Use of patient-reported global assessment measures in clinical trials of chronic pain treatments: ACTTION systematic review and considerations

ABSTRACT

Establishing clinically meaningful changes in pain experiences remains important for clinical trials of chronic pain treatments. Regulatory guidance and pain measurement initiatives have recommended including patient-reported global assessment measures (eg, Patient-Global Impression of Change [PGIC]) to aid interpretation of within-patient differences in domain-specific clinical trial outcomes (eg, pain intensity). The objectives of this systematic review were to determine the frequency of global assessment measures inclusion, types of measures, domains assessed, number and types of response options, and how measures were analyzed. Of 4172 abstracts screened across 6 pain specialty journals, we reviewed 96 clinical trials of chronic pain treatments. Fifty-two (54.2%) studies included a global assessment measure. The PGIC was most common (n = 28; 53.8%), with relatively infrequent use of other measures. The majority of studies that used a global assessment measure (n = 31; 59.6%) assessed change or improvement in an unspecified domain. Others assessed overall condition severity (n = 9; 17.3%), satisfaction (n = 8; 15.4%), or overall health status/recovery (n = 5; 9.6%). The number, range, and type of response options were variable and frequently not reported. Response options and reference periods even differed within the PGIC. Global assessment measures were most commonly analyzed as continuous variables (n = 24; 46.2%) or as dichotomous variables with positive categories combined to calculate the proportion of participants with a positive response to treatment (n = 18; 34.6%). This review highlights the substantial work necessary to clarify measurement and use of patient global assessment in chronic pain trials and provides short- and long-term considerations for measure selection, reporting and analysis, and measure development.

Effect size varies based on calculation method and may affect interpretation of treatment effect: an illustration using randomised clinical trials in osteoarthritis

BACKGROUND

To illustrate how (standardised) effect sizes (ES) vary based on calculation method and to provide considerations for improved reporting.

METHODS

Data from three trials of tanezumab in subjects with osteoarthritis were analyzed. ES of tanezumab versus comparator for WOMAC Pain (outcome) was defined as least squares difference between means (mixed model for repeated measures analysis) divided by a pooled standard deviation (SD) of outcome scores. Three approaches to computing the SD were evaluated: Baseline (the pooled SD of WOMAC Pain values at baseline [pooled across treatments]); Endpoint (the pooled SD of these values at the time primary endpoints were assessed); and Median (the median pooled SD of these values based on the pooled SDs across available timepoints). Bootstrap analyses were used to compute 95% confidence intervals (CI).

RESULTS

ES (95% CI) of tanezumab 2.5 mg based on Baseline, Endpoint, and Median SDs in one study were - 0.416 (- 0.796, - 0.060), - 0.195 (- 0.371, - 0.028), and - 0.196 (- 0.373, - 0.028), respectively; negative values indicate pain improvement. This pattern of ES differences (largest with Baseline SD, smallest with Endpoint SD, Median SD similar to Endpoint SD) was consistent across all studies and doses of tanezumab.

CONCLUSION

Differences in ES affect interpretation of treatment effect. Therefore, we advocate clearly reporting individual elements of ES in addition to its overall calculation. This is particularly important when ES estimates are used to determine sample sizes for clinical trials, as larger ES will lead to smaller sample sizes and potentially underpowered studies.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02697773, NCT02709486, and NCT02528188.

Does sex affect the efficacy of systemic pharmacological treatments of pain in knee osteoarthritis? A systematic review

Objective

To determine whether sex influences the analgesic efficacy of systemic pharmacological treatment in patients with knee osteoarthritis.

Design

A systematic review, guided by Cochrane methods, sourced studies from Medline, Cochrane Library, Embase, and CINAHL Plus with Full Text as of October 10, 2022. Eligible studies were double-blind RCTs evaluating systemic pharmacological treatments for knee osteoarthritis in adults, with minimum 30-day treatment duration, reporting sex-specific results or mentioning sex subgroup analysis for analgesic efficacy. The risk of bias was assessed using the Cochrane Risk of Bias tool version 2 (RoB 2).

Results

9 studies (5201 participants) met inclusion criteria, analyzing drugs including duloxetine, etoricoxib, tapentadol, naproxcinod, lutikizumab, and rofecoxib. Only one study reported sex-specific results. Review findings suggested no significant sex-based differences in treatment efficacy, however, data were limited due to a lack of sex-specific reporting or inclusion of sex in subgroup analyses.

Conclusions

Current evidence does not support the existence of sex differences in the analgesic efficacy of systemic knee osteoarthritis treatments. However, this conclusion is substantially limited by the paucity of sex-specific reporting of results or subgroup analyses in most primary studies, emphasizing the need for future research to report on sex-stratified data to allow for comprehensive, personalized treatment strategies.

Neuropsychology of chronic back pain managed with long-term opioid use

Chronic pain is commonly treated with long-term opioids, but the neuropsychological outcomes associated with stable long-duration opioid use remain unclear. Here, we contrasted the psychological profiles, brain activity, and brain structure of 70 chronic back pain patients on opioids (CBP+O, average opioid exposure 6.2 years) with 70 patients managing their pain without opioids. CBP+O exhibited moderately worse psychological profiles and small differences in brain morphology. However, CBP+O had starkly different spontaneous brain activity, dominated by increased mesocorticolimbic and decreased dorsolateral-prefrontal activity, even after controlling for pain intensity and duration. These differences strongly reflected cortical opioid and serotonin receptor densities and mapped to two antagonistic resting-state circuits. The circuits' dynamics were explained by mesocorticolimbic activity and reflected negative affect. We reassessed a sub-group of CBP+O after they briefly abstained from taking opioids. Network dynamics, but not spontaneous activity, reflected exacerbated signs of withdrawal. Our results have implications for the management and tapering of opioids in chronic pain.

Subcortical brain anatomy as a potential biomarker of persistent pain after total knee replacement in osteoarthritis

ABSTRACT

The neural mechanisms for the persistence of pain after a technically successful arthroplasty in osteoarthritis (OA) remain minimally studied, and direct evidence of the brain as a predisposing factor for pain chronicity in this setting has not been investigated. We undertook this study as a first effort to identify presurgical brain and clinical markers of postarthroplasty pain in knee OA. Patients with knee OA (n = 81) awaiting total arthroplasty underwent clinical and psychological assessment and brain magnetic resonance imagining. Postoperative pain scores were measured at 6 months after surgery. Brain subcortical anatomic properties (volume and shape) and clinical indices were studied as determinants of postoperative pain. We show that presurgical subcortical volumes (bilateral amygdala, thalamus, and left hippocampus), together with shape deformations of the right anterior hippocampus and right amygdala, associate with pain persistence 6 months after surgery in OA. Longer pain duration, higher levels of presurgical anxiety, and the neuropathic character of pain were also prognostic of postsurgical pain outcome. Brain and clinical indices accounted for unique influences on postoperative pain. Our study demonstrates the presence of presurgical subcortical brain factors that relate to postsurgical persistence of OA pain. These preliminary results challenge the current dominant view that mechanisms of OA pain predominantly underlie local joint mechanisms, implying novel clinical management and treatment strategies.

Zoledronic acid after spinal cord injury mitigates losses in proximal femoral strength independent of ambulation ability

Rapid bone loss can occur after spinal cord injury (SCI) and a standard of care to prevent or treat this phenomenon is an active area of research. Using advanced analysis techniques, this study demonstrates that zoledronic acid, a possible treatment, prevented loss of bone strength at the hip following SCI.

INTRODUCTION

Bone loss below the level of neurological lesion is a well-known complication of spinal cord injury (SCI), and effective preventive treatment for this phenomenon is an active area of research. Zoledronic acid has demonstrated efficacy to attenuate bone loss at the hip after SCI, but previous studies relied on measurements from dual-energy X-ray absorptiometry. The purpose of this investigation was to more thoroughly characterize changes to bone mineral and strength at the proximal femur in individuals receiving zoledronic acid in the acute SCI stage; we also examined the influence of ambulatory ability on bone outcomes.

METHODS

Participants randomized to either zoledronic acid (n = 29) or placebo (n = 30) received computed tomography (CT) scans and ambulatory assessments at baseline and 6 and 12 months following drug infusion. CT-based finite element (FE) modeling was used to predict changes in proximal femoral strength associated with treatment.

RESULTS

After 12 months, FE-predicted bone strength was reduced by a mean (SD) of 9.6 (17.9)% in the zoledronic acid group versus 24.6 (24.5)% in the placebo group (p = 0.007). These differences in strength were explained by reductions in CT measurements of both trabecular (p < 0.001) and cortical (p ≤ 0.021) bone at the femoral neck and trochanteric region. Ambulation ability influenced select trabecular and cortical parameters, but we were unable to detect an impact on FE-predicted bone strength.

CONCLUSION

These findings demonstrate that treatment with zoledronic acid in acute SCI attenuates losses in proximal femoral strength, which may reduce the risk of hip fractures across patients with varying degrees of ambulatory abilities.

Bone Mineral Loss at the Distal Femur and Proximal Tibia Following Spinal Cord Injury in Men and Women

PURPOSE

Spinal cord injury (SCI) causes rapid bone loss and increases risk of fragility fractures in the lower extremities. The majority of individuals with SCI are men, and few studies have investigated sex as a biological variable in SCI-induced osteoporosis. This cross-sectional study aimed to quantify sex-specific differences in bone mineral following SCI.

METHODS

Quantitative computed tomography (QCT) scans of the distal femur and proximal tibia were obtained at baseline of one of four clinical trials enrolling people who sustained SCI 1 month to 50 years prior to recruitment. Bone volume (BV), bone mineral content (BMC), bone mineral density (BMD), and bending strength index (BSI) were quantified in the integral, trabecular, and cortical bone in the epiphysis, metaphysis and diaphysis. Scans from 106 men and 31 women were analyzed to measure sex-specific effects on bone loss over time post-SCI.

RESULTS

BMC and BSI declined exponentially as a function of time post-SCI and were best described by separate decay curves for men and women. Women had BV, BMC, and BSI at 58-77% that of men in the acute and plateau phases, with both sexes showing similar rates of loss as a function of time post-SCI. Trabecular BMD was best described as an exponential decay versus time post-SCI, with no sex-specific differences.

CONCLUSIONS

Due to consistently lower BV, BMC, and BSI, women may be more susceptible to fractures after SCI than men.

Opioids for Osteoarthritis: Cross-Sectional Survey of Patient Perspectives and Satisfaction

Patients often take opioids to relieve osteoarthritis (OA) pain despite limited benefits and potential harms. This study aimed to compare cross-sectional perspectives of patients that were taking prescription opioid (N = 471) or nonopioid medications (N = 185) for OA in terms of satisfaction, expectations of effectiveness, and concerns. Patients prescribed opioids (>7 days) reported more prior treatments (2.47 vs. 1.74), greater mean pain intensity (5.47 vs. 4.11), and worse quality of life (EQ-5D-5L index value mean 0.45 vs. 0.71) than patients prescribed nonopioid medications (all p < 0.0001). Based on linear regression models adjusting for demographics and pain intensity, patients prescribed opioids were less satisfied with overall regimen (3.40 vs. 3.67, p = 0.0322), had less belief that medications were meeting effectiveness expectations (2.72 vs. 3.13, p < 0.0001), and had more concerns about treatments being "not very good" (3.66 vs. 3.22, p = 0.0026) and addiction (3.30 vs. 2.65, p < 0.0001) than patients prescribed nonopioid regimens. When the models were replicated for subgroups with ≥30 days' medication regimen duration, the findings were consistent with the main analyses. Patients have concerns about the risk of opioid addiction, but those with greater disease burden and more prior treatments continue taking opioid regimens.

Opioid Prescribing for Osteoarthritis: Cross-Sectional Survey among Primary Care Physicians, Rheumatologists, and Orthopaedic Surgeons

Opioids are often prescribed for osteoarthritis (OA) pain, despite recommendations to limit use due to minimal benefits and associated harms. This study aimed to assess physicians' practice patterns and perceptions regarding opioids by specialty one year following the Centers for Disease Control and Prevention (CDC) published guidance on opioid prescribing. The 139/153 (90.8%) physicians who reported prescribing opioids in the previous year reported decreased prescribing for mild OA (51.3%, 26.5% and 33.3% of primary care physicians, rheumatologists, and orthopaedic surgeons, respectively), moderate OA (50.0%, 47.1% and 48.1%) and severe OA (43.6%, 41.2% and 44.4%). Prescribing changes were attributed to the CDC guidelines for 58.9% of primary care physicians, 59.1% of rheumatologists, and 73.3% of orthopaedic surgeons. Strong opioids were mostly reserved as third-line treatment. Although treatment effectiveness post-CDC guidelines was not assessed, perceptions of efficacy and quality of life with opioids significantly differed across specialties, whereas perceptions of safety, convenience/acceptability and costs did not. Physicians generally agreed on the barriers to opioid prescribing, with fear of addiction and drug abuse being the most important. Across specialties, physicians reported decreased opioid prescribing for OA, irrespective of OA severity, and in most cases attributed changes in prescribing to the CDC guideline.

A Two-Step, Trajectory-Focused, Analytics Approach to Attempt Prediction of Analgesic Response in Patients with Moderate-to-Severe Osteoarthritis

INTRODUCTION

We sought to predict analgesic response to daily oral nonsteroidal anti-inflammatory drugs (NSAIDs) or subcutaneous tanezumab 2.5 mg (every 8 weeks) at week 16 in patients with moderate-to-severe osteoarthritis, based on initial treatment response over 8 weeks.

METHODS

Data were derived from three randomized controlled trials of osteoarthritis. A two-step, trajectory-focused, analytics approach was used to predict patients as responders or non-responders at week 16. Step 1 identified patients using a data-element combination method (based on pain score at baseline, pain score at week 8, pain score monotonicity at week 8, pain score path length at week 8, and body site [knee or hip]). Patients who could not be identified in step 1 were predicted in step 2 using a k-nearest neighbor method based on pain score and pain response level at week 8.

RESULTS

Our approach predicted response with high accuracy in NSAID-treated (83.2-90.2%, n = 931) and tanezumab-treated (84.6-91.0%, n = 1430) patients regardless of the efficacy measure used to assess pain, or the threshold used to define response (20%, 30%, or 50% improvement from baseline). Accuracy remained high using 50% or 20% response thresholds, with 50% and 20% yielding generally slightly better negative and positive predictive value, respectively, relative to 30%. Accuracy was slightly better in patients aged ≥ 65 years relative to younger patients across most efficacy measure/response threshold combinations.

CONCLUSIONS

Analyzing initial 8-week analgesic responses using a two-step, trajectory-based approach can predict future response in patients with moderate-to-severe osteoarthritis treated with NSAIDs or 2.5 mg tanezumab. These findings demonstrate that prediction of treatment response based on a single dose of a novel therapeutic is possible and that predicting future outcomes based on initial response offers a way to potentially advance the approach to clinical management of patients with osteoarthritis.

CLINICALTRIALS

GOV IDENTIFIERS

NCT02528188, NCT02709486, NCT02697773.

Characterizing 16-Week Responder Profiles Using Group-Based Trajectory Modeling in Over 4300 Clinical Trial Participants Receiving Pharmaceutical Treatment for Moderate to Severe Osteoarthritis

INTRODUCTION

We sought to identify and characterize distinct responder profiles among osteoarthritis (OA) subjects treated with tanezumab, nonsteroidal anti-inflammatory drugs (NSAIDs), or placebo.

METHODS

Subject-level data were derived from three randomized, double-blind, placebo- or NSAID-controlled trials of tanezumab in subjects with moderate-to-severe OA. Subjects received subcutaneous tanezumab (2.5 mg, n = 1527; 5 mg, n = 1279) every 8 weeks, oral NSAIDs (n = 994) daily, or placebo (n = 513). Group-based trajectory modeling (GBTM, an application of finite mixture statistical modeling that uses response trajectory to identify and summarize complex patterns in longitudinal data) was used to identify subgroups of subjects following similar patterns of response in each treatment arm, based on daily pain intensity scores from baseline through Week 16. We then examined whether subject-related variables were associated with any of the subgroups using multinomial logistic regression.

RESULTS

A three-subgroup/four-inflection point trajectory model was selected based on clinical and statistical considerations. The subgroups were high responders (substantial pain improvement and a large majority of members achieved ≥ 30% improvement before Week 16), medium responders (gradual pain improvement and a majority of members achieved ≥ 30% improvement by Week 16), and non-responders (little to no pain improvement over 16 weeks). Across all treatments, fluctuation in pain intensity in the week prior to treatment was consistently associated with treatment response. Other variables were positively (age, body mass index, days of rescue medication use) or negatively (severity of disease based on Kellgren-Lawrence grading) associated with response but effects were small and/or varied across treatments.

CONCLUSIONS

Across all treatments, GBTM identified three subgroups of subjects that were characterized by extent of treatment response (high, medium, and non-responders). Similar analyses (e.g., grouping of subjects based on response trajectory and identification of subgroup-related variables) in other studies of OA could inform clinical trial design and/or treatment approaches. (NCT02697773; NCT02709486; NCT02528188).

Clinical Meaningfulness of Response to Tanezumab in Patients with Chronic Low Back Pain: Analysis From a 56-Week, Randomized, Placebo- and Tramadol-Controlled, Phase 3 Trial

INTRODUCTION

A recent phase 3, randomized, placebo- and tramadol-controlled trial (56-week treatment/24-week safety follow-up) demonstrated efficacy of tanezumab 10 mg in patients with chronic low back pain (CLBP) and a history of inadequate response to standard-of-care analgesics. Here, we report on the clinical meaningfulness of treatment response in this study, focused on secondary measures of pain, interference with daily functions, overall disease status, and satisfaction with treatment.

METHODS

Patients received placebo (up to week 16; n = 406), subcutaneously administered (SC) tanezumab 5 mg (every 8 weeks; n = 407), SC tanezumab 10 mg (every 8 weeks; n = 407), or orally administered tramadol prolonged-release (100-300 mg/day; n = 605) for 56 weeks. Patient's global assessment of low back pain (PGA-LBP), Brief Pain Inventory-short form (BPI-sf), Treatment Satisfaction Questionnaire for Medication (TSQM), and modified Patient-Reported Treatment Impact (mPRTI) were assessed at weeks 16 and 56.

RESULTS

At week 16, significant (p < 0.05) improvements over placebo were evident with tanezumab for the PGA-LBP (10 mg) and most BPI-sf (both doses), TSQM (both doses), and mPRTI (both doses) items assessed. Improvements over baseline persisted for the PGA-LBP and BPI-sf at week 56. However, the magnitude of improvements was modestly lower at week 56 relative to week 16. Tramadol did not improve PGA-LBP or BPI-sf scores versus placebo at week 16. Most differences between tanezumab and tramadol at week 56 did not reach the level of statistical significance for all endpoints.

CONCLUSIONS

The totality of the evidence as captured by measures of pain, interference with daily function, patient overall assessment of disease status, and satisfaction with treatment demonstrates the clinically meaningful benefit of tanezumab for some patients with CLBP compared with placebo.

CLINICALTRIALS

gov: NCT02528253.

WOMAC Meaningful Within-patient Change: Results From 3 Studies of Tanezumab in Patients With Moderate-to-severe Osteoarthritis of the Hip or Knee

OBJECTIVE

To define meaningful within-patient change (MWPC) in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

METHODS

Data were analyzed separately from 3 phase III clinical trials (ClinicalTrials.gov: NCT02697773, NCT02709486, NCT02528188) of tanezumab, a novel treatment intended for the relief of signs and symptoms of moderate-to-severe osteoarthritis (OA), administered subcutaneously every 8 weeks. Patients with moderate-to-severe OA of the hip or knee completed the WOMAC and patient global assessment of OA (PGA-OA) at regular timepoints. A repeated measures longitudinal model with change in WOMAC Pain, Physical Function, or Stiffness domain score as the outcome and change in PGA-OA as the anchor was used to establish MWPC for WOMAC domains.

RESULTS

In the 3 studies, there were 688, 844, and 2948 subjects available for analyses, respectively. Analysis showed that a linear relationship between changes in WOMAC domains and changes in PGA-OA was supported and justified. Moreover, the relationships between these changes were very similar for 2 trials and close for the third. The estimated MWPC for the 3 WOMAC domains were from 0.84-1.16 (0-10 numerical rating scale) and from 12.50-16.23%, depending on study and domain, that corresponded to a 1-category change on PGA-OA. For a 2-category change those values were from 1.68-2.31 and from 25.01-32.46%, respectively.

CONCLUSION

These results establish MWPCs for WOMAC domains, at the individual patient level, for patients with moderate-to-severe OA of the hip or knee. [ClinicalTrials.gov: NCT02697773, NCT02709486, and NCT02528188].

Factors associated with physician-reported treatment status of patients with osteoarthritis pain

BACKGROUND

Osteoarthritis (OA) is typically associated with pain, but many patients are not treated.

METHODS

This point in time study explored factors associated with treatment status, using logistic regression of data from the Adelphi OA Disease Specific Programme conducted in the United States. Patients' treatment status was based on physician-reported, current: 1) prescription medication for OA vs. none; and 2) physician treatment (prescription medication and/or recommendation for specified nonpharmacologic treatment for OA [physical or occupational therapy, acupuncture, transcutaneous electrical nerve stimulation, or cognitive behavior therapy/psychotherapy]) vs. self-management (no prescription medication or specified nonpharmacologic treatment).

RESULTS

The 841 patients (including 57.0% knee OA, 31.9% hip OA) reported mild (45.4%) or moderate or severe (54.6%) average pain intensity over the last week. The majority were prescribed medication and/or recommended specified nonpharmacologic treatment; 218 were not prescription-medicated and 122 were self-managed. Bivariate analyses showed less severe patient-reported pain intensity and physician-rated OA severity, fewer joints affected by OA, lower proportion of joints affected by knee OA, better health status, lower body mass index, and lower ratings for cardiovascular and gastrointestinal risks, for those not prescribed medication (vs. prescription-medicated). Multivariate analyses confirmed factors significantly (p < 0.05) associated with prescription medication included (odds ratio): physician-rated current moderate OA severity (vs. mild, 2.03), patient-reported moderate OA severity 6 months ago (vs. mild, 1.71), knee OA (vs. not, 1.81), physician-recommended (0.28) and patient-reported (0.43) over-the-counter medication use (vs. not), prior surgery for OA (vs. not, 0.37); uncertain income was also significant. Factors significantly (p < 0.05) associated with physician treatment included (odds ratio): physician-recommended nonpharmacologic therapy requiring no/minimal medical supervision (vs. not, 2.21), physician-rated current moderate OA severity (vs. mild, 2.04), patient-reported over-the-counter medication use (vs. not, 0.26); uncertain time since diagnosis was also significant. Patient-reported pain intensity and most demographic factors were not significant in either model.

CONCLUSIONS

Approximately 1 in 4 patients were not prescribed medication and 1 in 7 were self-managed, although many were using over-the-counter medications or nonpharmacologic therapies requiring no/minimal medical supervision. Multiple factors were significantly associated with treatment status, including OA severity and over-the-counter medication, but not pain intensity or most demographics.

Validating a biosignature-predicting placebo pill response in chronic pain in the settings of a randomized controlled trial

ABSTRACT

The objective of this study is to validate a placebo pill response predictive model-a biosignature-that classifies chronic pain patients into placebo responders (predicted-PTxResp) and nonresponders (predicted-PTxNonR) and test whether it can dissociate placebo and active treatment responses. The model, based on psychological and brain functional connectivity, was derived in our previous study and blindly applied to current trial participants. Ninety-four chronic low back pain (CLBP) patients were classified into predicted-PTxResp or predicted-PTxNonR and randomized into no treatment, placebo treatment, or naproxen treatment. To monitor analgesia, back pain intensity was collected twice a day: 3 weeks baseline, 6 weeks of treatment, and 3 weeks of washout. Eighty-nine CLBP patients were included in the intent-to-treat analyses and 77 CLBP patients in the per-protocol analyses. Both analyses showed similar results. At the group level, the predictive model performed remarkably well, dissociating the separate effect sizes of pure placebo response and pure active treatment response and demonstrating that these effects interacted additively. Pain relief was about 15% stronger in the predicted-PTxResp compared with the predicted-PTxNonR receiving either placebo or naproxen, and the predicted-PTxNonR successfully isolated the active drug effect. At a single subject level, the biosignature better predicted placebo nonresponders, with poor accuracy. One component of the biosignature (dorsolateral prefrontal cortex-precentral gyrus functional connectivity) could be generalized across 3 placebo studies and in 2 different cohorts-CLBP and osteoarthritis pain patients. This study shows that a biosignature can predict placebo response at a group level in the setting of a randomized controlled trial.

Durability and delayed treatment effects of zoledronic acid on bone loss after spinal cord injury: a randomized, controlled trial

A single infusion of zoledronic acid (ZOL) after acute spinal cord injury (SCI) attenuates bone loss at the hip (proximal femur) and knee (distal femur and proximal tibia) for at least 6 months. The objective of this study was to examine the effects of timing and frequency of ZOL over 2 years. In this double-blind, placebo-controlled trial, we randomized 60 individuals with acute SCI (<120 days of injury) to receive either ZOL 5-mg infusion (n = 30) or placebo (n = 30). After 12 months, groups were again randomized to receive ZOL or placebo, resulting in four treatment groups for year 2: (i) ZOL both years; (ii) ZOL year 1, placebo year 2; (iii) placebo year 1, ZOL year 2; and (iv) placebo both years. Our primary outcome was bone loss at 12 months; compared to placebo, a single infusion of ZOL attenuated bone loss at the proximal femur, where median changes relative to baseline were -1.7% to -2.2% for ZOL versus -11.3% to -12.8% for placebo (p < 0.001). Similarly, the distal femur and proximal tibia showed changes of -4.7% to -9.6% for ZOL versus -8.9% to -23.0% for placebo (p ≤ 0.042). After 24 months, differences were significant at the proximal femur only (-3.2% to -6.0% for ZOL vs. -16.8% to -21.8% for placebo; p ≤ 0.018). Although not statistically significant, median bone density losses suggested some benefit from two annual infusions compared to a single baseline infusion, as well as from a single infusion 12 months after baseline compared to 2 years of placebo; therefore, further investigation in the 12-month to 24-month treatment window is warranted. No unanticipated adverse events associated with drug treatment were observed. In summary, ZOL 5-mg infusion after acute SCI was well-tolerated and may provide an effective therapeutic approach to prevent bone loss in the first few years following SCI. © 2021 American Society for Bone and Mineral Research (ASBMR).

Long-Term Safety and Efficacy of Subcutaneous Tanezumab Versus Nonsteroidal Antiinflammatory Drugs for Hip or Knee Osteoarthritis: A Randomized Trial

OBJECTIVE

To assess the long-term safety and 16-week efficacy of subcutaneous tanezumab in patients with hip or knee osteoarthritis (OA).

METHODS

This was a phase III randomized, double-blind, active treatment-controlled (using nonsteroidal antiinflammatory drugs [NSAIDs] as the active treatment control) safety trial of tanezumab (56-week treatment/24-week posttreatment follow-up) in adults who were receiving stable-dose NSAID therapy at the time of screening and who had Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and physical function scores of ≥5; patient global assessment (PtGA) of OA of fair, poor, or very poor; history of inadequate pain relief with standard analgesics; and no history or radiographic evidence of prespecified bone/joint conditions beyond OA. Patients received oral naproxen, celecoxib, or diclofenac twice daily (NSAID group; n = 996) or tanezumab 2.5 mg (n = 1,002) or 5 mg (n = 998) subcutaneously every 8 weeks. Coprimary efficacy end points at week 16 were changes in WOMAC pain and physical function scores and changes in PtGA. The primary joint safety end point over 80 weeks comprised adjudicated rapidly progressive OA type 1 or 2, primary osteonecrosis, subchondral insufficiency fracture, or pathologic fracture. Mean values, least squares mean values, and least squares mean differences between groups (with 95% confidence intervals [95% CIs]) were calculated.

RESULTS

Of 3,021 randomized patients, 2,996 received ≥1 treatment dose. Adverse events (AEs) were similar between patients treated with tanezumab 2.5 mg and those treated with NSAIDs, and were more prevalent in those treated with tanezumab 5 mg. Composite joint safety events were significantly more prevalent with tanezumab 2.5 mg and tanezumab 5 mg than with NSAIDs (observation time-adjusted rate/1,000 patient-years 38.3 [95% CI 28.0, 52.5] and 71.5 [95% CI 56.7, 90.2], respectively, versus 14.8 [95% CI 8.9, 24.6]; P = 0.001 for tanezumab 2.5 mg versus NSAIDs; P < 0.001 for tanezumab 5 mg versus NSAIDs). Tanezumab 5 mg significantly improved pain and physical function but did not improve PtGA at week 16 when compared to NSAIDs; corresponding differences between the tanezumab 2.5 mg and NSAID groups were not statistically significant.

CONCLUSION

In patients previously receiving a stable dose of NSAIDs, tanezumab administered subcutaneously resulted in more joint safety events than continued NSAIDs, with differences being dose dependent. Pain and physical function improved with both doses of tanezumab compared to NSAIDs, reaching statistical significance with tanezumab 5 mg at 16 weeks.

General Safety and Tolerability of Subcutaneous Tanezumab for Osteoarthritis: A Pooled Analysis of 3 Randomized, Placebo-Controlled Trials

Objective

This pooled analysis of 3 randomized, placebo‐controlled trials (16–24 week treatment and 8–24 week follow‐up) assessed safety of subcutaneous tanezumab (2.5–10 mg every 8 weeks) in 1,840 patients with hip or knee osteoarthritis.

Methods

Overall treatment‐emergent adverse events (TEAEs) and TEAEs of abnormal peripheral sensation (APS) were prospectively assessed in 3 trials. Joint safety events (primary osteonecrosis, rapidly progressive osteoarthritis [RPOA], subchondral insufficiency fracture, and pathologic fracture; adjudicated by an independent expert committee) and TEAEs potentially associated with sympathetic neuropathy were prospectively assessed in 2 trials.

Results

During the treatment period, overall TEAE rates were 51.7% for placebo and 39.5–54.8% for tanezumab 2.5–10 mg; treatment discontinuation rates were 2.0% for placebo and 0–1.3% for tanezumab. Rates of composite joint safety events (predominantly RPOA type 1) over the treatment plus follow‐up period were 0% for placebo and 0.5–3.2% for tanezumab 2.5–5 mg (5 mg was statistically greater than placebo); total joint replacement rates with tanezumab (5.9–7.0%) were not significantly different from placebo (4.5%). Rates of TEAEs of APS (predominantly paresthesia and hypoesthesia) were 2.2% for placebo and 3.2–12.8% for tanezumab 2.5–10 mg. Rates of TEAEs potentially associated with sympathetic neuropathy (predominantly bradycardia and orthostatic hypotension) were 0.8% for placebo and 0.5–2.8% for tanezumab 2.5–5 mg (exposure‐adjusted rates were not significantly different from placebo).

Conclusion

Tanezumab was generally well tolerated. TEAEs of APS (mostly mild and transient) and joint safety events were infrequent but more common with tanezumab than placebo. A tanezumab dose of 2.5 mg demonstrated a more favorable safety profile than higher doses.

Hippocampus shape deformation: a potential diagnostic biomarker for chronic back pain in women

ABSTRACT

Sex differences in the quality and prevalence of chronic pain are manifold, with women generally presenting higher incidence and severity. Uncovering chronic pain-related sex differences inform neural mechanisms and may lead to novel treatment routes. In a multicenter morphological study (total n = 374), we investigated whether the shape of subcortical regions would reflect sex differences in back pain. Given the hormone-dependent functions of the hippocampus, and its role in the transition to chronic pain, this region constituted our primary candidate. We found that the anterior part of the left hippocampus (alHP) presented outer deformation in women with chronic back pain (CBP), identified in CBP in the United States (n = 77 women vs n = 78 men) and validated in a Chinese data set (n = 29 women vs n = 58 men with CBP, in contrast to n = 53 female and n = 43 male healthy controls). Next, we examined this region in subacute back pain who persisted with back pain a year later (SBPp; n = 18 women vs n = 18 men) and in a subgroup with persistent back pain for 3 years. Weeks after onset of back pain, there was no deformation within alHP, but at 1 and 3 years women exhibited a trend for outer deformation. The alHP partly overlapped with the subiculum and entorhinal cortex, whose functional connectivity, in healthy subjects, was associated with emotional and episodic memory related terms (Neurosynth, reverse inference). These findings suggest that in women the alHP undergoes anatomical changes with pain persistence, highlighting sexually dimorphic involvement of emotional and episodic memory-related circuitry with chronic pain.

Psychosocial, Functional, and Emotional Correlates of Long-Term Opioid Use in Patients with Chronic Back Pain: A Cross-Sectional Case-Control Study

INTRODUCTION

The opiate epidemic has severe medical and social consequences. Opioids are commonly prescribed in patients with chronic pain, and are a main contributor to the opiate epidemic. The adverse effects of long-term opioid usage have been studied primarily in dependence/addiction disorders, but not in chronic pain. Here, we examine the added iatrogenic effects, psychology, and brain morphology of long-term opioid use in matched patients with chronic pain with and without opioid use (case-controlled design).

METHODS

We compared psychosocial, functional, and psychological measures between patients with chronic back pain (CBP) who were managing their pain with or without opioids, thereby controlling for the effect of pain on these outcomes. In addition, we investigated brain morphological differences associated with long-term opioid usage. We recruited 58 patients with CBP, 29 of them on long-term opioids and 29 who did not use opioids, and who were matched in terms of age, sex, pain intensity, and pain duration. Questionnaires were used to assess pain quality, pain psychology, negative and positive emotions, physical, cognitive, sensory, and motor functions, quality of life, and personality traits.

RESULTS

Patients with CBP on opioids displayed more negative emotion, poorer physical function, and more pain interference (p < 0.001), whereas there were no statistical differences in cognitive and motor functions and personality traits. Voxel-based morphometry using structural brain imaging data identified decreased gray matter density of the dorsal paracingulate cortex (family-wise error-corrected p < 0.05) in patients with opioids, which was associated with negative emotion (p = 0.03). Finally, a volumetric analysis of hippocampal subfields identified lower volume of the left presubiculum in patients on opioids (p < 0.001).

CONCLUSION

Long-term opioid use in chronic pain is associated with adverse negative emotion and disabilities, as well as decreased gray matter volumes of specific brain regions.

Dominant and nondominant distal radius microstructure: Predictors of asymmetry and effects of a unilateral mechanical loading intervention

Most information about distal radius microstructure is based on the non-dominant forearm, with little known about the factors that contribute to bilateral asymmetries in the general population, or what factors may influence bilateral changes over time. Here, we analyzed bilateral high resolution peripheral quantitative computed tomography (HRpQCT) data collected over a 12-month period as part of a clinical trial that prescribed a well-controlled, compressive loading task to the nondominant forearm. Baseline data from 102 women age 21–40, and longitudinal data from 66 women who completed the 12-month trial, were examined to determine factors responsible for side-to-side asymmetries in bone structure and change in structure over time. Cross-sectionally, the dominant radius had 2.4%–2.7% larger cross-sectional area, trabecular area, and bone mineral content than the nondominant radius, but no other differences were noted. Those who more strongly favored their dominant arm had significantly more, thinner, closely spaced trabecular struts in their dominant versus nondominant radius. Individuals assigned to a loading intervention had significant bilateral gains in total bone mineral density (2.0% and 1.2% in the nondominant versus dominant sides), and unilateral gains in the nondominant (loaded) cortical area (3.1%), thickness (3.0%), bone mineral density (1.7%) and inner trabecular density (1.3%). Each of these gains were significantly predicted by loading dose, a metric that included bone strain, number of cycles, and strain rate. Within individuals, change was negatively associated with age, meaning that women closer to age 40 experienced less of a gain in bone versus those closer to age 21. We believe that dominant/nondominant asymmetries in bone structure reflect differences in habitual loads during growth and past ability to adapt, while response to loading reflects current individual physiologic capacity to adapt.

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We examined relationships between physical activity, handedness, demographics, and asymmetries in distal radius structure.

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Trabecular and cross-sectional area were 2.4-2.7% larger in the dominant side.

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We examined factors that predicted 12-month change after a unilateral loading intervention on the nondominant side.

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The intervention caused unilateral (nondominant) increases in most variables, which scaled with loading dose.

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The results also suggest that greater dietary calcium is associated with endosteal bone apposition following loading.

Reorganization of functional brain network architecture in chronic osteoarthritis pain

Osteoarthritis (OA) manifests with chronic pain, motor impairment, and proprioceptive changes. However, the role of the brain in the disease is largely unknown. Here, we studied brain networks using the mathematical properties of graphs in a large sample of knee and hip OA (KOA, n = 91; HOA, n = 23) patients. We used a robust validation strategy by subdividing the KOA data into discovery and testing groups and tested the generalizability of our findings in HOA. Despite brain global topological properties being conserved in OA, we show there is a network wide pattern of reorganization that can be captured at the subject‐level by a single measure, the hub disruption index. We localized reorganization patterns and uncovered a shift in the hierarchy of network hubs in OA: primary sensory and motor regions and parahippocampal gyrus behave as hubs and insular cortex loses its central placement. At an intermediate level of network structure, frontoparietal and cingulo‐opercular modules showed preferential reorganization. We examined the association between network properties and clinical correlates: global disruption indices and isolated degree properties did not reflect clinical parameters; however, by modeling whole brain nodal degree properties, we identified a distributed set of regions that reliably predicted pain intensity in KOA and generalized to hip OA. Together, our findings reveal that while conserving global topological properties, brain network architecture reorganizes in OA, at both global and local scale. Network connectivity related to OA pain intensity is dissociated from the major hub disruptions, challenging the extent of dependence of OA pain on nociceptive signaling.

Bone Adaptation in Adult Women Is Related to Loading Dose: A 12-Month Randomized Controlled Trial

Although strong evidence exists that certain activities can increase bone density and structure in people, it is unclear what specific mechanical factors govern the response. This is important because understanding the effect of mechanical signals on bone could contribute to more effective osteoporosis prevention methods and efficient clinical trial design. The degree to which strain rate and magnitude govern bone adaptation in humans has never been prospectively tested. Here, we studied the effects of a voluntary upper extremity compressive loading task in healthy adult women during a 12-month prospective period. A total of 102 women age 21 to 40 years participated in one of two experiments: (i) low (n = 21) and high (n = 24) strain magnitude; or (ii) low (n = 21) and high (n = 20) strain rate. Control (n = 16) no intervention. Strains were assigned using subject-specific finite element models. Load cycles were recorded digitally. The primary outcome was change in ultradistal radius integral bone mineral content (iBMC), assessed with QCT. Interim time points and secondary outcomes were assessed with high resolution pQCT (HRpQCT) at the distal radius. Sixty-six participants completed the intervention, and interim data were analyzed for 77 participants. Likely related to improved compliance and higher received loading dose, both the low-strain rate and high-strain rate groups had significant 12-month increases to ultradistal iBMC (change in control: -1.3 ± 2.7%, low strain rate: 2.7 ± 2.1%, high strain rate: 3.4 ± 2.2%), total iBMC, and other measures. "Loading dose" was positively related to 12-month change in ultradistal iBMC, and interim changes to total BMD, cortical thickness, and inner trabecular BMD. Participants who gained the most bone completed, on average, 128 loading bouts of (mean strain) 575 με at 1878 με/s. We conclude that signals related to strain magnitude, rate, and number of loading bouts contribute to bone adaptation in healthy adult women, but only explain a small amount of variance in bone changes. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

O06 Improvements in pain, function and health status with subcutaneous tanezumab compared with placebo in patients with OA: pooled analysis of two randomized controlled trials

Background

Osteoarthritis (OA) causes pain, disability and impaired quality of life. Tanezumab, a monoclonal antibody against nerve growth factor, is in development for the management of OA pain. Two randomised, placebo-controlled studies with a primary aim of assessing the efficacy and safety of subcutaneously administered tanezumab were recently completed as part of a phase 3 OA programme, and the data reported, separately. Here we report pooled analyses of secondary efficacy outcomes from these two trials: Outcome Measures in Rheumatology - Osteoarthritis Research Society International (OMERACT-OARSI) treatment response and EuroQol 5 Dimension (EQ-5D-5L) questionnaire.

Methods

Both studies enrolled patients with moderate-to-severe OA of the hip or knee, for whom standard care was inadequate or unsuitable. In study one (NCT02709486) with primary endpoint at Week 24, patients received three doses of placebo, tanezumab 2.5 mg or tanezumab 5 mg (at baseline/Week 8/Week 16). Study two was a dose-titration study (NCT02697773) with primary endpoint at Week 16, where patients received two doses of: placebo at baseline/Week 8 (pooled with study one placebo group), tanezumab 2.5 mg at baseline/Week 8 (pooled with study one tanezumab 2.5 mg group) or tanezumab 2.5 mg at baseline/tanezumab 5 mg at Week 8 (pooled with study one tanezumab 5 mg group). The current analysis assessed differences between pooled groups in OMERACT-OARSI treatment response, and EQ-5D-5L questionnaire responses and overall utility scores, at Week 16.

Results

A total of 1,545 patients were evaluated. At Week 16 in the pooled analyses, more patients in the tanezumab 2.5 mg (76.0%, 390/513) or tanezumab 5 mg (77.4%, 400/517) groups than the placebo group (64.7%, 332/513) met the criteria for OMERACT-OARSI response (each p &lt; 0.0001 versus placebo). Patients in the pooled placebo, tanezumab 2.5 mg and 5 mg groups, respectively, recorded their baseline pain/discomfort (EQ-5D-5L) as none (1.8%, 1.0%, 0.6%), slight (7.6%, 9.7%, 8.9%), moderate (52.6%, 50.7%, 50.7%), severe (35.1%, 36.3%, 36.4%) or extreme (2.9%, 2.3%, 3.5%). At Week 16, patients recorded their pain/discomfort as none (12.8%, 15.4%, 15.8%), slight (37.3%, 44.3%, 44.8%), moderate (40.6%, 33.9%, 32.0%), severe (8.8%, 6.4%, 6.4%) or extreme (0.4%, 0.0%, 1.0%). Improvements in mobility, self-care, usual activities and anxiety/depression were also seen. At Week 16, the change from baseline in EQ-5D-5L utility score was greater for the pooled tanezumab 2.5 mg group (difference in least squares means [95% confidence interval], 0.03 [0.01, 0.05], p = 0.0083) or tanezumab 5 mg group (0.04 [0.01, 0.06], p = 0.0015) compared with placebo.

Conclusion

Together, pooled analyses from these studies show that significant improvements in the composite measure OMERACT-OARSI response are accompanied by significant improvements in overall health status as assessed by the EQ-5D-5L utility score at Week 16 for tanezumab-treated patients compared with placebo. These studies were sponsored by Pfizer and Eli Lilly and Company.

Disclosures

D. Walsh: Consultancies; consulting fees (non-personal, pecuniary interest) from Pfizer, Lilly, GlaxoSmithKline, AbbVie, Medscape Education, Love Productions. T.J. Schnitzer: Consultancies; TJS has received consulting fees from Pfizer, Lilly, AbbVie, Aptinyx, Genzyme, Regeneron, and Vertex. Grants/research support; TJS has engaged in clinical research for AbbVie, Grünenthal, and Radius. F. Berenbaum: Consultancies; Consulting fees/remuneration from AbbVie, Merck, Regulaxis, 4P Pharma, Bone Therapeutics, Galapagos, Peptinov, Expanscience, Flexion, Janssen, MerckSerono, Novartis, Roche, Gilead, Sanofi, GlaxoSm. S. Howland: Corporate appointments; SH is an employee of Pfizer Ltd. Shareholder/stock ownership; SH holds Pfizer stock options. S. Wilhelm: Corporate appointments; SW is a Lilly employee. Shareholder/stock ownership; SW holds Lilly stock and/or stock options. R. Junor: Corporate appointments; RJ is an employee of Pfizer Ltd. Shareholder/stock ownership; RJ holds Pfizer stock and/or stock options.

Onset and maintenance of efficacy of subcutaneous tanezumab in patients with moderate to severe osteoarthritis of the knee or hip: A 16-week dose-titration study

OBJECTIVE

To examine the onset and maintenance of efficacy of subcutaneous tanezumab for pain relief and functional improvement in difficult-to-treat patients with moderate-to-severe osteoarthritis (OA) in a 16-week dose-titration study (NCT02697773).

METHODS

Patients were randomized to placebo (placebo group) or tanezumab 2.5 mg at baseline and week 8 (tanezumab 2.5 mg group), or tanezumab 2.5 mg at baseline and tanezumab 5 mg at week 8 (tanezumab 2.5/5 mg group). Analyses included change from baseline in average daily index joint pain and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Physical Function, and treatment responses (WOMAC Pain improvement criteria and Outcome Measures in Rheumatology-Osteoarthritis Research Society International [OMERACT-OARSI] criteria).

RESULTS

The 696 patients received placebo (n = 232), tanezumab 2.5 mg (n = 231), or tanezumab 2.5/5 mg (n = 233). Average daily index joint pain was statistically significantly improved within the first week (day 3-5) with tanezumab 2.5 mg compared with placebo. On first post-randomization WOMAC measurement (week 2), both tanezumab groups had statistically significant improvements compared with placebo in WOMAC Pain and Physical Function, and more tanezumab-treated patients achieved treatment response criteria (≥30%, ≥50%, or ≥70% reduction in WOMAC Pain or OMERACT-OARSI response). Efficacy was generally maintained throughout the 16-week treatment period.

CONCLUSION

Subcutaneous tanezumab provided statistically significant improvements compared with placebo in average daily index joint pain within the first week and WOMAC Pain and Physical Function (week 2) that were generally maintained throughout the 16-week treatment period. Tanezumab 5 mg provided only modest additional efficacy over tanezumab 2.5 mg.

Temporal Factors Associated With Opioid Prescriptions for Patients With Pain Conditions in an Urban Emergency Department

IMPORTANCE

Opioid prescriptions for treatment of pain in emergency departments (EDs) are associated with long-term opioid use. The temporal pattern of opioid prescribing in the context of the opioid epidemic remains unknown.

OBJECTIVE

To examine the temporal pattern of opioid prescribing within an ED for varying pain conditions between 2009 and 2018.

DESIGN, SETTING, AND PARTICIPANTS

A population-based, cross-sectional study was conducted at the ED of an urban academic medical center. All patients treated within that ED between January 1, 2009, and December 31, 2018, were included.

MAIN OUTCOMES AND MEASURES

The proportion of patients prescribed an opioid for treatment of pain in the ED temporally by condition, condition type, patient demographics, and physician prescriber.

RESULTS

Between 2009 and 2018, 556 176 patient encounters took place in the ED, with 70 218 unique opioid prescriptions ordered. A total of 316 632 patients (55.9%) were female, 45 070 (42.6%) were of white race, and 43 412 (40.6%) were privately insured; the median age group was 41 to 45 years. Yearly opioid prescriptions decreased by 66.3% (from 16.3 to 5.5 opioids per 100 encounters) between 2013 and 2018, with a yearly adjusted odds ratio (aOR) of 0.808 (95% CI, 0.802-0.814) compared with the prior year. In patients with musculoskeletal pain (back, joint, limb, and neck pain), opioid prescribing decreased by 71.1% (from 36.7 to 10.6 opioids per 100 encounters between 2013 and 2018; aOR, 0.758; 95% CI, 0.744-0.773). In patients with musculoskeletal trauma (fracture, sprain, contusion, and injury), opioid prescribing decreased by 58.0% (from 34.2 to 14.8 opioids per 100 encounters; aOR, 0.811; 95% CI, 0.797-0.824). In patients with nonmusculoskeletal pain (abdominal pain, kidney stone, respiratory distress, and pharyngitis) opioid prescribing decreased by 53.7% (from 20.1 to 9.3 opioids per 100 encounters; aOR, 0.850; 95% CI, 0.834-0.868). Between 2009 and 2018, patients who were black (aOR, 0.760; 95% CI, 0.741-0.779) and those who were Asian (aOR, 0.714; 95% CI, 0.665-0.764) had the lowest odds of receiving an opioid compared with other racial/ethnic groups.

CONCLUSIONS AND RELEVANCE

There was a substantial temporal decrease in the number of opioid prescriptions within this ED during the study period. This decrease was associated with substantial relative reductions in opioid prescribing for treatment of musculoskeletal pain compared with fractures and kidney stones.

The Efficacy, Tolerability, and Joint Safety of Fasinumab in Osteoarthritis Pain: A Phase IIb/III Double-Blind, Placebo-Controlled, Randomized Clinical Trial

Objective

To prospectively assess the efficacy, general safety, and joint safety of fasinumab, an anti–nerve growth factor monoclonal antibody, in osteoarthritis (OA) hip and/or knee pain.

Methods

Patients with moderate‐to‐severe OA pain (knee or hip) and history of inadequate response or intolerance to analgesics were randomized to receive fasinumab (at 1 mg, 3 mg, 6 mg, or 9 mg) or placebo every 4 weeks over 16 weeks and were followed up to week 36. Efficacy end points were the change from baseline to week 16 in the pain and physical function subscale scores of the Western Ontario and McMaster Universities OA Index (WOMAC), and patient global assessment (PGA) of OA. Joints were monitored at scheduled assessments (by plain film radiography and magnetic resonance imaging) during treatment and follow‐up, and if prompted, at the time of active joint symptoms.

Results

Of the 421 patients randomized, 342 completed the 36‐week study. All doses of fasinumab yielded statistically significant and clinically important reductions in pain compared to placebo (least squares mean difference in WOMAC pain subscale scores at week 16 ranging −0.78 to −1.40), without any clear dose dependence. Physical function and PGA scores improved in parallel. Treatment‐emergent adverse event rates were 17% with fasinumab and 10% with placebo, and 4% and 1% of patients, respectively, discontinued treatment. Arthropathies (25 in total, 7% of fasinumab‐treated patients and 1% of placebo‐treated patients) occurred in a dose‐dependent manner, with 2 occurring in patients receiving the lowest dose of fasinumab and 10 in patients receiving the highest dose. Most of the arthropathies (16 of 25) were discovered with scheduled radiographs and not based on symptoms. Destructive arthropathy (in 1 of 337 treated patients) occurred in 1 patient who was receiving 6 mg fasimumab.

Conclusion

Fasinumab provided improvements in OA pain and function, even in those benefitting little from previous analgesics. The observed benefit‐to‐risk relationship favors further clinical development to explore the lowest doses of fasinumab in patients with knee or hip OA.

Uptake of the OMERACT-OARSI Hip and Knee Osteoarthritis Core Outcome Set: Review of Randomized Controlled Trials from 1997 to 2017

OBJECTIVE

To assess the uptake of the OMERACT-OARSI (Outcome Measures in Rheumatology- Osteoarthritis Research Society International) core outcome set (COS) domains in hip and/or knee osteoarthritis (OA) trials.

METHODS

There were 382 trials of hip and/or knee OA identified from the ClinicalTrial.gov registry from 1997 to 2017. Frequency of COS adoption was assessed by year and per 5-yearly phases.

RESULTS

COS adoption decreased from 61% between 1997 and 2001 to 38% between 2012 and 2016. Pain (95%) and physical function (86%) were most consistently adopted. Patient's global assessment (48%) was the principal missing domain.

CONCLUSION

Limited adoption of the COS domains indicates that further consideration to improve uptake is required.

The OMERACT-OARSI Core Domain Set for Measurement in Clinical Trials of Hip and/or Knee Osteoarthritis

OBJECTIVE

To update the 1997 OMERACT-OARSI (Outcome Measures in Rheumatology-Osteoarthritis Research Society International) core domain set for clinical trials in hip and/or knee osteoarthritis (OA).

METHODS

An initial review of the COMET database of core outcome sets (COS) was undertaken to identify all domains reported in previous COS including individuals with hip and/or knee OA. These were presented during 5 patient and health professionals/researcher meetings in 3 continents (Europe, Australasia, North America). A 3-round international Delphi survey was then undertaken among patients, healthcare professionals, researchers, and industry representatives to gain consensus on key domains to be included in a core domain set for hip and/or knee OA. Findings were presented and discussed in small groups at OMERACT 2018, where consensus was obtained in the final plenary.

RESULTS

Four previous COS were identified. Using these, and the patient and health professionals/researcher meetings, 50 potential domains formed the Delphi survey. There were 426 individuals from 25 different countries who contributed to the Delphi exercise. OMERACT 2018 delegates (n = 129) voted on candidate domains. Six domains gained agreement as mandatory to be measured and reported in all hip and/or knee OA clinical trials: pain, physical function, quality of life, and patient's global assessment of the target joint, in addition to the mandated core domain of adverse events including mortality. Joint structure was agreed as mandatory in specific circumstances, i.e., depending on the intervention.

CONCLUSION

The updated core domain set for hip and/or knee OA has been agreed upon. Work will commence to determine which outcome measurement instrument should be recommended to cover each core domain.

Identification of traits and functional connectivity-based neurotraits of chronic pain

Psychological and personality factors, socioeconomic status, and brain properties all contribute to chronic pain but have essentially been studied independently. Here, we administered a broad battery of questionnaires to patients with chronic back pain (CBP) and collected repeated sessions of resting-state functional magnetic resonance imaging (fMRI) brain scans. Clustering and network analyses applied on the questionnaire data revealed four orthogonal dimensions accounting for 56% of the variance and defining chronic pain traits. Two of these traits-Pain-trait and Emote-trait-were associated with back pain characteristics and could be related to distinct distributed functional networks in a cross-validation procedure, identifying neurotraits. These neurotraits showed good reliability across four fMRI sessions acquired over five weeks. Further, traits and neurotraits all related to the income, emphasizing the importance of socioeconomic status within the personality space of chronic pain. Our approach is a first step in providing metrics aimed at unifying the psychology and the neurophysiology of chronic pain applicable across diverse clinical conditions.

Effect of Tanezumab on Joint Pain, Physical Function, and Patient Global Assessment of Osteoarthritis Among Patients With Osteoarthritis of the Hip or Knee: A Randomized Clinical Trial

IMPORTANCE

Patients with osteoarthritis (OA) may remain symptomatic with traditional OA treatments.

OBJECTIVE

To assess 2 subcutaneous tanezumab dosing regimens for OA.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, double-blind, multicenter trial from January 2016 to May 14, 2018 (last patient visit). Patients enrolled were 18 years or older with hip or knee OA, inadequate response to OA analgesics, and no radiographic evidence of prespecified joint safety conditions.

INTERVENTIONS

Patients received by subcutaneous administration either tanezumab, 2.5 mg, at day 1 and week 8 (n = 231); tanezumab, 2.5 mg at day 1 and 5 mg at week 8 (ie, tanezumab, 2.5/5 mg; n = 233); or placebo at day 1 and week 8 (n = 232).

MAIN OUTCOMES AND MEASURES

Co-primary end points were change from baseline to week 16 in Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC) Pain (0-10, no to extreme pain), WOMAC Physical Function (0-10, no to extreme difficulty), and patient global assessment of osteoarthritis (PGA-OA) (1-5, very good to very poor) scores.

RESULTS

Among 698 patients randomized, 696 received 1 or more treatment doses (mean [SD] age, 60.8 [9.6] years; 65.1% women), and 582 (83.6%) completed the trial. From baseline to 16 weeks, mean WOMAC Pain scores decreased from 7.1 to 3.6 in the tanezumab, 2.5 mg, group; 7.3 to 3.6 in the tanezumab, 2.5/5 mg, group; and 7.3 to 4.4 in the placebo group (least squares mean differences [95% CI] vs placebo were -0.60 [-1.07 to -0.13; P = .01] for tanezumab, 2.5 mg, and -0.73 [-1.20 to -0.26; P = .002] for tanezumab, 2.5/5 mg). Mean WOMAC Physical Function scores decreased from 7.2 to 3.7 in the 2.5-mg group, 7.4 to 3.6 in the 2.5/5-mg group, and 7.4 to 4.5 with placebo (differences vs placebo, -0.66 [-1.14 to -0.19; P = .007] for tanezumab, 2.5 mg, and -0.89 [-1.37 to -0.42; P < .001] for tanezumab, 2.5/5 mg). Mean PGA-OA scores decreased from 3.4 to 2.4 in the 2.5-mg group, 3.5 to 2.4 in the 2.5/5-mg group, and 3.5 to 2.7 with placebo (differences vs placebo, -0.22 [-0.39 to -0.05; P = .01] for tanezumab, 2.5 mg, and -0.25 [-0.41 to -0.08; P = .004] for tanezumab, 2.5/5 mg). Rapidly progressive OA occurred only in tanezumab-treated patients (2.5 mg: n = 5, 2.2%; 2.5/5 mg: n = 1, 0.4%). The incidence of total joint replacements was 8 (3.5%), 16 (6.9%), and 4 (1.7%) in the tanezumab, 2.5 mg; tanezumab, 2.5/5 mg; and placebo groups, respectively.

CONCLUSIONS AND RELEVANCE

Among patients with moderate to severe OA of the knee or hip and inadequate response to standard analgesics, tanezumab, compared with placebo, resulted in statistically significant improvements in scores assessing pain and physical function, and in PGA-OA, although the improvements were modest and tanezumab-treated patients had more joint safety events and total joint replacements. Further research is needed to determine the clinical importance of these efficacy and adverse event findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02697773.

Pooled analysis of tanezumab efficacy and safety with subgroup analyses of phase III clinical trials in patients with osteoarthritis pain of the knee or hip

Purpose

A pooled analysis was conducted to evaluate tanezumab efficacy and safety in patients with osteoarthritis (OA), including subgroup analyses of at-risk patients with diabetes, severe OA symptoms, and those aged ≥65 years.

Patients and methods

Data from phase III placebo-controlled clinical trials of patients with moderate-to-severe OA of the knee or hip were pooled to evaluate tanezumab efficacy (four trials) and safety (nine trials). Patients received intravenous tanezumab, tanezumab plus an oral NSAID (naproxen, celecoxib, or diclofenac), active comparator (naproxen, celecoxib, diclofenac, or oxycodone), or placebo. Efficacy assessments included change from baseline to week 16 in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and physical function scores, Patient’s Global Assessment (PGA) of OA, and percentage of patients with ≥30%, ≥50%, ≥70%, and ≥90% improvement in WOMAC pain. Safety assessments included adverse event (AE) documentation and physical and neurologic examinations.

Results

Tanezumab significantly improved all efficacy end points in the overall population. Efficacy in at-risk patient subgroups was similar to the overall population. Incidence of AEs was highest in the tanezumab plus NSAID group and lowest in the placebo group. Incidence of AEs in the tanezumab monotherapy and active comparator groups was similar. Overall incidence of AEs was similar across subgroups. AEs of abnormal peripheral sensation were more frequently reported in tanezumab-treated patients compared with placebo or active comparator. Patients receiving active comparator had a slightly higher incidence of AEs suggestive of postganglionic sympathetic dysfunction.

Conclusion

Tanezumab consistently provided significant improvement of pain, physical function, and PGA in individuals with OA, including patients with diabetes, severe OA symptoms, or aged ≥65 years. No increased safety risk was observed in at-risk patient subgroups.

Trial registration

NCT00733902, NCT00744471, NCT00830063, NCT00863304, NCT00809354, NCT00864097, NCT00863772, NCT01089725, NCT00985621.

Bone fragility after spinal cord injury: reductions in stiffness and bone mineral at the distal femur and proximal tibia as a function of time

Computed tomography and finite element modeling were used to assess bone structure at the knee as a function of time after spinal cord injury. Analyzed regions experienced degradation in stiffness, mineral density, and content. Changes were well described as an exponential decay over time, reaching a steady state 3.5 years after injury.

INTRODUCTION

Spinal cord injury (SCI) is associated with bone fragility and an increased risk of fracture around the knee. The purpose of this study was to investigate bone stiffness and mineral content at the distal femur and proximal tibia, using finite element (FE) and computed tomography (CT) measures. A cross-sectional design was used to compare differences between non-ambulatory individuals with SCI as a function of time after injury (0-50 years).

METHODS

CT scans of the knee were obtained from 101 individuals who experienced an SCI 30 days to 50 years prior to participation. Subject-specific FE models were used to estimate stiffness under axial compression and torsional loading, and CT data was analyzed to assess volumetric bone mineral density (vBMD) and bone mineral content (BMC) for integral, cortical, and trabecular compartments of the epiphyseal, metaphyseal, and diaphyseal regions of the distal femur and proximal tibia.

RESULTS

Bone degradation was well described as an exponential decay over time (R² = 0.33-0.83), reaching steady-state levels within 3.6 years of SCI. Individuals at a steady state had 40 to 85% lower FE-derived bone stiffness and robust decreases in CT mineral measures, compared to individuals who were recently injured (t ≤ 47 days). Temporal and spatial patterns of bone loss were similar between the distal femur and proximal tibia.

CONCLUSIONS

After SCI, individuals experienced rapid and profound reductions in bone stiffness and bone mineral at the knee. FE models predicted similar reductions to axial and torsional stiffness, suggesting that both failure modes may be clinically relevant. Importantly, CT-derived measures of bone mineral alone underpredicted the impacts of SCI, compared to FE-derived measures of stiffness.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01225055, NCT02325414).

CGRP blockade by galcanezumab was not associated with reductions in signs and symptoms of knee osteoarthritis in a randomized clinical trial

OBJECTIVE

This study tested whether galcanezumab, a humanized monoclonal antibody with efficacy against migraine, was superior to placebo for the treatment of mild or moderate osteoarthritis (OA) knee pain.

METHOD

In a multicenter, double-blind, placebo- and celecoxib-controlled trial, patients with moderate to severe OA pain were randomized to placebo; celecoxib 200 mg daily for 16 weeks; or galcanezumab 5, 50, 120, and 300 mg subcutaneously every 4 weeks, twice. The primary outcome was change from baseline at Week 8 in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscore measured by 100 mm visual analog scale (VAS). The trial was considered positive if ≥1 dose of galcanezumab demonstrated ≥95% Bayesian posterior probability of superiority to placebo and ≥50% posterior probability of superiority to placebo by ≥9 mm. A planned interim analysis allowed termination of the study if posterior probability of superiority to placebo by ≥9 mm was ≤5%. Secondary endpoints included WOMAC function subscore and Patient Global Assessment (PGA) of OA. Safety and tolerability were also assessed.

RESULTS

The study was terminated after interim analysis suggested inadequate efficacy. Celecoxib significantly reduced WOMAC pain subscore compared with placebo [-12.0 mm; 95% confidence interval (CI) -23 to -2 mm]. None of the galcanezumab arms demonstrated clinically meaningful improvement (range: 1.5 to -5.0 mm) or met the prespecified success criteria. No improvement in any secondary objective was observed. Galcanezumab was well tolerated by OA patients.

CONCLUSIONS

This study failed to demonstrate sufficient statistical evidence that galcanezumab was efficacious for treating OA knee pain.

STUDY IDENTIFICATION

NCT02192190.

Effects of Teriparatide and Vibration on Bone Mass and Bone Strength in People with Bone Loss and Spinal Cord Injury: A Randomized, Controlled Trial

Spinal cord injury (SCI) is associated with marked bone loss and an increased risk of fracture. We randomized 61 individuals with chronic SCI and low bone mass to receive either teriparatide 20 μg/d plus sham vibration 10 min/d (n = 20), placebo plus vibration 10 min/d (n = 20), or teriparatide 20 μg/d plus vibration 10 min/d (n = 21). Patients were evaluated for 12 months; those who completed were given the opportunity to participate in an open-label extension where all participants (n = 25) received teriparatide 20 μg/d for an additional 12 months and had the optional use of vibration (10 min/d). At the end of the initial 12 months, both groups treated with teriparatide demonstrated a significant increase in areal bone mineral density (aBMD) at the spine (4.8% to 5.5%). The increase in spine aBMD was consistent with a marked response in serum markers of bone metabolism (ie, CTX, P1NP, BSAP), but no treatment effect was observed at the hip. A small but significant increase (2.2% to 4.2%) in computed tomography measurements of cortical bone at the knee was observed in all groups after 12 months; however, the magnitude of response was not different amongst treatment groups and improvements to finite element-predicted bone strength were not observed. Teriparatide treatment after the 12-month extension resulted in further increases to spine aBMD (total increase from baseline 7.1% to 14.4%), which was greater in patients initially randomized to teriparatide. Those initially randomized to teriparatide also demonstrated 4.4% to 6.7% improvements in hip aBMD after the 12-month extension, while all groups displayed increases in cortical bone measurements at the knee. To summarize, teriparatide exhibited skeletal activity in individuals with chronic SCI that was not augmented by vibration stimulation. Without additional confirmatory data, the location-specific responses to teriparatide would not be expected to provide clinical benefit in this population. © 2018 American Society for Bone and Mineral Research.

Efficacy and safety of single-dose onabotulinumtoxinA in the treatment of symptoms of osteoarthritis of the knee: results of a placebo-controlled, double-blind study

OBJECTIVE

To evaluate intraarticular onabotulinumtoxinA 400 U and 200 U in reducing symptoms of knee osteoarthritis (OA) in patients with nociceptive pain.

DESIGN

A multicenter, double-blind, randomized, placebo-controlled study was conducted in adults with knee OA and a painDETECT questionnaire score of ≤12 (indicating nociceptive pain). Patients were randomized to receive intraarticular onabotulinumtoxinA 400 U or 200 U or placebo (saline) in the study knee on a 1:1:2 ratio and were followed-up for 24 weeks posttreatment. The primary efficacy measure was the daily average numeric rating scale pain score for the study knee over 7 days at week 8. Secondary efficacy measures included the Western Ontario and McMaster Universities Osteoarthritis Index pain and physical function scores, the patient global impression of change score and the 7-day average worst pain score.

RESULTS

Of the 176 enrolled patients, 158 completed the study. The daily average pain score was reduced by approximately two points for all treatments (week 8); the reduction was sustained throughout follow-up, with no significant between-group difference between onabotulinumtoxinA and placebo (both doses: 0.22 [95% confidence interval (CI): -0.33, 0.76]; 400 U: 0.42 [95% CI: -0.26, 1.10]; 200 U: -0.03 [95% CI: -0.70, 0.64]). Similar results were found for all secondary efficacy measures. Treatment-related adverse events occurred in 3.4% of the pooled onabotulinumtoxinA group and placebo group; none were serious.

CONCLUSIONS

There were no significant differences between onabotulinumtoxinA and placebo in reducing average pain score at week 8 compared with baseline in patients with knee OA. No safety concerns were identified. CLINICALTRIALS.

GOV IDENTIFIER

NCT02230956.

Inferring distinct mechanisms in the absence of subjective differences: Placebo and centrally acting analgesic underlie unique brain adaptations

Development and maintenance of chronic pain is associated with structural and functional brain reorganization. However, few studies have explored the impact of drug treatments on such changes. The extent to which long-term analgesia is related to brain adaptations and its effects on the reversibility of brain reorganization remain unclear. In a randomized placebo-controlled clinical trial, we contrasted pain relief (3-month treatment period), and anatomical (gray matter density [GMD], assessed by voxel-based morphometry) and functional connectivity (resting state fMRI nodal degree count [DC]) adaptations, in 39 knee osteoarthritis (OA) patients (22 females), randomized to duloxetine (DLX, 60 mg once daily) or placebo. Pain relief was equivalent between treatment types. However, distinct circuitry (GMD and DC) could explain pain relief in each group: up to 85% of variance for placebo analgesia and 49% of variance for DLX analgesia. No behavioral measures (collected at entry into the study) could independently explain observed analgesia. Identified circuitry were outside of nociceptive circuitry and minimally overlapped with OA-abnormal or placebo response predictive brain regions. Mediation analysis revealed that changes in GMD and DC can influence each other across remote brain regions to explain observed analgesia. Therefore, we can conclude that distinct brain mechanisms underlie DLX and placebo analgesia in OA. The results demonstrate that even in the absence of differences in subjective pain relief, pharmacological treatments can be differentiated from placebo based on objective brain biomarkers. This is a crucial step to untangling mechanisms and advancing personalized therapy approaches for chronic pain.

Hippocampal morphology mediates biased memories of chronic pain

Experiences and memories are often mismatched. While multiple studies have investigated psychological underpinnings of recall error with respect to emotional events, the neurobiological mechanisms underlying the divergence between experiences and memories remain relatively unexplored in the domain of chronic pain. Here we examined the discrepancy between experienced chronic low back pain (CBP) intensity (twice daily ratings) and remembered pain intensity (n = 48 subjects) relative to psychometric properties, hippocampus morphology, memory capabilities, and personality traits related to reward. 77% of CBP patients exaggerated remembered pain, which depended on their strongest experienced pain and their most recent mood rating. This bias persisted over nearly 1 year and was related to reward memory bias and loss aversion. Shape displacement of a specific region in the left posterior hippocampus mediated personality effects on pain memory bias, predicted pain memory bias in a validation CBP group (n = 21), and accounted for 55% of the variance of pain memory bias. In two independent groups (n = 20/group), morphology of this region was stable over time and unperturbed by the development of chronic pain. These results imply that a localized hippocampal circuit, and personality traits associated with reward processing, largely determine exaggeration of daily pain experiences in chronic pain patients.

Tanezumab in the treatment of chronic musculoskeletal conditions

INTRODUCTION

The management of pain associated with chronic musculoskeletal conditions represents a significant challenge for the clinician. There remains a need for novel medications that have a significant analgesic benefit and are also safe and well tolerated. Both pre-clinical and clinical data have provided evidence of the role of nerve growth factor (NGF) in a multitude of pain eliciting conditions. Therefore, the development of monoclonal antibodies to NGF for chronic painful musculoskeletal conditions has generated interest. Areas covered: This manuscript is a review that examines both the pharmacological properties and clinical studies of tanezumab, the most widely studied antibody to NGF, for management of osteoarthritis (OA) and low back pain. In addition, the safety and tolerability profile and development history of tanezumab are also discussed. Expert opinion: Most studies provide strong support for the ability of tanezumab to provide clinically meaningful pain relief in individuals with these conditions, with longer-term studies suggesting durability of effect. The adverse event profile appears favorable, assuming the risk mitigation strategies are effective at reducing the incidence of joint-related side effects. Further data are being collected to define the optimal dose and dosing strategy in both OA and chronic low back pain.

A randomized placebo-controlled pilot study of the efficacy and safety of D-cycloserine in people with chronic back pain

BACKGROUND

Few effective pharmacological treatment options exist for chronic back pain, the leading cause of disability in the US, and all are associated with significant adverse effects.

OBJECTIVE

To determine the efficacy and safety of D-cycloserine, a partial agonist to the N-methyl-D-aspartate receptor, in the treatment of chronic low back pain.

METHODS

A total of 41 participants with chronic back pain who met all inclusion and exclusion criteria were enrolled in a double-blind, placebo-controlled randomized pilot trial of D-cycloserine. Treatment was administered orally for six weeks at escalating daily doses of 100 mg, 200 mg, and 400 mg, each for two weeks. The primary outcome measure was back pain intensity using the Numeric Rating Scale (0-10). Secondary measures were back pain-related questionnaires: McGill Pain Questionnaire short form, painDETECT, PANAS, and BDI. The pre-specified analysis was a two-way repeated measures analysis of variance.

RESULTS

A treatment difference was observed between groups treated with D-cycloserine and placebo at six weeks of 1.05 ± 3.1 units on the Numeric Rating Scale, with an effect size of 0.4 and p = 0.14. This trend of better chronic back pain relief with D-cycloserine was also observed in the secondary measures. No safety issues were seen.

CONCLUSION

The difference in mean pain between the D-cycloserine and placebo groups did not reach statistical significance. However, a clinically meaningful effect size in the magnitude of pain relief was observed with a consistent pattern across multiple outcome measures with good safety, supporting further research into the effectiveness of D-cycloserine for chronic back pain.

Brain Connectivity Predicts Placebo Response across Chronic Pain Clinical Trials

Placebo response in the clinical trial setting is poorly understood and alleged to be driven by statistical confounds, and its biological underpinnings are questioned. Here we identified and validated that clinical placebo response is predictable from resting-state functional magnetic-resonance-imaging (fMRI) brain connectivity. This also led to discovering a brain region predicting active drug response and demonstrating the adverse effect of active drug interfering with placebo analgesia. Chronic knee osteoarthritis (OA) pain patients (n = 56) underwent pretreatment brain scans in two clinical trials. Study 1 (n = 17) was a 2-wk single-blinded placebo pill trial. Study 2 (n = 39) was a 3-mo double-blinded randomized trial comparing placebo pill to duloxetine. Study 3, which was conducted in additional knee OA pain patients (n = 42), was observational. fMRI-derived brain connectivity maps in study 1 were contrasted between placebo responders and nonresponders and compared to healthy controls (n = 20). Study 2 validated the primary biomarker and identified a brain region predicting drug response. In both studies, approximately half of the participants exhibited analgesia with placebo treatment. In study 1, right midfrontal gyrus connectivity best identified placebo responders. In study 2, the same measure identified placebo responders (95% correct) and predicted the magnitude of placebo's effectiveness. By subtracting away linearly modeled placebo analgesia from duloxetine response, we uncovered in 6/19 participants a tendency of duloxetine enhancing predicted placebo response, while in another 6/19, we uncovered a tendency for duloxetine to diminish it. Moreover, the approach led to discovering that right parahippocampus gyrus connectivity predicts drug analgesia after correcting for modeled placebo-related analgesia. Our evidence is consistent with clinical placebo response having biological underpinnings and shows that the method can also reveal that active treatment in some patients diminishes modeled placebo-related analgesia. Trial Registration ClinicalTrials.gov NCT02903238 ClinicalTrials.gov NCT01558700.

Efficacy and Safety of Proton-Pump Inhibitors in High-Risk Cardiovascular Subsets of the COGENT Trial

BACKGROUND

Proton-pump inhibitors (PPIs) have been demonstrated to reduce rates of gastrointestinal events in patients requiring dual antiplatelet therapy (DAPT). Data are limited regarding the efficacy and safety of PPIs in high-risk cardiovascular subsets after acute coronary syndrome or percutaneous coronary intervention.

METHODS

All patients enrolled in COGENT (Clopidogrel and the Optimization of Gastrointestinal Events Trial) were initiated on DAPT (with aspirin and clopidogrel) for various indications within the prior 21 days. These post hoc analyses of the COGENT trial evaluated the efficacy and safety of omeprazole compared with placebo in subsets of patients requiring DAPT for the 2 most frequent indications: 1) patients undergoing percutaneous coronary intervention (for any indication) within 14 days of randomization (n = 2676; 71.2%); and 2) patients presenting with acute coronary syndrome managed with or without percutaneous coronary intervention (n = 1573; 41.8%). Unadjusted Cox proportional hazards models were used to estimate effect sizes through final follow-up.

RESULTS

Median follow-up duration was 110 days (interquartile range 55-167). In percutaneous coronary intervention-treated patients, omeprazole significantly reduced rates of composite gastrointestinal events at 180 days (1.2% vs 2.7%; hazard ratio [HR] 0.43; 95% confidence interval [CI], 0.22-0.85; P = .02) without increasing composite cardiovascular events (5.4% vs 6.3%; HR 1.00; 95% CI, 0.67-1.50; P = 1.00). Similarly, omeprazole lowered risk of the primary gastrointestinal endpoint at 180 days in patients presenting with acute coronary syndrome (1.1% vs 2.7%; HR 0.37; 95% CI, 0.13-1.01; P = .05) without a significant excess in cardiovascular events (5.6% vs 4.5%; HR 1.40; 95% CI, 0.77-2.53; P = .27).

CONCLUSIONS

PPI therapy attenuates gastrointestinal bleeding risk without significant excess in major cardiovascular events in high-risk cardiovascular subsets, regardless of indication for DAPT. Future studies will be needed to clarify optimal gastroprotective strategies for higher-intensity and longer durations of DAPT.

Corticolimbic anatomical characteristics predetermine risk for chronic pain

SEE TRACEY DOI101093/BRAIN/AWW147 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Mechanisms of chronic pain remain poorly understood. We tracked brain properties in subacute back pain patients longitudinally for 3 years as they either recovered from or transitioned to chronic pain. Whole-brain comparisons indicated corticolimbic, but not pain-related circuitry, white matter connections predisposed patients to chronic pain. Intra-corticolimbic white matter connectivity analysis identified three segregated communities: dorsal medial prefrontal cortex-amygdala-accumbens, ventral medial prefrontal cortex-amygdala, and orbitofrontal cortex-amygdala-hippocampus. Higher incidence of white matter and functional connections within the dorsal medial prefrontal cortex-amygdala-accumbens circuit, as well as smaller amygdala volume, represented independent risk factors, together accounting for 60% of the variance for pain persistence. Opioid gene polymorphisms and negative mood contributed indirectly through corticolimbic anatomical factors, to risk for chronic pain. Our results imply that persistence of chronic pain is predetermined by corticolimbic neuroanatomical factors.

Proton-Pump Inhibitors Reduce Gastrointestinal Events Regardless of Aspirin Dose in Patients Requiring Dual Antiplatelet Therapy

BACKGROUND

The COGENT (Clopidogrel and the Optimization of Gastrointestinal Events Trial) showed that proton-pump inhibitors (PPIs) safely reduced rates of gastrointestinal (GI) events in patients requiring dual antiplatelet therapy (DAPT). However, utilization of appropriate prophylactic PPI therapy remains suboptimal, especially with low-dose aspirin.

OBJECTIVES

The authors investigated the safety and efficacy of PPI therapy in patients receiving DAPT in low- and high-dose aspirin subsets.

METHODS

Randomized patients with available aspirin dosing information in COGENT (N = 3,752) were divided into "low-dose" (≤ 100 mg) and "high-dose" (>100 mg) aspirin groups. The primary GI and cardiovascular endpoints were composite upper GI events and major adverse cardiac events, respectively. All events were adjudicated by independent, blinded gastroenterologists and cardiologists.

RESULTS

Median duration of follow-up was 110 days. Low-dose aspirin users (n = 2,480; 66.1%) were more likely to be older, female, and have higher rates of peripheral artery disease, prior stroke, and hypertension, whereas high-dose aspirin users (n = 1,272; 33.9%) had higher rates of hyperlipidemia, smoking, a history of percutaneous coronary intervention, and were more than twice as likely to be enrolled from sites within the United States (80.4% vs. 39.8%). High-dose aspirin was associated with similar 180-day Kaplan-Meier estimates of adjudicated composite GI events (1.7% vs. 2.1%; adjusted hazard ratio: 0.88; 95% confidence interval: 0.46 to 1.66) and major adverse cardiac events (4.8% vs. 5.5%; adjusted hazard ratio: 0.73; 95% confidence interval: 0.48 to 1.11) compared with low-dose aspirin. Randomization to PPI therapy reduced 180-day Kaplan-Meier estimates of the primary GI endpoint in low-dose (1.2% vs. 3.1%) and high-dose aspirin subsets (0.9% vs. 2.6%; p for interaction = 0.80), and did not adversely affect the primary cardiovascular endpoint in either group.

CONCLUSIONS

Gastroprotection with PPI therapy should be utilized in appropriately selected patients with coronary artery disease requiring DAPT, even if the patients are on low-dose aspirin. (Clopidogrel and the Optimization of Gastrointestinal Events Trial [COGENT]; NCT00557921).

The Emotional Brain as a Predictor and Amplifier of Chronic Pain

Human neuroimaging studies and complementary animal experiments now identify the gross elements of the brain involved in the chronification of pain. We briefly review these advances in relation to somatic and orofacial persistent pain conditions. First, we emphasize the importance of reverse translational research for understanding chronic pain-that is, the power of deriving hypotheses directly from human brain imaging of clinical conditions that can be invasively and mechanistically studied in animal models. We then review recent findings demonstrating the importance of the emotional brain (i.e., the corticolimbic system) in the modulation of acute pain and in the prediction and amplification of chronic pain, contrasting this evidence with recent findings regarding the role of central sensitization in pain chronification, especially for orofacial pain. We next elaborate on the corticolimbic circuitry and underlying mechanisms that determine the transition to chronic pain. Given this knowledge, we advance a new mechanistic definition of chronic pain and discuss the clinical implications of this new definition as well as novel therapeutic potentials suggested by these advances.

Zoledronic Acid Treatment After Acute Spinal Cord Injury: Results of a Randomized, Placebo-Controlled Pilot Trial

OBJECTIVE

To determine the effect of intravenous zoledronic acid 5 mg on the extent and course of bone loss after spinal cord injury (SCI).

DESIGN

Double-blind, randomized, placebo-controlled parallel-group trial.

SETTING

Acute in-patient, tertiary-care rehabilitation hospital.

PARTICIPANTS

Convenience sample of 17 in-patients with SCI <12 weeks before randomization; American Spinal Injury Association Impairment scale A, B, or C and medically stable. Twelve patients were evaluated at the primary endpoint at 6 months.

METHODS

Patients meeting study criteria were randomly assigned to zoledronic acid 5 mg or matching placebo. Dual x-ray absorptiometry scan and serum for bone markers (type 1 procollagen amino-terminal propeptide, bone-specific alkaline phosphatase, collagen type 1 cross-linked C-telopeptide) were obtained at baseline and after 3 months, 6 months, and the every 6 months for up to 2 years.

MAIN OUTCOME MEASURES

The primary endpoint was change in bone mineral density (BMD) at the total hip after 6 months; secondary endpoints were changes in BMD at other skeletal sites and changes in levels of serum bone markers.

RESULTS

The group treated with zoledronic acid had a smaller decrease in BMD at 6 months at the total hip than the placebo group (right: -2.2 ± 3.4% versus -8.6 ± 3.5%, respectively, P = .03; left: -3.7 ± 1.0% versus -12.3 ± 6.9%, P = .03). Differences in BMD at the femoral neck were similar (right: -5.1 ± 6.5% versus -20.0 ± 6.4%, P = .01; left: -1.1 ± 3.5% versus -11.1 ± 7.4%, P = .02) with larger bone loss and smaller between group differences at the knee. Zoledronic acid resulted in a decrease in serum levels of both formation and resorption markers.

CONCLUSIONS

Zoledronic acid is effective at mitigating bone loss after SCI. Duration of efficacy and activity at different skeletal sites may differ from that observed in able-bodied individuals and needs further study.