Importance of consistent outcomes in randomized controlled trials and systematic reviews about anesthesiology and pain

Reasons and factors associated with inconclusiveness of systematic reviews about interventions for neuropathic pain

Aim: Systematic reviews (SRs) are frequently inconclusive. The aim of this study was to analyze factors associated with conclusiveness of SRs about efficacy and safety of interventions for neuropathic pain (NeuP). Materials & methods: The study protocol was registered in the PROSPERO database (No. CRD42015025831). Five electronic databases (Medical Literature Analysis and Retrieval System Online, Cochrane Database of Systematic Reviews, Cumulative Index for Nursing and Allied Health Literature, Database of Abstracts of Reviews of Effects and Psychological Information Database) were searched until July 2018 for SRs about NeuP management. Conclusion statements for efficacy and safety, and characteristics of SRs were analyzed. Conclusiveness was defined as explicit statement by the SR authors that one intervention is better/similar to the other in terms of efficacy and safety. Methodological quality of SRs was assessed with the AMSTAR (A MeaSurement Tool to Assess systematic Reviews) tool. Results: Of 160 SRs, 37 (23%) were conclusive for efficacy and/or safety. In the SRs, conclusions about safety were missing in half of the analyzed abstracts, and a third of the full texts. Conclusive SRs included significantly more trials and participants, searched more databases, had more authors, conducted meta-analysis, analyzed quality of evidence, and had lower methodological quality than inconclusive SRs. The most common reasons for the lack of conclusiveness indicated by the SR authors were the small number of participants and trials, and the high heterogeneity of included studies. Conclusion: Most SRs about NeuP treatment were inconclusive. Sources of inconclusiveness of NeuP reviews need to be further studied, and SR authors need to provide conclusions about both safety and efficacy of interventions.

Reporting and analyses of sex/gender and race/ethnicity in randomized controlled trials of interventions published in the highest-ranking anesthesiology journals

Aim: We assessed reporting of data on sex/gender and race/ethnicity in randomized controlled trials of interventions published in the highest-ranking anesthesiology journals from 2014 to 2017. Methods: We extracted data regarding terminology for sex/gender, proportion of participants according to the race/gender and race/ethnicity, and results shown for the race/gender and race/ethnicity. Results: Among the analyzed 732 trials, few stratified allocation of participants on the basis of sex/gender and race/ethnicity, few reported results for sex/gender or race/ethnicity and the outcomes reported may be influenced by one or both. Conclusion: In conclusion, outcomes of anesthesiology trials could be vulnerable to an important and avoidable source of bias; trialists need to pay more attention to sex and race/ethnicity when designing and reporting their studies.

Selective reporting bias due to discrepancies between registered and published outcomes in osteoarthritis trials

Aim: Outcome reporting bias (ORB) occurs when outcomes planned in a study protocol are subsequently not reported or are partially reported. Our aim was to analyze ORB in randomized controlled trials (RCTs) about conservative interventions for osteoarthritis (OA) by comparing registered protocols and published manuscripts, as well as association between study funding type and intervention type, and ORB in those RCTs. Materials & methods: We analyzed RCTs that were published in a peer-review journal and analyzed any type of conservative intervention for treatment of OA in humans that reported in the manuscript registration in a public clinical trial registry and provided unique registration identifier. We extracted data indicating ORB by comparing outcomes in protocol and published article, and characteristics of trials. Results: In 190 (57%) of 334 included RCTs, it was indicated in the manuscript that a trial was registered. In 48% of trials we found discrepancies in number, type or time point of primary efficacy outcome between protocol and manuscript. Significantly less discrepancies in primary efficacy outcomes between protocols and published articles were found in trials funded by a commercial sponsor (p = 0.0062) and trials of pharmacological interventions (p = 0.0016). Conclusion: Trials about conservative therapies for OA have high prevalence of discrepancies between protocol and publication, and frequent ORB. This may mislead readers of published results because it has been shown that ORB can lead to both overestimation and underestimation of effects of interventions, depending on the intervention and outcome. Efforts to prevent nonregistration of protocols and selective reporting are needed.

Adductor canal blocks for postoperative pain treatment in adults undergoing knee surgery

BACKGROUND

Peripheral regional anaesthesia techniques are well established for postoperative pain treatment following knee surgery. The adductor canal block (ACB) is a new technique, which can be applied as a single shot or by catheter for continuous regional analgesia.

OBJECTIVES

To compare the analgesic efficacy and adverse events of ACB versus other regional analgesic techniques or systemic analgesic treatment for adults undergoing knee surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase, five other databases, and one trial register on 19 September 2018; we checked references, searched citations, and contacted study authors to identify additional studies.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) comparing single or continuous ACB versus other regional analgesic techniques or systemic analgesic treatment. Inclusion was independent of the technique used (landmarks, peripheral nerve stimulator, or ultrasound) and the level of training of providers.

DATA COLLECTION AND ANALYSIS

We used Cochrane's standard methodological procedures. Our primary outcomes were pain intensity at rest and during movement; rate of accidental falls; and rates of opioid-related adverse events. We used GRADE to assess the quality of evidence for primary outcomes.

MAIN RESULTS

We included 25 RCTs (1688 participants) in this review (23 trials combined within meta-analyses). In 18 studies, participants underwent total knee arthroplasty (TKA), whereas seven trials investigated patients undergoing arthroscopic knee surgery. We identified 11 studies awaiting classification and 11 ongoing studies. We investigated the following comparisons. ACB versus sham treatment We included eight trials for this comparison. We found no significant differences in postoperative pain intensity at rest (2 hours: standardized mean difference (SMD) -0.56, 95% confidence interval (CI) -1.20 to 0.07, 4 trials, 208 participants, low-quality evidence; 24 hours: SMD -0.49, 95% CI -1.05 to 0.07, 6 trials, 272 participants, low-quality evidence) or during movement (2 hours: SMD -0.59, 95% CI -1.5 to 0.33; 3 trials, 160 participants, very low-quality evidence; 24 hours: SMD 0.03, 95% CI -0.26 to 0.32, 4 trials, 184 participants, low-quality evidence). Furthermore, they noted no evidence of a difference in postoperative nausea between groups (24 hours: risk ratio (RR) 1.91, 95% CI 0.48 to 7.58, 3 trials, 121 participants, low-quality evidence). One trial reported that no accidental falls occurred 24 hours postoperatively (low-quality evidence). ACB versus femoral nerve block We included 15 RCTs for this comparison. We found no evidence of a difference in postoperative pain intensity at rest (2 hours: SMD -0.74, 95% CI -1.76 to 0.28, 5 trials, 298 participants, low-quality evidence; 24 hours: SMD 0.04, 95% CI -0.09 to 0.18, 12 trials, 868 participants, high-quality evidence) or during movement (2 hours: SMD -0.47, 95% CI -1.86 to 0.93, 2 trials, 88 participants, very low-quality evidence; 24 hours: SMD 0.56, 95% CI -0.00 to 1.12, 9 trials, 576 participants, very low-quality evidence). They noted no evidence of a difference in postoperative nausea (24 hours: RR 1.22, 95% CI 0.42 to 3.54, 2 trials, 138 participants, low-quality evidence) and no evidence that the rate of accidental falls during postoperative care was significantly different between groups (24 hours: RR 0.20, 95% CI 0.04 to 1.15, 3 trials, 172 participants, low-quality evidence).

AUTHORS' CONCLUSIONS

We are currently uncertain whether patients treated with ACB suffer from lower pain intensity at rest and during movement, fewer opioid-related adverse events, and fewer accidental falls during postoperative care compared to patients receiving sham treatment. The same holds true for the comparison of ACB versus femoral nerve block focusing on postoperative pain intensity. The overall evidence level was mostly low or very low, so further research might change the conclusion. The 11 studies awaiting classification and the 11 ongoing studies, once assessed, may alter the conclusions of this review.

Awareness and acceptability of Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials core outcome set for chronic pain among surveyed neuropathic pain authors

Aim: We assessed the knowledge and adoption of Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT)-recommended core outcome set (COS) and core outcome measures (COM) among authors of systematic reviews (SR) and randomized controlled trials (RCT) about interventions for neuropathic pain (NeuP). Methods: NeuP SR and RCT authors identified via a systematic literature search were surveyed. Results: The response rate was low. Although majority of respondents were familiar with the IMMPACT COS, only 61% of SR authors and 40% of RCT authors used the COS. The main perceived obstacle that prevented the adoption of the COS was the lack of awareness of the full IMMPACT COS. Conclusion: The adoption of IMMPACT-recommended COS and COM among NeuP authors was inadequate and their appropriateness needs to be further evaluated.