evaluated an opioid with a tricyclic antidepressant; one (56 participants) of gabapentin and nortriptyline; one (120 participants) of gabapentin and alpha-lipoic acid, three (90 participants) of fluphenazine with a tricyclic antidepressant; three (90 participants) of an N-methyl-D-aspartate (NMDA) blocker with an agent from a different drug class; five (604 participants) of various topical medications; one (313 participants) of tramadol with acetaminophen; and another one (44 participants) of a cholecystokinin blocker (L-365,260) with morphine. The majority of combinations evaluated to date involve drugs, each of which share some element of central nervous system (CNS) depression (e.g. sedation, cognitive dysfunction). This aspect of side effect overlap between the combined agents was often reflected in similar or higher dropout rates for the combination and may thus substantially limit the utility of such drug combinations. Meta-analysis was possible for only one comparison of only one combination, i.e. gabapentin + opioid versus gabapentin alone. This meta-analysis involving 386 participants from two studies demonstrated modest, yet statistically significant, superiority of a gabapentin + opioid combination over gabapentin alone. However, this combination also produced significantly more frequent side effect-related trial dropouts compared to gabapentin alone.

AUTHORS' CONCLUSIONS

Multiple, good-quality studies demonstrate superior efficacy of two-drug combinations. However, the number of available studies for any one specific combination, as well as other study factors (e.g. limited trial size and duration), preclude the recommendation of any one specific drug combination for neuropathic pain. Demonstration of combination benefits by several studies together with reports of widespread clinical polypharmacy for neuropathic pain surely provide a rationale for additional future rigorous evaluations. In order to properly identify specific drug combinations which provide superior efficacy and/or safety, we recommend that future neuropathic pain studies of two-drug combinations include comparisons with placebo and both single-agent components. Given the apparent adverse impact of combining agents with similar adverse effect profiles (e.g. CNS depression), the anticipated development and availability of non-sedating neuropathic pain agents could lead to the identification of more favourable analgesic drug combinations in which side effects are not compounded.

Caffeine as an analgesic adjuvant for acute pain in adults

BACKGROUND

Caffeine has been added to common analgesics such as paracetamol, ibuprofen, and aspirin, in the belief that it enhances analgesic efficacy. Evidence to support this belief is limited and often based on invalid comparisons.

OBJECTIVES

To assess the relative efficacy in acute pain of a single dose of any analgesic plus caffeine against the same dose of analgesic alone.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, and the Oxford Pain Relief Database to January 2012, and also carried out Internet searches and contacted pharmaceutical companies known to have carried out trials that have not been published.

SELECTION CRITERIA

We included randomised, double-blind studies that compared a single dose of analgesic plus caffeine with the same dose of the analgesic alone in the treatment of acute pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility and quality of studies, and extracted data. Any disagreements or uncertainties were settled by discussion with a third review author. We sought any validated measure of analgesic efficacy, but particularly the number of participants experiencing at least 50% of the maximum possible pain relief over four to six hours, participants reporting a global evaluation of treatment of very good or excellent, or headache relief after two hours. We pooled comparable data to look for a statistically significant difference, and calculated numbers needed to treat to benefit (NNT) with caffeine. We also looked for any numerical superiority associated with the addition of caffeine, and information about any serious adverse events.

MAIN RESULTS

We identified 19 studies (7238 participants) in valid comparisons. Most studies used paracetamol or ibuprofen, with 100 mg to 130 mg caffeine, and the most common pain conditions studied were postoperative dental pain, postpartum pain, and headache. There was a small but statistically significant benefit with caffeine used at doses of 100 mg or more, which was not dependent on the pain condition or type of analgesic. About 5% to 10% more participants achieve a good level of pain relief (at least 50% of the maximum) with the addition of caffeine, giving a NNT of about 15.Most comparisons individually demonstrated numerical superiority with caffeine, but not statistical superiority. One serious adverse event was reported with caffeine, but was considered unrelated to any study medication.We know or suspect of the existence of 20 additional studies with 9785 participants for which data for analysis were not obtainable. The additional analgesic effect of caffeine remained statistically significant but clinically less important even if all the known missing data had no effect; that is not likely to be the case.

AUTHORS' CONCLUSIONS

The addition of caffeine (≥ 100 mg) to a standard dose of commonly used analgesics provides a small but important increase in the proportion of participants who experience a good level of pain relief.

Milnacipran for neuropathic pain and fibromyalgia in adults

BACKGROUND

Milnacipran is a serotonin-norepinephrine reuptake inhibitor (SNRI) that is sometimes used to treat chronic neuropathic pain and fibromyalgia.

OBJECTIVES

To evaluate the analgesic efficacy and adverse effects of milnacipran in the management of chronic neuropathic pain or fibromyalgia.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and EMBASE to 4th of January 2012, together with reference lists of retrieved papers and reviews.

SELECTION CRITERIA

We included randomised, double-blind studies of eight weeks duration or longer, comparing milnacipran with placebo or another active treatment in chronic neuropathic pain or fibromyalgia.

DATA COLLECTION AND ANALYSIS

We extracted efficacy and adverse event data, and two study authors examined issues of study quality independently.

MAIN RESULTS

Five studies (4138 participants) were included, all of which were placebo-controlled, involved participants with fibromyalgia, and used titration to a target dose of 100 mg or 200 mg milnacipran. There were no other active comparators or studies in other neuropathic pain conditions. Study quality was generally good, although the imputation method used in analyses of the primary outcomes could overestimate treatment effect.Both doses of milnacipran provided moderate levels of pain relief to about 40% of those treated, compared to 30% with placebo, giving a number needed to treat of 8 to 10. Adverse events were common in both milnacipran (87%) and placebo (78%) groups, but serious adverse events (< 2%) did not differ between groups. Nausea and constipation were the most common events showing the greatest difference between groups (number needed to treat for an additional harmful outcome of 7 and 13 respectively, compared with placebo).Withdrawals for any reason were more common with milnacipran than placebo, and more common with 200 mg than 100 mg (NNH of 23 and 8.8 respectively, compared with placebo). This was largely driven by adverse event withdrawals, where the NNH compared with placebo was 14 for 100 mg, and 7.0 for 200 mg). Withdrawals due to lack of efficacy were more common with milnacipran than placebo but did not differ between doses (number needed to treat to prevent an additional unwanted outcome of 45 and 41 respectively).

AUTHORS' CONCLUSIONS

The evidence available indicates that milnacipran 100 mg or 200 mg is effective for a minority in the treatment of pain due to fibromyalgia, providing moderate levels of pain relief (at least 30%) to about 40% of participants, compared with about 30% with placebo. There were insufficient data to assess substantial levels of pain relief (at least 50%), and the use of last observation carried forward imputation may overestimate drug efficacy. Milnacipran is associated with increased adverse events and adverse event withdrawals, which were significantly greater for the higher dose. There were no data for the use of milnacipran for other chronic neuropathic pain conditions.

A generalized weighting regression-derived meta-analysis estimator robust to small-study effects and heterogeneity

Heterogeneity and small-study effects are major concerns for the validity of meta-analysis. Although random effects meta-analysis provides a partial solution to heterogeneity, neither takes into account the presence of small-study effects, although they can rarely be ruled out with certainty. In this paper, we facilitate a better understanding of the properties of a recently described regression-based approach to deriving a meta-analysis estimator robust to small-study effects and unexplainable heterogeneity. The weightings of studies in the meta-analysis are derived algebraically for the regression model and compared with the weightings allocated to studies by fixed and random effects models. These weightings are compared in case studies with and without small-study effects. The presence of small-study effects causes pooled estimates from fixed and random effects meta-analyses to differ, potentially markedly, as a result of the different weights allocated to individual studies. Because random effects meta-analysis gives more weight to smaller studies, it becomes more vulnerable to the small-study effects. The regression approach gives heavier weight to the larger studies than either the fixed or random effects models, leading to its dominance in the estimated pooled effect. The weighting properties of the proposed regression-derived meta-analysis estimator are presented and compared with those of the standard meta-analytic estimators. We propose that there is much to recommend the routine use of this model as a reliable way to derive a pooled meta-analysis estimate that is robust to potential small-study effects, while still accommodating heterogeneity, even though uncertainty will often be considerably larger than for standard estimators.

Impact of single centre status on estimates of intervention effects in trials with continuous outcomes: meta-epidemiological study

OBJECTIVE

To compare estimates of intervention effects between single centre and multicentre randomised controlled trials with continuous outcomes.

DESIGN

Meta-epidemiological study.

DATA SOURCES

26 meta-analyses totalling 292 randomised controlled trials (177 single centre, 115 multicentre) with continuous outcomes published between January 2007 and January 2010 in the Cochrane database of systematic reviews.

DATA EXTRACTION

Data were extracted on characteristics of trials, single or multicentre status, risk of bias using the risk of bias tool of the Cochrane Collaboration, and results.

DATA SYNTHESIS

The intervention effects were estimated with standardised mean differences. For each meta-analysis, random effects meta-regression was used to estimate the difference in standardised mean differences between single centre and multicentre trials. Differences in standardised mean differences were then pooled across meta-analyses by a random-effects meta-analysis model. A combined difference in standardised mean differences of less than 0 indicated that single centre trials showed larger treatment effects, on average, than did multicentre trials. Because single centre trials may be more prone to publication bias and may have lower methodological quality than multicentre trials, sensitivity analyses were done with adjustment for sample size and domains of the risk of bias tool.

RESULTS

Single centre trials showed larger intervention effects than did multicentre trials (combined difference in standardised mean differences -0.09, 95% confidence interval -0.17 to -0.01, P=0.04), with low heterogeneity across individual meta-analyses (I(2)=0%, between meta-analyses variance τ(2)=0.00). Adjustment for sample size slightly attenuated the difference (-0.08, -0.17 to 0.01). Adjustment for risk of bias yielded similar estimates with wider confidence intervals, some of them crossing 0 (-0.09, -0.17 to 0.00 for overall risk of bias).

CONCLUSIONS

On average, single centre clinical trials with continuous outcomes showed slightly larger intervention effects than did multicentre trials. Further research is needed to investigate potential causes of these differences.

Placebo effect was influenced by publication year in three-armed acupuncture trials

OBJECTIVES

We investigated the relationship between the placebo effect and the trial or patient characteristics.

DATA SOURCES

We identified randomized clinical trials with acupuncture, sham and no-treatment groups in which no-treatment or conventional therapy was applied to the no-treatment group. Thirty-one trials in which no treatment was applied in the no-treatment group were categorised as 'strict' trials. Thirty-nine trials in which no-treatment or conventional therapy was applied to the no-treatment group were categorised as 'less strict' trials. We calculated the treatment effect, defined as the difference in the effect size between the acupuncture and no-treatment groups, and the placebo effect, defined as the difference in the effect size between the sham and no-treatment groups. Then, a random effect meta-regression analysis was performed on the two effects with respect to trial or patient characteristics.

RESULTS

The treatment effect was not found to be associated with any factors in both the strict and less strict trials. However, the placebo effect was found to be associated with the publication year in both the strict and less strict trials (P=0.009 and 0.005, respectively). The placebo effect increased by 0.05 in effect size per year in trials that were published more recently.

CONCLUSION

While the treatment effect was not influenced by any trial or patient characteristics, the placebo effect was associated with the publication year.

Serum cartilage oligomeric matrix protein (sCOMP) is elevated in patients with knee osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

To be used in diagnostic studies, it must be demonstrated that biomarkers can differentiate between diseased and non-diseased patients. Therefore, the purpose of this study was to answer the following questions: (1) Is serum cartilage oligomeric matrix protein (sCOMP) elevated in patients with radiographically diagnosed knee osteoarthritis (OA) compared to controls? (2) Are there differences in sCOMP levels when comparing differing radiographic OA severities to controls?

METHODS

Systematic review and meta-analysis.

DATA SOURCES

A systematic search of CINAHL, PEDro, Medline, and SportsDiscus was completed in March 2010.

KEYWORDS

knee, osteoarthritis, sCOMP, radiography. Study inclusion criteria: Studies were written in English, compared healthy adults with knee OA patients, used the Kellgren Lawrence (K/L) classification, measured sCOMP, and reported means and standard deviations for sCOMP.

RESULTS

For question 1, seven studies were included resulting in seven comparisons. A moderate overall effect size (ES) indicated sCOMP was consistently elevated in those with radiographically diagnosed knee OA when compared to controls (ES = 0.60, P < 0.001). For question 2, four studies were included resulting in 13 comparisons between radiographic OA severity levels and controls. Strong ESs were calculated for K/L-1 (ES = 1.43, P = 0.28), K/L-3 (ES = 1.05, P = 0.04), and K/L-4 (ES = 1.40, P = 0.003). A moderate ES was calculated for K/L-2 (ES = 0.60, P = 0.01).

CONCLUSIONS

These results indicate sCOMP is elevated in patients with knee OA and is sensitive to OA disease progression. Future research studies with a higher level of evidence should be conducted to investigate the use of this biomarker as an indicator for OA development and progression.

Can research assessments themselves cause bias in behaviour change trials? A systematic review of evidence from solomon 4-group studies

Background

The possible effects of research assessments on participant behaviour have attracted research interest, especially in studies with behavioural interventions and/or outcomes. Assessments may introduce bias in randomised controlled trials by altering receptivity to intervention in experimental groups and differentially impacting on the behaviour of control groups. In a Solomon 4-group design, participants are randomly allocated to one of four arms: (1) assessed experimental group; (2) unassessed experimental group (3) assessed control group; or (4) unassessed control group. This design provides a test of the internal validity of effect sizes obtained in conventional two-group trials by controlling for the effects of baseline assessment, and assessing interactions between the intervention and baseline assessment. The aim of this systematic review is to evaluate evidence from Solomon 4-group studies with behavioural outcomes that baseline research assessments themselves can introduce bias into trials.

Methodology/Principal Findings

Electronic databases were searched, supplemented by citation searching. Studies were eligible if they reported appropriately analysed results in peer-reviewed journals and used Solomon 4-group designs in non-laboratory settings with behavioural outcome measures and sample sizes of 20 per group or greater. Ten studies from a range of applied areas were included. There was inconsistent evidence of main effects of assessment, sparse evidence of interactions with behavioural interventions, and a lack of convincing data in relation to the research question for this review.

Conclusions/Significance

There were too few high quality completed studies to infer conclusively that biases stemming from baseline research assessments do or do not exist. There is, therefore a need for new rigorous Solomon 4-group studies that are purposively designed to evaluate the potential for research assessments to cause bias in behaviour change trials.

Valproic acid and sodium valproate for neuropathic pain and fibromyalgia in adults

BACKGROUND

Valproic acid and its sodium salt (sodium valproate) are antiepileptic drugs that are sometimes used to treat chronic neuropathic pain and fibromyalgia, although they are not licensed for this use.

OBJECTIVES

To evaluate the analgesic efficacy and adverse effects of valproic acid and sodium valproate in the management of chronic neuropathic pain and fibromyalgia.

SEARCH STRATEGY

We identified randomised controlled trials (RCTs) of valproic acid and sodium valproate in acute, and chronic pain by searching MEDLINE, EMBASE and Cochrane CENTRAL to June 2011, together with reference lists of retrieved papers and reviews.

SELECTION CRITERIA

RCTs that were double blind and of eight-weeks duration or longer, reporting on analgesic effects and adverse events with valproic acid and sodium valproate in the treatment of chronic neuropathic pain and fibromyalgia.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted results and scored for quality. We extracted efficacy and adverse event data, and examined issues of study quality.

MAIN RESULTS

We included three studies, two in diabetic neuropathy (42 participants treated with valproate, 42 with placebo), and one in post-herpetic neuralgia (23 treated with divalproex sodium, 22 with placebo). Study duration was eight or 12 weeks. No studies were found in fibromyalgia.Only one study reported one of our primary outcomes (≥ 50% pain relief), while all three reported group means for pain reduction from baseline to endpoint. In all three studies; efficacy results were given only for participants who completed the study. One study in diabetic neuropathy and the study in post-herpetic neuralgia reported significant differences between active and placebo groups, but there were insufficient data for reliable pooled analysis.More adverse events were reported with active treatment than placebo, and included nausea, drowsiness and abnormal liver function tests. One participant taking sodium valproate withdrew due to serious derangement of liver enzymes.

AUTHORS' CONCLUSIONS

These three studies no more than hint that sodium valproate may reduce pain in diabetic neuropathy, and divalproex sodium in post-herpetic neuralgia, but the use of 'completer' analysis may overestimate efficacy, and there were too few data for pooled analysis of efficacy or harm, or to have confidence in the results of the individual studies. There is insufficient evidence to support the use of valproic acid or sodium valproate as a first-line treatment for neuropathic pain. There is more robust evidence of greater efficacy for a small number of other drugs.

Physiatric approaches to pain management in osteoarthritis: a review of the evidence of effectiveness

SUMMARY Osteoarthritis (OA), which is highly prevalent in the general population, is one of the leading causes of pain and physical disability. A large number of nonpharmacological interventions are available for the management of pain in patients with OA. These include education and self-management, weight reduction, various forms of exercises, physical agents/modalities, complementary therapies, manual therapy, unloading strategies such as braces and orthoses, and balneotherapy. The aim of this article is to assess the evidence of effectiveness of nonpharmacological interventions pertaining to physiatry to identify best practices for pain management in OA.

C-reactive protein as a predictor of mortality in critically ill patients: a meta-analysis and systematic review

C-reactive protein is a marker of inflammatory response and has been widely investigated in cardiovascular and infectious diseases, especially to monitor therapeutic success. However, its role as a predictor of clinical outcome in critically ill patients remains uncertain and controversial. The objective of this study was to investigate the predictive value of C-reactive protein in critically ill patients. The databases of PubMed, the Cochrane clinical trial database and EMBASE (from inception to August 2010) were searched. Prospective non-randomised clinical studies comparing C-reactive protein concentrations between survivors and non-survivors were included. Pooled mean difference in C-reactive protein concentrations between survivors and non-survivors was calculated. Heterogeneity was analysed by I2. Sensitivity and subgroup analyses were conducted to explore the heterogeneity. Fourteen studies containing a total of 1969 patients were finally included in our analysis. The weighted mean difference in the C-reactive protein levels between survivors and non-survivors was 9.15 mg/l (95% confidence interval -6.50 to 24.81). The heterogeneity was large with I2 = 92%. Subsequent investigation of the heterogeneity with sensitivity analyses yielded no significant differences. The subgroup analysis showed that the weighted mean difference in early (within 48 hours) C-reactive protein levels between survivors and non-survivors was not significantly different, in contrast to the late (beyond 48 hours) C-reactive protein level. This was significantly greater in non-survivors with a weighted mean difference of 63.80 mg/l (95% confidence interval 35.67 to 91.93). Our systematic review shows that while the early C-reactive protein concentration is not a good predictor of survival in critically ill patients, the late C-reactive protein concentration may help to identify patients who are at risk of death.

Hydroxyapatite (HA) coating appears to be of benefit for implant durability of tibial components in primary total knee arthroplasty

BACKGROUND

It is unclear whether there is a clinical benefit to adding hydroxyapatite (HA) coatings to total knee implants, especially with the tibial component, where failure of the implant more often occurs. A systematic review of the literature was undertaken to identify all prospective randomized trials for determining whether the overall clinical results (as a function of durability, function, and adverse events) favored HA-coated tibial components.

METHODS

A comprehensive literature search was performed for the years 1990 to September 16, 2010. We restricted our search to randomized controlled trials involving participants receiving either an HA-coated tibia or other forms of tibial fixation. The primary outcome measures evaluated were durability, function, and acute adverse events.

RESULTS

Data from 926 evaluable primary total knee implants in 14 studies were analyzed. Using an RSA definition for durability, HA-coated tibial components (porous or press-fit) without screw fixation were less likely to be unstable at 2 years than porous and cemented metal-backed tibial components (RR = 0.58, 95% CI: 0.34-0.98; p = 0.04, I(2) = 39%, M-H random effects model). There was no significant difference in durability, as measured from revision and evaluated at 2 and 8-10 years, between groups. Also, functional status using different validated measures showed no significant difference at 2 and 5 years, no matter what measure was used. Lastly, there was no significant difference in adverse events. Limitations included small numbers of evaluable patients (≤ 50) in 7 of the 14 trials identified, and a lack of "hard" evidence of durability with need for replacement (i.e. frank failure, pain, or loss of functionality).

INTERPRETATION

In patients > 65 years of age, an HA-coated tibial implant may provide better durability than other forms of tibial fixation. Larger trials should be undertaken comparing the long-term durability, function, and adverse events of HA-coated implants with those of other porous-coated tibial implants in younger, more active OA patients.

Systematic review and meta-analysis of the association between complement component 3 and age-related macular degeneration: a HuGE review and meta-analysis

The authors performed a meta-analysis to estimate the magnitude of polymorphism effects for the complement component C3 gene (C3) and their possible mode of action on age-related macular degeneration (AMD). The meta-analysis included 16 and 7 studies for rs2230199 and rs1047286, respectively. Data extraction and risk of bias assessments were performed in duplicate, and heterogeneity and publication bias were explored. There was moderate evidence for association between both polymorphisms and AMD in Caucasians. For rs2230199, patients with CG and GG genotypes were 1.44 (95% confidence interval (CI): 1.33, 1.56) and 1.88 (95% CI: 1.59, 2.23) times more likely to have AMD than patients with the CC genotype. For rs1047286, GA and AA genotypes had 1.27 (95% CI: 1.15, 1.41) and 1.70 (95% CI: 1.27, 2.11) times higher risk of AMD than did GG genotypes. These gene effects suggested an additive model. The population attributable risks for the GG/GC and AA/GA genotypes are approximately 5%-10%. Subgroup analysis by ethnicity indicates that these variants are very infrequent in Asians and that the observed gene effects are based largely on the high frequency within Caucasian populations. This meta-analysis supports the association between C3 and AMD and provides a robust estimate of the genetic risk.

Three-armed trials including placebo and no-treatment groups may be subject to publication bias: systematic review

Background

It has been argued that placebos may not have important clinical impacts in general. However, there is increasing evidence of a publication bias among trials published in journals. Therefore, we explored the potential for publication bias in randomized trials with active treatment, placebo, and no-treatment groups.

Methods

Three-armed randomized trials of acupuncture, acupoint stimulation, and transcutaneous electrical stimulation were obtained from electronic databases. Effect sizes between treatment and placebo groups were calculated for treatment effect, and effect sizes between placebo and no-treatment groups were calculated for placebo effect. All data were then analyzed for publication bias.

Results

For the treatment effect, small trials with fewer than 100 patients per arm showed more benefits than large trials with at least 100 patients per arm in acupuncture and acupoint stimulation. For the placebo effect, no differences were found between large and small trials. Further analyses showed that the treatment effect in acupuncture and acupoint stimulation may be subject to publication bias because study design and any known factors of heterogeneity were not associated with the small study effects. In the simulation, the magnitude of the placebo effect was smaller than that calculated after considering publication bias.

Conclusions

Randomized three-armed trials, which are necessary for estimating the placebo effect, may be subject to publication bias. If the magnitude of the placebo effect is assessed in an intervention, the potential for publication bias should be investigated using data related to the treatment effect.

Adjusting for publication biases across similar interventions performed well when compared with gold standard data

OBJECTIVE

To extend, apply, and evaluate a regression-based approach to adjusting meta-analysis for publication and related biases. The approach uses related meta-analyses to improve estimation by borrowing strength on the degree of bias.

STUDY DESIGN AND SETTING

The proposed adjustment approach is described. Adjustments are applied both independently and by borrowing strength across journal-extracted data on the effectiveness of 12 antidepressant drugs from placebo-controlled trials. The methods are also applied to Food and Drug Administration (FDA) data obtained on the same 12 drugs. Results are compared, viewing the FDA observed data as gold standard.

RESULTS

Estimates adjusted for publication biases made independently for each drug were very uncertain using both the journal and FDA data. Adjusted estimates were much more precise when borrowing strength across meta-analyses. Reassuringly, adjustments in this way made to the journal data agreed closely with the observed estimates from the FDA data, while the adjusted FDA results changed only minimally from those observed from the FDA data.

CONCLUSION

The method worked well in the case study considered and therefore further evaluation is encouraged. It is suggested that this approach may be especially useful when adjusting several meta-analyses on similar interventions and outcomes, particularly when there are small numbers of studies.

Osteoarthritis year 2010 in review: pharmacological therapies

This review highlights a selection of original studies related to the treatment of osteoarthritis in 2010.

Gabapentin for chronic neuropathic pain and fibromyalgia in adults

BACKGROUND

This review updates parts of two earlier Cochrane reviews investigating effects of gabapentin in chronic neuropathic pain (pain due to nerve damage). Antiepileptic drugs are used to manage pain, predominantly for chronic neuropathic pain, especially when the pain is lancinating or burning.

OBJECTIVES

To evaluate the analgesic effectiveness and adverse effects of gabapentin for chronic neuropathic pain management.

SEARCH STRATEGY

We identified randomised trials of gabapentin in acute, chronic or cancer pain from MEDLINE, EMBASE, and CENTRAL. We obtained clinical trial reports and synopses of published and unpublished studies from Internet sources. The date of the most recent search was January 2011.

SELECTION CRITERIA

Randomised, double-blind studies reporting the analgesic and adverse effects of gabapentin in neuropathic pain with assessment of pain intensity and/or pain relief, using validated scales. Participants were adults aged 18 and over.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. We calculated numbers needed to treat to benefit (NNTs), concentrating on IMMPACT (Initiative on Methods, Measurement and Pain Assessment in Clinical Trials) definitions of at least moderate and substantial benefit, and to harm (NNH) for adverse effects and withdrawal. Meta-analysis was undertaken using a fixed-effect model.

MAIN RESULTS

Twenty-nine studies (3571 participants), studied gabapentin at daily doses of 1200 mg or more in 12 chronic pain conditions; 78% of participants were in studies of postherpetic neuralgia, painful diabetic neuropathy or mixed neuropathic pain. Using the IMMPACT definition of at least moderate benefit, gabapentin was superior to placebo in 14 studies with 2831 participants, 43% improving with gabapentin and 26% with placebo; the NNT was 5.8 (4.8 to 7.2). Using the IMMPACT definition of substantial benefit, gabapentin was superior to placebo in 13 studies with 2627 participants, 31% improving with gabapentin and 17% with placebo; the NNT was 6.8 (5.6 to 8.7). These estimates of efficacy are more conservative than those reported in a previous review. Data from few studies and participants were available for other painful conditions.Adverse events occurred significantly more often with gabapentin. Persons taking gabapentin can expect to have at least one adverse event (66%), withdraw because of an adverse event (12%), suffer dizziness (21%), somnolence (16%), peripheral oedema (8%), and gait disturbance (9%). Serious adverse events (4%) were no more common than with placebo.There were insufficient data for comparisons with other active treatments.

AUTHORS' CONCLUSIONS

Gabapentin provides pain relief of a high level in about a third of people who take if for painful neuropathic pain. Adverse events are frequent, but mostly tolerable. More conservative estimates of efficacy resulted from using better definitions of efficacy outcome at higher, clinically important, levels, combined with a considerable increase in the numbers of studies and participants available for analysis.

Telephone-delivered cognitive behavioural therapy: a systematic review and meta-analysis

Telephone-delivered cognitive behavioural therapy (CBT) is an increasingly popular mode of delivering care. We conducted a systematic review which focused on physical health outcomes. Literature searches were conducted to identify randomized controlled trials (RCTs) comparing telephone-delivered CBT for improving physical health with any other therapy or routine care in patients with chronic illness. Eight RCTs (1093 patients) met the eligibility criteria and were included in the review. Six of the eight RCTs compared the telephone intervention with routine care, one trial employed symptom monitoring as the control condition and the final trial compared telephone CBT to telephone supportive emotion-focused therapy. Meta-analysis found that telephone-delivered CBT significantly improved physical health in people with chronic illness (d = 0.225, 95% CI = 0.105, 0.344). Moderator analyses found that less therapist contact was associated with better outcomes, and telephone-delivered CBT was more effective for chronic illnesses that are not immediately life-threatening. The results of the meta-analysis support the use of telephone-delivered CBT as a tool for improving health in people with chronic illness. There is a need for future trials to evaluate cost-effectiveness.

Adult consequences of late adolescent alcohol consumption: a systematic review of cohort studies

BACKGROUND

Although important to public policy, there have been no rigorous evidence syntheses of the long-term consequences of late adolescent drinking.

METHODS AND FINDINGS

This systematic review summarises evidence from general population cohort studies of drinking between 15-19 years old and any subsequent outcomes aged 20 or greater, with at least 3 years of follow-up study. Fifty-four studies were included, of which 35 were assessed to be vulnerable to bias and/or confounding. The principal findings are: (1) There is consistent evidence that higher alcohol consumption in late adolescence continues into adulthood and is also associated with alcohol problems including dependence; (2) Although a number of studies suggest links to adult physical and mental health and social consequences, existing evidence is of insufficient quality to warrant causal inferences at this stage.

CONCLUSIONS

There is an urgent need for high quality long-term prospective cohort studies in order to better understand the public health burden that is consequent on late adolescent drinking, both in relation to adult drinking and more broadly. Reducing drinking during late adolescence is likely to be important for preventing long-term adverse consequences as well as protecting against more immediate harms. Please see later in the article for the Editors' Summary.

Corticosteroid and antiviral therapy for Bell's palsy: a network meta-analysis

Background

Previous meta-analyses of treatments for Bell's palsy are still inconclusive due to different comparators, insufficient data, and lack of power. We therefore conducted a network meta-analysis combining direct and indirect comparisons for assessing efficacy of steroids and antiviral treatment (AVT) at 3 and 6 months.

Methods

We searched Medline and EMBASE until September 2010 using PubMed and Elsviere search engines. A network meta-analysis was performed to assess disease recovery using a mixed effects hierarchical model. Goodness of fit of the model was assessed, and the pooled odds ratio (OR) and 95% confidence interval (CI) were estimated.

Results

Six studies (total n = 1805)were eligible and contributed to the network meta-analysis. The pooled ORs for resolution at 3 months were 1.24 (95% CI: 0.79 - 1.94) for Acyclovir plus Prednisolone and 1.02 (95% CI: 0.73 - 1.42) for Valacyclovir plus Prednisolone, versus Prednisolone alone. Either Acyclovir or Valacyclovir singly had significantly lower efficacy than Prednisolone alone, i.e., ORs were 0·44 (95% CI: 0·28 - 0·68) and 0·60 (95% CI: 0·42 - 0·87), respectively. Neither of the antiviral agents was significantly different compared with placebo, with a pooled OR of 1·25 (95% CI: 0·78 - 1·98) for Acyclovir and 0·91 (95% CI: 0·63 - 1·31) for Valacyclovir. Overall, Prednisolone-based treatment increased the chance of recovery 2-fold (95% CI: 1·55 - 2·42) compared to non-Prednisolone-based treatment. To gain 1 extra recovery, 6 and 26 patients need to be treated with Acyclovir and prednisolone compared to placebo and prednisolone alone, respectively.

Conclusions

Our evidence suggests that the current practice of treating Bell's palsy with AVT plus corticosteroid may lead to slightly higher recovery rates compared to treating with prednisone alone but this does not quite reach statistical significance; prednisone remains the best evidence-based treatment.

The effectiveness of two-compound formulation calcipotriol and betamethasone dipropionate gel in the treatment of moderately severe scalp psoriasis: a systematic review of direct and indirect evidence

OBJECTIVES

To evaluate the two-compound formulation (TCF) calcipotriol and betamethasone dipropionate (BDP) gel versus other topical therapies for scalp psoriasis in adults using direct and indirect comparisons.

METHODS

A systematic review identified 10 randomised controlled trials (RCTs) of topical treatments used in clinical practice for moderately severe scalp psoriasis. A meta-analysis was undertaken to obtain estimates of clinical effectiveness using recommended efficacy and safety outcome measures. We determined the proportion of responding patients using two definitions: i) 'controlled disease' using the Investigator Global Assessment (IGA) rating scale and ii) a score of 0 or 1 on the Total Sign Score (TSS). Tolerability was extracted in terms of percentages of patients experiencing all adverse events (AEs), skin AEs and withdrawals due to AEs. Direct comparisons were performed where head-to-head data were available. For other comparators where TCF gel was compared indirectly, 'pairs' of trials were compared on the basis of a common comparator using meta-regression in order to derive an indirect comparison estimate, while preserving randomisation within trials. Assumptions of comparability were considered regarding study homogeneity (data can be pooled in a meta-analysis), similarity of trials (clinical and methodological) and consistency of findings from direct and indirect evidence.

RESULTS

The meta-analysis showed that TCF gel was statistically significantly more effective than other topical treatments in terms of achieving a response defined according to both IGA and TSS criteria. TCF gel was generally associated with a statistically significant lower risk of AEs, skin AEs or patients withdrawing from RCTs due to AEs.

CONCLUSIONS

Although direct and indirect evidence in this analysis is sparse, this indirect comparison suggests that the TCF gel has significant benefits over other topical therapies considered in the routine management of patients with moderately severe scalp psoriasis. Despite other analysis limitations in terms of study heterogeneity inevitable across an evidence base spanning decades, these results were consistent, using a number of efficacy and tolerability outcome measures.

Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network meta-analysis

OBJECTIVE

To determine the effect of glucosamine, chondroitin, or the two in combination on joint pain and on radiological progression of disease in osteoarthritis of the hip or knee. Design Network meta-analysis. Direct comparisons within trials were combined with indirect evidence from other trials by using a Bayesian model that allowed the synthesis of multiple time points.

MAIN OUTCOME MEASURE

Pain intensity. Secondary outcome was change in minimal width of joint space. The minimal clinically important difference between preparations and placebo was prespecified at -0.9 cm on a 10 cm visual analogue scale.

DATA SOURCES

Electronic databases and conference proceedings from inception to June 2009, expert contact, relevant websites. Eligibility criteria for selecting studies Large scale randomised controlled trials in more than 200 patients with osteoarthritis of the knee or hip that compared glucosamine, chondroitin, or their combination with placebo or head to head. Results 10 trials in 3803 patients were included. On a 10 cm visual analogue scale the overall difference in pain intensity compared with placebo was -0.4 cm (95% credible interval -0.7 to -0.1 cm) for glucosamine, -0.3 cm (-0.7 to 0.0 cm) for chondroitin, and -0.5 cm (-0.9 to 0.0 cm) for the combination. For none of the estimates did the 95% credible intervals cross the boundary of the minimal clinically important difference. Industry independent trials showed smaller effects than commercially funded trials (P=0.02 for interaction). The differences in changes in minimal width of joint space were all minute, with 95% credible intervals overlapping zero. Conclusions Compared with placebo, glucosamine, chondroitin, and their combination do not reduce joint pain or have an impact on narrowing of joint space. Health authorities and health insurers should not cover the costs of these preparations, and new prescriptions to patients who have not received treatment should be discouraged.

Pain relief for the removal of femoral sheath in interventional cardiology adult patients

BACKGROUND

There is considerable variation in use of pain relief for managing pain or discomfort of femoral sheath removal. Efficacy of pain relief to promote comfort during this procedure or to reduce the incidence of vascular and procedural complications has not been established.

OBJECTIVES

Assess efficacy of pain relief used to manage pain of femoral sheath removal in adults after interventional cardiology.Determine if pain relief influences rate of complications associated with this procedure.

SEARCH STRATEGY

Databases searched in August 2007: Cochrane Pain, Palliative and Supportive Care Group Trials Register, Cochrane Heart Group Trials Register, Cochrane CENTRAL, MEDLINE, EMBASE, CINAHL, PubMed, Australia's Australasian Medical Index, National Research Centre, Web of Knowledge and Digital Dissertations.

SELECTION CRITERIA

Randomised studies comparing opioid, local anaesthetic, anxiolytic, no treatment or placebo administered for alleviation of pain or discomfort of the femoral sheath removal procedure, were sought.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality and extracted data. Weighted mean differences (WMD) were calculated where meta-analysis of pain score data was feasible. Adverse effects information was collected.

MAIN RESULTS

Four trials involving 971 participants were included. All results were reported using a zero to ten pain scale. Three trials (four treatment arms) involving 498 participants compared subcutaneous lignocaine with control; with no significant difference between pain scores; WMD 0.12 (95% CI -0.46 to 0.69). Two trials (three treatment arms) involving 399 participants compared intravenous pain regimens with control. A significant reduction in pain score with an intravenous pain regimen (opioid and anxiolytic) was observed when compared with placebo; WMD -0.90 (95% CI -1.54 to -0.27). One study involving 60 participants compared levobupivacaine with placebo. Longer-acting local anaesthetic significantly lowered pain score by -1.10 (95% CI -1.26 to -0.94). Data is insufficient to identify any influence of pain regimens on incidence of vascular and procedural complications. No trials reported appropriate blinding for treatment arms. The largest trial, comprising 661 participants was unblinded with a quality score of two out of five.

AUTHORS' CONCLUSIONS

Intravenous pain regimens and levobupivacaine may have greater efficacy when compared to control for the management of pain related to femoral sheath removal. However, a definitive study is still required because the clinical difference is small. There is no evidence to support the use of subcutaneous lignocaine for the relief of femoral sheath removal related pain. There is insufficient evidence to determine if pain relief influences the rate of complications.