Association of a standardized painless ward model with cancer pain control and hospitalization outcomes: a retrospective cohort study

In reply:

What decline in pain intensity is meaningful to patients with acute pain?

Baseline pain characteristics predict pain reduction after physical therapy in women with chronic pelvic pain. Secondary analysis of data from a randomized controlled trial.

The lack of established minimum clinically important differences in acute pain has made it challenging to interpret efficacy in analgesic trials. We performed a patient-level re-analysis of double-blind, placebo-controlled trials submitted to the US Food and Drug Administration to estimate minimum clinically important differences in acute postoperative pain. Trials were categorized by acute surgical pain model: dental extraction, bunionectomy, orthopedic surgery, and soft tissue surgery. Pain intensity was assessed using the 0 to 10 numeric rating scale (NRS) or 0 to 100 visual analog scale, with visual analog scale scores converted to NRS for analysis. To avoid misclassification from arbitrary thresholds on global impression of change or pain relief scales, meaningful pain relief was determined using the double-stopwatch technique, where patients actively indicated the times they experienced perceptible and meaningful relief. Across 29 trials, 9047 patients with moderate-to-severe baseline pain were included. Patients with severe baseline pain (NRS ≥7) reported meaningful relief at a higher absolute NRS and required larger absolute reductions in pain intensity than those with moderate baseline pain (NRS 4-<7). However, the percent reduction in pain at meaningful relief remained stable across baseline pain levels, suggesting patients assess meaningful relief in relative rather than absolute terms. No appreciable differences in the changes in pain at meaningful relief were observed by age, sex, drug, or route of administration. Receiver operating characteristic curve analysis identified a 50% reduction in pain intensity as a consistent and clinically meaningful threshold across surgical pain models, supporting its use as a standardized patient-centric metric for evaluating analgesic efficacy.

ObjectiveThis secondary analysis of a randomised controlled patient-blinded trial comparing effectiveness and side effect briefings in patients with chronic low back pain (CLBP) investigated the association between patients’ pre-treatment expectations about minimal acupuncture treatment and pain intensity as outcome during and after the end of the treatment.MethodsChronic low back pain patients with a pain intensity of at least 4 on a numeric rating scale from 0 to 10 received eight sessions of minimal acupuncture treatment over 4 weeks. The primary outcome was change in pain intensity rated on a Numerical Rating Scale (NRS 0–10) from inclusion visit to treatment session 4 and to the end of the treatment. Patients’ expectations about the effectiveness of acupuncture were assessed using the Expectation for Treatment Scale (ETS) before randomization. Linear regression was applied to investigate whether patients’ pre-treatment expectations predicted changes in pain intensity during and after treatment.ResultsA total of 142 CLBP patients (40.1 ± 12.5 years; 65.5% female) were included in our analysis. Patients’ pre-treatment expectations about acupuncture treatment were associated with changes in pain intensity after four sessions of minimal acupuncture treatment (b = -0.264, p = 0.002), but not after the end of the treatment. This association was found in females and males.ConclusionsOur results imply that higher pre-treatment expectations only lead to larger reductions in pain intensity in the initial phase of a treatment, with a similar magnitude for both females and males. As the treatment progresses in the second half of the treatment, adapted expectations or other non-specific effects might play a more important role in predicting treatment outcome.

The aim of this review was to systematically identify all evidence that used conventional medical management (CMM) as a comparator in randomized controlled trials (RCTs) of spinal cord stimulation (SCS) therapy, and to conduct a meta-analysis to investigate if continued CMM provides statistical or clinically meaningful pain relief and whether CMM effects have improved over the last few decades. Databases were searched from inception to June 2024 for RCTs that compared SCS to CMM. The primary outcome of the review was absolute change in pain intensity from baseline to the last available follow-up in the CMM group, measured using a visual analogue scale or numerical rating scale. The measure of treatment effect for absolute change and percentage change in pain intensity from baseline was mean difference (MD) and 95% confidence interval (CI). Risk of bias (RoB) was assessed by using the revised Cochrane RoB tool. The protocol for this review is registered on PROSPERO (CRD42023449215). Meta-analysis of absolute change in pain intensity from baseline to last follow-up shows that CMM is not associated with any significant reductions in pain intensity (MD -0.11; 95% CI: -0.32 to 0.11; moderate certainty). Similar results were observed for percent change in pain intensity from baseline to last follow-up (MD -3.22%; 95% CI: -12.59% to 6.14%; moderate certainty). No significant differences were observed when considering decade of publication of the RCT for absolute (P = .065; moderate certainty) or percent change in pain intensity (P = 0.524; moderate certainty). Meta-analysis for 6-month follow-up and sensitivity analysis shows similar numerical results. Our findings show that continued CMM for a population eligible for SCS does not provide meaningful pain relief and has not considerably changed over the last few decades. The use of CMM as the control to evaluate relative SCS treatment effects should be reassessed.

Pregabalin beneficial effects on sleep quality or health-related quality of life are poorly correlated with reduction on pain intensity

Secondary analysis of pooled data from 3 randomized trials. This study investigated sex differences in response to physical therapy intervention for acute low back pain. Sex differences in experimental pain sensitivity have been consistently described in the literature. However, clinical consequences of these sex differences have not been widely reported. Subjects (n=165) were participants in 3 randomized trials of physical therapy interventions from outpatient physical therapy clinics in the general and military communities. Subjects were randomly assigned spinal manipulation with range-of-motion exercise, lumbar stabilization exercise, or directional-preference exercise. Outcomes were measured at 4 weeks through self-report of pain intensity and pain-related disability. Sex differences were investigated with independent t tests (baseline data), 2 x 3 analysis of variance (4-week reductions in pain and pain-related disability), and regression models (predictors of outcome). Men and women had similar reductions of pain intensity (raw mean difference, 0.5; 95% Cl, -1.4 to 0.4) and pain-related disability (raw mean difference, 5.3; 95% CI, -0.1 to 10.7) over 4 weeks. Baseline pain intensity, duration of symptoms, and baseline pain-related disability significantly predicted change in pain intensity for women (r2 = 26%, P < .01). Baseline pain intensity and stabilization exercise predicted change in pain intensity for men (r2 = 33%, P<.01). Baseline pain-related disability, duration of pain, and pain intensity predicted change in disability for women (r2 = 24%, P < .01). Baseline pain-related disability, fear-avoidance beliefs, stabilization exercise, and leg pain predicted change in disability for men (r2 = 32%, P < .01). For patients with acute low back pain, men and women had similar physical therapy outcomes for reductions in pain intensity and pain-related disability. However, men and women had different factors that predicted treatment outcome.

Low-dose ketamine has been used perioperatively for pain control and may be a useful adjunct to intravenous (IV) opioids in the control of acute pain in the emergency department (ED). The aim of this study was to determine the effectiveness of low-dose ketamine as an adjunct to morphine versus standard care with morphine alone for the treatment of acute moderate to severe pain among ED patients. A double-blind, randomized, placebo-controlled trial with three study groups was conducted at a large, urban academic ED over a 10-month period. Eligible patients were 18 to 65 years old with acute moderate to severe pain (score of at least 5 out of 10 on the numerical pain rating scale [NRS] and pain duration < 7 days) who were deemed by their treating physician to require IV opioids. The three study groups were: 1) morphine and normal saline placebo (standard care group), 2) morphine and 0.15 mg/kg ketamine (group 1), or 3) morphine and 0.3 mg/kg ketamine (group 2). Participants were assessed at 30, 60, and 120 minutes after study medication administration and received rescue analgesia as needed to target a 50% reduction in pain. The primary outcome measure of pain relief, or pain intensity reduction, was derived using the NRS and calculated as the summed pain-intensity (SPID) difference over 2 hours. The amount and timing of rescue opioid analgesia was evaluated as a secondary outcome. The occurrence of adverse events was also measured. Sixty patients were enrolled (n = 20 in each group). There were no differences between study groups with respect to age, sex, race/ethnicity, preenrollment analgesia, or baseline NRS. Over the 2-hour poststudy medication administration period, the SPIDs were higher (greater pain relief) for the ketamine study groups than the control group (standard care 4.0, interquartile range [IQR] = 1.8 to 6.5; group 1 7.0, IQR = 4.3 to 10.8; and group 2 7.8, IQR = 4.8 to 12.8; p < 0.02). The SPIDs for the ketamine groups were similar (p < 0.46). When compared to standard care, group 2 sustained the reduction in pain intensity up to 2 hours, whereas group 1 was similar to standard care by 2 hours. Similar numbers of patients received rescue analgesia: standard care group, seven of 20, 35%; group 1, four of 20, 20%; and group 2, four of 20, 20% (p = 0.48). Among those receiving rescue analgesia, those in the standard care group received analgesia sooner than either low-dose ketamine group, on average. More participants in the low-dose ketamine groups reported dysphoria and dizziness. Low-dose ketamine is a viable analgesic adjunct to morphine for the treatment of moderate to severe acute pain. Dosing of 0.3 mg/kg is possibly more effective than 0.15 mg/kg, but may be associated with minor adverse events. Future studies should evaluate additional outcomes, optimum dosing, and use in specific populations.

Management of pain in the pre-hospital setting is often inadequate. In 2011, ambulance personnel were authorized to administer intravenous fentanyl in the Central Denmark Region. The aim of this study was to evaluate the efficacy and safety of intravenous fentanyl administered by ambulance personnel. Pre-hospital medical charts from 2348 adults treated with intravenous fentanyl by ambulance personnel during a 6-month period were reviewed. The primary outcome was the change in pain intensity on a numeric rating scale (NRS) from before fentanyl treatment to hospital arrival. Secondary outcomes included the number of patients with reduction in pain intensity during transport (NRS ≥ 2), the number of patients with NRS > 3 at hospital arrival, and potential fentanyl-related side effects. Fentanyl reduced pain from before treatment (8, IQR 7-9) to hospital arrival (4, IQR 3-6) (NRS reduction: 3, IQR 2-5; P = 0.001), 79.3% of all patients had a reduction in > 2 on the NRS during transport, and 58.4% of patients experienced pain at hospital arrival (NRS > 3). Twenty-one patients (0.9%) had oxygen saturation < 90%. A decrease in Glasgow Coma Scale was seen in 31 patients (1.3%) and hypotension observed in 71 patients (3.0%). Intravenous fentanyl caused clinically meaningful pain reduction in most patients and was safe in the hands of ambulance personnel. Many patients had moderate to severe pain at hospital arrival. As the protocol allowed higher doses of fentanyl, feedback on effect and safety should be part of continuous education of ambulance personnel.

SAT0452 Do Traditional Risk Factors for Knee Osteoarthritis Predict Pain Flares in Knee Osteoarthritis?

Chronic intractable pain from peripheral neuropathy is a debilitating condition that might not respond to conventional medical management and pharmacotherapy. The primary objective of this systematic review was to assess change (or reduction) in pain intensity in patients with length-dependent peripheral neuropathy after spinal cord stimulation (SCS) therapy. This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The primary outcome was change (or reduction) in pain intensity after 12 months of SCS therapy compared with baseline in participants with length-dependent peripheral neuropathy. Secondary outcomes included change in pain intensity after 6 months and change in opioid consumption after 12 months. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines were used to appraise the quality of evidence. Nineteen studies consisting of 376 participants who underwent SCS implantation met the inclusion criteria. Qualitative synthesis revealed that all eligible studies reported a significant improvement in pain intensity after 12 months of SCS therapy as compared with baseline. Mean differences with 95% confidence intervals were calculated for 4 studies, all of which achieved the minimal clinically important difference for change in pain intensity at 12 months. The GRADE quality of evidence for this outcome was appraised as very low quality. This systematic review highlights that SCS could lead to significant improvement in pain intensity for length-dependent peripheral neuropathy, although future well-powered randomized controlled trials are warranted to increase the certainty of evidence in this finding. PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) ID: CRD42022377572.

Ultrasound-guided radiofrequency Ablation for SI joint pain:An observational study

PurposeThis study aimed to investigate whether changes in psychosocial factors and pain severity were associated with reduction in disability due to pain among patients with chronic pain. We hypothesized that increased self-efficacy would reduce disability.Patients and methodsThis longitudinal observational study included 72 patients. Patients’ psychological and physical variables were assessed before and after 3 months of treatment. Demographic and clinical information were collected, including the Pain Disability Assessment Scale (PDAS), the Pain Self-Efficacy Questionnaire (PSEQ), the Hospital Depression and Anxiety Scale, and the Numeric Rating Scale (NRS) to assess pain intensity. First, univariate regression analyses were conducted to clarify associations between change in PDAS and sex, age, pain duration, changes in psychosocial factors (self-efficacy, anxiety, and depression) and change in pain intensity. Second, multivariate regression was conducted using the variables identified in the univariate analyses (PSEQ and NRS) to detect the most relevant factor for reducing disability.ResultsUnivariate regression analyses clarified that changes in PSEQ (β = −0.31; 95% CI: −0.54–−0.08, p = 0.008) and NRS (β = 0.24; 95% confidence interval [CI]: 0.01–0.47, p = 0.04) were associated with reduction in PDAS. Multivariate regression analysis demonstrated that change in PSEQ (β = 0.26; 95% CI: −0.50–−0.02; p = 0.01) was associated with a reduction in disability, independent of change in NRS.ConclusionThese findings suggest improved self-efficacy is associated with reduced disability in patients with chronic pain, independent of reduction in pain intensity. Focusing on improvement in self-efficacy may be an effective strategy in chronic pain treatment in addition to pain relief.

Pregabalin (PGB) has been shown to improve sleep quality and health-related quality of life (HRQoL) as well as pain intensity in patients with neuropathic pain. The objective of the study was to explore the magnitude of the correlations between changes in pain intensity, sleep quality, and HRQoL after PGB treatment. One hundred thirty-eight patients with neuropathic pain of any origin and without an adequate response to analgesics received an 8-week treatment course of PGB in an open-label fashion. Pain intensity, sleep quality, and HRQoL outcomes were evaluated at baseline and at week 8 by means of an 11-point (0-10) numerical rating scale (NRS), the Pittsburgh Sleep Quality Index (PSQI), and the EuroQol health-state visuoanalogic scale (EQ-5D VAS) score, respectively. At week 8, mean PGB dose was 166.7 ± 7.8 mg/d. Pain intensity NRS score, PSQI total score, and EQ-5D VAS score were improved by 66.5% ± 1.9%, 40.0% ± 3.6%, and 26.4% ± 4.7% (all P < 0.01), respectively. Correlations between percent change from baseline in pain NRS score and PSQI total score or EQ-5D VAS scores were r = 0.36 (P < 0.01, R = 0.11) and r = -0.20 (P < 0.02, R = 0.05), respectively. A multivariate logistic regression analysis disclosed that PSQI score change below the median (ie, a better outcome) was related to higher EQ-5D VAS score change (odds ratio, 2.15; 95% confidence interval, 1.09-4.25), whereas pain intensity NRS score change below the median was not (odds ratio, 1.58; 95% confidence interval,0.78-3.23). In our study, PGB-related improvements in sleep quality and HRQoL were marginally related to reductions in pain intensity in patients with neuropathic pain. Improvement in sleep quality was a significant predictor of better HRQoL, whereas pain intensity reduction was not.