Dexamethasone and persistent wound pain: a prespecified analysis of the randomised Perioperative Administration of Dexamethasone and Infection (PADDI) trial

Intraoperative dexamethasone and chronic postsurgical pain: a propensity score-matched analysis of a large trial

BACKGROUND

Dexamethasone has been shown to reduce acute pain after surgery, but there is uncertainty as to its effects on chronic postsurgical pain (CPSP). We hypothesised that in patients undergoing major noncardiac surgery, a single intraoperative dose of dexamethasone increases the incidence of CPSP.

METHODS

We devised a propensity score-matched analysis of the ENIGMA-II trial CPSP dataset, aiming to compare the incidence of CPSP in patients who had received dexamethasone or not 12 months after major noncardiac surgery. The primary outcome was the incidence of CPSP. We used propensity score matching and inverse probability weighting to balance baseline variables to estimate the average marginal effect of dexamethasone on patient outcomes, accounting for confounding to estimate the average treatment effect on those treated with dexamethasone.

RESULTS

We analysed 2999 patients, of whom 116 of 973 (11.9%) receiving dexamethasone reported CPSP, and 380 of 2026 (18.8%) not receiving dexamethasone reported CPSP, unadjusted odds ratio 0.76 (95% confidence interval 0.78-1.00), P=0.052. After propensity score matching, CPSP occurred in 116 of 973 patients (12.2%) receiving dexamethasone and 380 of 2026 patients (13.8%) not receiving dexamethasone, adjusted risk ratio 0.88 (95% confidence interval 0.61-1.27), P=0.493. There was no difference between groups in quality of life or pain interference with daily activities, but 'least pain' (P=0.033) and 'pain right now' (P=0.034) were higher in the dexamethasone group.

CONCLUSIONS

Dexamethasone does not increase the risk of chronic postsurgical pain after major noncardiac surgery.

CLINICAL TRIAL REGISTRATION

Open Science Framework Registration DOI https://doi.org/10.17605/OSF.IO/ZDVB5.

Dexamethasone and chronic postsurgical pain: the pendulum meets reductionistic thinking

Reductionist thinking results in the bulk of anaesthesia trial designs being a single intervention to address what are in fact complex processes. The Perioperative Administration of Dexamethasone and Infection (PADDI) trial assessed the safety of a single preoperative dose of dexamethasone. Surprising to most, in the original report, a single dose of dexamethasone increased the incidence of the secondary outcome chronic postsurgical pain. Was this a chance finding or does dexamethasone increase chronic postsurgical pain? In an attempt to address this question, the PADDI investigators have now analysed this prespecified secondary outcome in two ways: as a substudy published earlier in this Journal, and as a retrospective analysis of the ENIGMA-II chronic pain database in this issue of the Journal. The PADDI investigators have now presented enough data to convince us that indeed a single dose of dexamethasone is safe and effective. However, the increase in chronic postsurgical pain seen in the original PADDI publication highlights the complexities, and the possible immunologic mechanisms, behind the genesis of chronic postsurgical pain. These publications from the PADDI group raise questions about other anti-inflammatory agents we use regularly for long-term postoperative pain management, and highlights the need for well-designed clinical trials to address this critically important patient-centred adverse functional outcome.

Basic analgesic use in randomised trials assessing local and regional analgesic interventions for mastectomy: a critical appraisal and clinical implications

Regional analgesia is a core component of an optimal multimodal analgesia technique. Several advanced regional analgesic techniques have been evaluated for mastectomy; however, the optimal choice remains unclear. Many randomised clinical trials (RCTs) evaluating various local/regional analgesic techniques do not include basic analgesics (i.e. paracetamol, non-steroidal anti-inflammatory drugs, cyclooxygenase-2 specific inhibitors, and dexamethasone) which precludes objective evaluation of their efficacy. The aim of this scoping review was to assess the use of basic analgesics in RCTs evaluating efficacy of local and regional analgesic techniques in patients undergoing mastectomy. PubMed was searched to identify relevant articles from January 1, 2010 to May 31, 2023. The key finding of this study is that almost 90% (n=82/92) of the RCTs evaluating local/regional analgesic techniques in patients undergoing mastectomy did not administer well accepted basic analgesics in the comparator groups. Consequently, the conclusions of the RCTs assessing local/regional analgesic techniques for mastectomy should be interpreted with caution. Also, clinical guidelines based on meta-analyses of these RCTs could be inadequate or inappropriate.