Survey criteria for fibromyalgia independently predict increased postoperative opioid consumption after lower-extremity joint arthroplasty: a prospective, observational cohort study

A Standardized Minimal Opioid Prescription Post-Thoracic Surgery Provides Adequate Pain Control

BACKGROUND

Given the national opioid crisis, post-operative analgesia at discharge must be thoughtfully prescribed. Data, specifically related to thoracic procedures, remains scarce. This study assesses adequacy of pain control with standardized and limited opioids after thoracic procedures.

METHODS

A standardized prescription comprised of 15 Hydromorphone tabs, 7 days of Acetaminophen and 3 days of Ibuprofen was provided on discharge to elective thoracic surgery patients. On the first post-operative visit, patients completed a questionnaire regarding the number of Hydromorphones used, use of additional opioids, pain-related limitation to function, and adequacy of pain control.

RESULTS

A total of 122 patients undergoing thoracic surgery procedures were surveyed. Twelve underwent open procedures and were excluded. An additional 6 who used opioids chronically preoperatively were also excluded. The remaining 104 patients were included in the study. Median age was 66 yrs. (17 to 90 yrs.), median length of stay was 2 days (1 to 15). Seventeen (16%) used all prescribed Hydromorphone and 56 (54%) used none, 18 (17%) asked for additional/other opioid, and 14 (13%) felt that their pain significantly limited their function. Nine (9%) felt that their pain was inadequately controlled.

CONCLUSIONS

Pain after thoracic procedures, especially VATS, is adequately controlled with minimal opioid doses (combined with adjuncts) with less than 1 in 5 patients requiring additional prescriptions and very few patients complaining of pain that "significantly limited their function". This study shows that a standardized limited opioid prescription is safe, adequate, and can easily be implemented for the majority of thoracic surgery patients.

Central Sensitivity and Fibromyalgia

Fibromyalgia presents with symptoms of widespread pain, fatigue, sleeping and cognitive disturbances as well as other somatic symptoms. It often overlaps with other conditions termed 'central sensitivity syndromes' such as irritable bowel syndrome, chronic fatigue syndrome and temporomandibular disorder. Central sensitisation, mediated by amplified processing in the central nervous system, has been identified as the key pathogenic mechanism in these disorders. The term 'central sensitivity' can be used to collectively describe the clinical presentation of these disorders. Fibromyalgia is highly prevalent in most rheumatic diseases as well as non-rheumatic chronic diseases and if unrecognised results in high morbidity. It is diagnosed clinically after excluding important differential diagnoses. Diagnostic criteria have been developed as tools to help identify and diagnose fibromyalgia. Such tools can fulfill an important need when managing patients with rheumatic disease and other chronic diseases as a way to identify fibromyalgia and improve patient outcomes. Treatment involves an integrated approach including education, exercise, stress reduction and pharmacological therapies targeting the central nervous system. This approach is suitable for all presentations of central sensitivity and some central sensitivity syndromes have additional treatment options specific to the clinical presentation. This article is protected by copyright. All rights reserved.

Fibromyalgia syndrome - a risk factor for poor outcomes following orthopaedic surgery: A systematic review

BACKGROUND

Fibromyalgia (FM) is a complex syndrome incorporating many features associated with poor outcome in orthopaedic surgery. Aim of the present review was to comprehensively characterize the available evidence on the consequences of pre-existent FM on the outcomes of orthopaedic surgery.

METHODS

We performed a systematic search in MedLine and Web of Science (WOS) to identify studies evaluating the effect of FM on patient-centred outcomes, opioids consumption and postoperative complications.

RESULTS

The search strategy identified 519 records in PubMed and 507 in WOS. A total of 27 articles were deemed eligible for inclusion in qualitative synthesis. Based on quality assessment, 10 studies were rated as good quality, 10 as fair quality and 7 as poor quality. Studies reporting the prevalence of FM in consecutive patients undergoing orthopaedic surgery (n = 19) were included in quantitative synthesis. The pooled prevalence of FM in patients undergoing orthopaedic surgery was 4.1% (95% CI: 2.4-6.8) in those receiving hip or knee surgery, 10.1% (95% CI: 5.7-17.2) in those receiving shoulder or elbow surgery and 21.0% (95% CI: 18.5-23.7) in those receiving spinal surgery. The results of our systematic review consistently report FM as a significant risk factor for less satisfaction, higher pain, worse functional outcome, increased risk for postoperative opioids prescription and higher rate of medical and surgical complications following orthopaedic surgery.

CONCLUSION

Identifying pre-existing FM in patients scheduled for elective orthopaedic surgery may help to better assess the benefit/risk ratio, improve patients' awareness and minimize any discrepancy between expectancy and results.

Variation in perioperative opioid use after total joint arthroplasty

Objective

We studied variation in perioperative opioid use after total joint arthroplasty with respect to patient and procedure characteristics in order to inform initiatives to optimize pain relief.

Methods

We recorded perioperative opioid consumption for a cohort of total joint arthroplasty patients to identify factors underlying variation in perioperative opioid use.

Results

Younger patient age, tobacco use, greater symptoms of depression, private insurance, and knee arthroplasty were associated with increased opioid consumption.

Conclusions

Awareness of the patient characteristics associated with increased perioperative opioid use can help inform implementation of targeted strategies for safe, optimal pain relief and satisfaction.

Characterizing chronic pain phenotypes in multiple sclerosis: a nationwide survey study

ABSTRACT

Chronic pain is highly prevalent in multiple sclerosis (MS). Pain heterogeneity may contribute to poor treatment outcomes. The aim of this study was to characterize pain phenotypes distributions in persons with MS and compare pain phenotypes in terms of pain intensity, frequency of chronic overlapping pain conditions, and use and analgesic effects of different classes of pain medications. Data were collected through a national web-based survey with measures of neuropathic (painDETECT) and nociplastic pain (Fibromyalgia Survey Criteria), chronic overlapping pain conditions, and pain medication use and pain relief. In a sample of N = 842 adults with chronic pain and MS, the largest proportion (41%) showed evidence of nociceptive pain, 27% had mixed neuropathic/nociplastic pain, 23% had nociplastic pain, and 9% had neuropathic pain. Nociplastic pain was associated with significantly higher pain intensity and frequency of chronic overlapping pain conditions. Across all pain types, high frequency of pain medication use along with poor-modest pain relief was reported. Cannabis use for pain was more common, and pain relief ratings were higher among those with nociplastic pain, relative to nociceptive pain. Although NSAID use was highest among those with nociplastic pain (80%), pain relief ratings for NSAIDs were highest among those with nociceptive pain. These findings underscore the need for multidimensional assessment of pain in MS with greater emphasis on the identification of pain phenotype. An improved characterization of pain as a multifaceted condition in MS could inform therapeutic approaches.

Recommendations by the Spanish Society of Rheumatology on Fibromyalgia. Part 1: Diagnosis and Treatment

OBJECTIVE

To prevent the impairment of fibromyalgia patients due to harmful actions in daily clinical practice that are potentially avoidable.

METHODS

A multidisciplinary team identified the main areas of interest and carried out an analysis of scientific evidence and established recommendations based on the evidence and "formal evaluation" or "reasoned judgment" qualitative analysis techniques.

RESULTS

A total of 39 recommendations address diagnosis, unsafe or ineffective treatment interventions and patient and healthcare workers' education. This part I shows the first 27 recommendations on the first 2 areas.

CONCLUSIONS

Establishing a diagnosis improves the patient's coping with the disease and reduces healthcare costs. NSAIDs, strong opioids and benzodiazepines should be avoided due to side effects. There is no good evidence to justify the association of several drugs. There is also no good evidence to recommend any complementary medicine. Surgeries show a greater number of complications and a lower degree of patient satisfaction and therefore should be avoided if the surgical indication is not clearly established.

Insulin Resistance is Associated with Central Pain in Patients with Fibromyalgia

BACKGROUND

Insulin resistance (IR) is a pathological condition in which cells fail to respond normally to insulin. IR has been associated with multiple conditions, including chronic pain. Fibromyalgia (FM) is one of the common generalized chronic painful conditions with an incidence rate affecting 3% to 6% of the population. Substantial interest and investigation into FM continue to generate  many hypotheses.The relationship between IR and FM has not been explored. IR is known to cause abnormalities in the cerebral microvasculature, leading to focal hypoperfusion. IR also has been shown to cause cognitive impairment in FM patients, as in parkinsonism. As demonstrated by advanced imaging methods, similar brain perfusion abnormalities occur in the brain of patients with FM as with IR.

OBJECTIVES

To determine the potential association between FM and IR.

SETTING

Subspecialty pain medicine clinics.

STUDY DESIGN

Observational cross-sectional study.

METHODS

Laboratory data was extracted through a retrospective review of medical records from patients who had met the American College of Rheumatology (ACR) criteria for FM. The Hemoglobin A1c (HbA1c) values from 33 patients with FM were compared with the means of the glycated HbA1c levels of 2 control populations. In addition, established indices of IR [Quantitative Insulin Sensitivity Check Index (QUICKI) and the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)] were calculated in a subgroup of patients in whom the analytes necessary for these calculations were available. To assess for confounding factors, the associations between HbA1c, QUICKI, HOMA-IR, fasting insulin levels, and glucose, after controlling for age, were explored by multiple analyses of variance with relation to gender and ethnicity.

RESULTS

We found an association between IR and FM that was independent of age, gender, and ethnicity. We found that patients with FM belong to a distinct population that can be segregated from the control groups by their HbA1c levels, a surrogate marker of IR. This was demonstrated by analyzing the data after introducing an age correction into a linear regression model. This strategy showed significant differences between patients with FM and control subjects (P < 0.0001 and P  = 0.0002, for 2 separate control populations, respectively). A subgroup analysis using the QUICKI and HOMA-IR showed that all patients with FM in this subgroup (100%) exhibited laboratory abnormalities pointing to IR.

LIMITATIONS

Small observational cross-sectional study. There are also intrinsic limitations that are attributed to cross-sectional studies.

CONCLUSION

The association demonstrated in this study warrant further investigation, including the pursuit of randomized, double-blind clinical trials to determine the effect of improving insulin sensitivity in FM related pain scores. Such studies could unveil a potential pathogenetic relationship between FM, central pain, and IR. Based on these initial findings, we present the hypothesis that IR may underlie pathological mechanisms leading to central pain. If confirmed, this may lead to a paradigm shift in the management of central pain.

Impact of Fibromyalgia Phenotype in Temporomandibular Disorders

BACKGROUND

Mounting evidence suggests that central nervous system amplification, similar to that seen in fibromyalgia (FM), contributes to the pain experience in a subset of patients with temporomandibular disorders (TMD).

METHODS

In this prospective observational study, patients with TMD completed the 2011 FM survey questionnaire, a surrogate measure of "centralized" pain. The influence of centralized pain on TMD pain, dysfunction, and disability was assessed dichotomously by determining the incidence of FM-positive cases in the sample and by using FM survey scores as a continuous measure of "fibromyalgia-ness" ("FM-ness").

RESULTS

The patients meeting criteria for FM diagnosis (17 of 89) had significantly more disease burden on numerous measures. FM-ness was positively associated with pain at rest, negative mood, tenderness to palpation, perceived jaw functional limitation, and pain-related disability, and it was negatively associated with comfortable pain-free jaw opening. The impact of FM-ness on perceived jaw functional limitation and disability was mediated by levels of spontaneous, ongoing pain in the orofacial region. Importantly, this pattern of findings was still present even in those not meeting the criteria for FM diagnosis.

CONCLUSION

Together, these results imply that higher FM-ness increases TMD patient burden by amplifying spontaneous pain and further hampering painless jaw function, even in patients who do not meet criteria for FM diagnosis. These results are highly relevant for the clinical management of TMD, as they imply that targeting the central nervous system in the treatment of patients with TMD with evidence of pain centralization may help ameliorate both pain and jaw dysfunction.

Patient Factors Associated With Opioid Consumption in the Month Following Major Surgery

OBJECTIVE

The aim of this study was to determine preoperative patient characteristics associated with postoperative outpatient opioid use and assess the frequency of postoperative opioid overprescribing.

SUMMARY BACKGROUND DATA

Although characteristics associated with inpatient opioid use have been described, data regarding patient factors associated with opioid use after discharge are lacking. This hampers the development of individualized approaches to postoperative prescribing.

METHODS

We included opioid-naïve patients undergoing hysterectomy, thoracic surgery, and total knee and hip arthroplasty in a single-center prospective observational cohort study. Preoperative phenotyping included self-report measures to assess pain severity, fibromyalgia survey criteria score, pain catastrophizing, depression, anxiety, functional status, fatigue, and sleep disturbance. Our primary outcome measure was self-reported total opioid use in oral morphine equivalents. We constructed multivariable linear-regression models predicting opioids consumed in the first month following surgery.

RESULTS

We enrolled 1181 patients; 1001 had complete primary outcome data and 913 had complete phenotype data. Younger age, non-white race, lack of a college degree, higher anxiety, greater sleep disturbance, heavy alcohol use, current tobacco use, and larger initial opioid prescription size were significantly associated with increased opioid consumption. Median total oral morphine equivalents prescribed was 600 mg (equivalent to one hundred twenty 5-mg hydrocodone pills), whereas median opioid consumption was 188 mg (38 pills).

CONCLUSIONS

In this prospective cohort of opioid-naïve patients undergoing major surgery, we found a number of characteristics associated with greater opioid use in the first month after surgery. Future studies should address the use of non-opioid medications and behavioral therapies in the perioperative period for these higher risk patients.

A Conceptual Model of Biopsychosocial Mechanisms of Transition from Acute to Chronic Postsurgical Pain in Children and Adolescents

Acute and chronic pain are highly prevalent and impactful consequences of surgery across the lifespan, yet a comprehensive conceptual model encompassing biopsychosocial factors underlying acute to chronic pain transition is lacking, particularly in youth. Building on prior chronic postsurgical pain models, we propose a new conceptual model of biopsychosocial mechanisms of transition from acute to chronic postsurgical pain. This review aims to summarize existing research examining key factors underlying acute to chronic postsurgical pain transition in order to guide prevention and intervention efforts aimed at addressing this health issue in children. As pain transitions from acute nociceptive pain to chronic pain, changes in the peripheral and central nervous system contribute to the chronification of pain after surgery. These changes include alterations in sensory pain processing and psychosocial processes (psychological, behavioral, and social components), which promote the development of chronic pain. Patient-related premorbid factors (eg, demographic factors, genetic profile, and medical factors such as premorbid pain) may further modulate these changes. Factors related to acute injury and recovery (eg, surgical and treatment factors), as well as biological response to surgery (eg, epigenetic, inflammatory, and endocrine factors), may also influence this process. Overall, longitudinal studies examining temporal pathways of biopsychosocial processes including both risk and resiliency factors will be essential to identify the mechanisms involved in the transition from acute to chronic pain. Research is also needed to unravel connections between the acute pain experience, opioid exposure, and sensory pain processing during acute to chronic pain transition. Furthermore, future studies should include larger and more diverse samples to more fully explore risk factors in a broader range of pediatric surgeries. The use of conceptual models to guide intervention approaches targeting mechanisms of transition from acute to chronic pain will significantly advance this field and improve outcomes for children and adolescents undergoing surgery.

Preoperative Factors Associated with Remote Postoperative Pain Resolution and Opioid Cessation in a Mixed Surgical Cohort: Post Hoc Analysis of a Perioperative Gabapentin Trial

Background

Preoperative patient-specific risk factors may elucidate the mechanisms leading to the persistence of pain and opioid use after surgery. This study aimed to determine whether similar or discordant preoperative factors were associated with the duration of postoperative pain and opioid use.

Methods

In this post hoc analysis of a randomized, double-blind, placebo-controlled trial of perioperative gabapentin vs active placebo, 410 patients aged 18–75 years, undergoing diverse operations underwent preoperative assessments of pain, opioid use, substance use, and psychosocial variables. After surgery, a modified Brief Pain Inventory was administered over the phone daily up to 3 months, weekly up to 6 months, and monthly up to 2 years after surgery. Pain and opioid cessation were defined as the first of 5 consecutive days of 0 out of 10 pain or no opioid use, respectively.

Results

Overall, 36.1%, 19.8%, and 9.5% of patients continued to report pain, and 9.5%, 2.4%, and 1.7% reported continued opioid use at 3, 6, and 12 months after surgery. Preoperative pain at the future surgical site (every 1-point increase in the Numeric Pain Rating Scale; HR 0.93; 95% CI 0.87–1.00; P=0.034), trait anxiety (every 10-point increase in the Trait Anxiety Inventory; HR 0.79; 95% CI 0.68–0.92; P=0.002), and a history of delayed recovery after injury (HR 0.62; 95% CI 0.40–0.96; P=0.034) were associated with delayed pain cessation. Preoperative opioid use (HR 0.60; 95% CI 0.39–0.92; P=0.020), elevated depressive symptoms (every 5-point increase in the Beck Depression Inventory-II score; HR 0.88; 95% CI 0.80–0.98; P=0.017), and preoperative pain outside of the surgical site (HR 0.94; 95% CI 0.89–1.00; P=0.046) were associated with delayed opioid cessation, while perioperative gabapentin promoted opioid cessation (HR 1.37; 95% CI 1.06–1.77; P=0.016).

Conclusion

Separate risk factors for prolonged post-surgical pain and opioid use indicate that preoperative risk stratification for each outcome may identify patients needing personalized care to augment universal protocols for perioperative pain management and conservative opioid prescribing to improve long-term outcomes.

Common Biological Modulators of Acute Pain: An Overview Within the AAAPT Project (ACTTION-APS-AAPM Acute Pain Taxonomy)

OBJECTIVE

The ACTTION-APS-AAPM Acute Pain Taxonomy (AAAPT) project relies on the identification of modulators to improve characterization and classification of acute pain conditions. In the frame of the AAAPT effort, this paper presents an overview of common biological modulators of acute pain.

METHODS

Nonsystematic overview.

RESULTS

Females may experience more acute pain than males, but the clinical significance may be modest. Increasing age is associated with decreasing analgesic requirement and decreasing pain intensity after surgery and with higher risk of acute low back pain. Racial and ethnic minorities have worse pain, function, and perceived well-being. Patients with preexisting chronic pain and opioid use are at higher risk of severe acute pain and high opioid consumption. The OPRM1 gene A118G polymorphism is associated with pain severity and opioid consumption, with modest quantitative impact. Most studies have found positive associations between pain sensitivity and intensity of acute clinical pain. However, the strength of the association is unclear. Surgical techniques, approaches, and complications influence postoperative pain.

CONCLUSIONS

Sex, age, race, ethnicity, preexisting chronic pain and opioid use, surgical approaches, genetic factors, and pain sensitivity are biological modulators of acute pain. Large studies with multisite replication will quantify accurately the association between modulators and acute pain and establish the value of modulators for characterization and classification of acute pain conditions, as well as their ability to identify patients at risk of uncontrolled pain. The development and validation of quick, bed-side pain sensitivity tests would allow their implementation as clinical screening tools. Acute nonsurgical pain requires more investigation.

Cannabinoid use among Americans with MS: Current trends and gaps in knowledge

Background

Up-to-date information regarding the scope and impact of cannabinoid use among persons with MS (PwMS) is necessary to guide clinical practice and cannabinoid research.

Objectives

To assess utilization patterns and perceived impact of cannabinoid use among a national cohort of PwMS.

Methods

Data collected were part of a nationwide survey to characterize pain in PwMS. Items included questions about current/recent cannabinoid use, reasons for use, preferred THC/CBD formulations, and perceived benefits/side effects. PROMIS short-forms assessed symptom severity. Pain phenotype was assessed with the painDETECT questionnaire and FMSurvey Criteria Questionnaires.

Results

Among n = 1,027 respondents, 42% endorsed recent cannabinoid use, of which 18% endorsed healthcare provider guidance regarding use. PROMIS scores (except cognitive abilities), and pain centralization and neuropathic pain scores, were higher among recent/current users (each p < 0.0001). Sleep and pain were the most frequently reported reasons for use. Benefit from cannabinoids for sleep and pain were strongly correlated (r = 0.65, p < 0.0001). For those who expressed a preference for specific THC/CBD ratios, CBD-predominant formulations were favored.

Conclusion

Cannabinoid use is common in PwMS, despite a paucity of provider guidance. The range of perceived benefits, and potential differential effects of THC and CBD, highlight the need for personalized, evidence-based guidelines regarding cannabinoid use.

Widespread Pain Is Associated with Increased Risk of No Clinical Improvement After TKA in Women

BACKGROUND

When conservative treatments do not work, TKA may be the best option for patients with knee osteoarthritis, although a relatively large proportion of individuals do not have clinically important improvement after TKA. Evidence also suggests that women are less likely to benefit from TKA than men, but the reasons are unclear. Widespread pain disproportionately affects women and has been associated with worse outcomes after joint arthroplasty, yet it is unknown if the effect of widespread pain on TKA outcomes differs by patient gender.

QUESTIONS/PURPOSES

(1) Does the association between widespread pain and no clinically important improvement in osteoarthritis-related pain and disability 2 years after TKA differ between men and women? (2) Does the use of pain medications 2 years after TKA differ between those with widespread pain and those without widespread pain before surgery?

METHODS

Osteoarthritis Initiative (https://nda.nih.gov/oai/) study participants were followed annually from March 2005 until October 2015. Participants who underwent TKA up to the 7-year follow-up visit with pain/disability assessment at the protocol-planned visit before TKA and at the second planned annual visit after surgery were included in the analysis. Among 4796 study participants, 391 had a confirmed TKA, including 315 with pain/disability assessment at the protocol-planned visit before TKA. Overall, 95% of participants (298) had the required follow-up assessment; 5% (17) did not have follow-up data. Widespread pain was defined based on the modified American College of Rheumatology criteria. Symptoms were assessed using the WOMAC pain (range 0 to 20; higher score, more pain) and disability (range 0 to 68; higher score, more disability) scores, and the Knee Injury and Osteoarthritis Outcome Score for pain (range 0 to 100; higher score, less pain). Improvements in pain and disability were classified based on improvement from established clinically important differences (decrease in WOMAC pain ≥ 1.5; decrease in WOMAC disability ≥ 6.0; increase in Knee Injury and Osteoarthritis Outcome Score for pain ≥ 9). At baseline, more women presented with widespread pain than men (45% [84 of 184] versus 32% [36 of 114]). Probability and the relative risk (RR) of no clinically important improvement were estimated using a logistic regression analysis in which participants with widespread pain and those without were compared. The analyses were done for men and women separately, then adjusted for depression and baseline outcome scores.

RESULTS

Among women, preoperative widespread pain was associated with an increased risk of no clinically important improvement 2 years after TKA, based on WOMAC pain scores (13.5% versus 4.6%; RR 2.93 [95% CI 1.18 to 7.30]; p = 0.02) and the Knee Injury and Osteoarthritis Outcome Score for pain (16.5% versus 4.9%; RR 3.39 [95% CI 1.34 to 8.59]; p = 0.02). Given the lower and upper limits of the confidence intervals, our data are compatible with a broad range of disparate associations between widespread pain and lack of clinically important improvement in WOMAC pain scores (RR 0.77 [95% CI 0.22 to 2.70]; p = 0.68) and the Knee Injury and Osteoarthritis Outcome Score for pain (RR 1.37 [95% CI 0.47 to 4.00]; p = 0.57) among men, as well as clinically important improvement in WOMAC disability scores among men (RR 0.72 [95% CI 0.20 to 2.55]; p = 0.61) and women (RR 1.98 [95% CI 0.92 to 4.26]; p = 0.08). Participants presenting with widespread pain before TKA were more likely than those without widespread pain to use medication for symptoms of knee osteoarthritis most days for at least 1 month 2 years after TKA (51% [61 of 120] versus 32% [57 of 178]; mean difference, 18.8 [95% CI 7.3 to 30.1]; p < 0.01).

CONCLUSIONS

Widespread pain before TKA was associated with an increased risk of no clinically important improvement in knee pain 2 years postoperatively among women. Because of the small number of men with widespread pain in the sample, the results for men were inconclusive. In clinical practice, screening TKA candidates for widespread pain may be useful, and expectations of surgical outcomes may need to be tempered if patients have a concurrent diagnosis of widespread pain. Future studies should include more men with widespread pain and investigate if treatment of widespread pain before or concurrent with TKA surgery may improve surgical outcomes.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Opioid Prescribing and Use Patterns in Postsurgical Facial Trauma Patients

BACKGROUND

Facial fractures are painful injuries routinely managed by opioids after surgical repair. Studies have identified patient risk factors and prescribing patterns associated with opioid use in medicine and general surgery; however, little is known about these entities in the facial trauma population.

METHODS

A retrospective cohort study of opioid-naive patients undergoing surgical repair of facial fractures was conducted using the Truven Health MarketScan Commercial Claims and Encounters (2006 to 2015) and Medicaid Multi-State Databases (2011 to 2015). Eligible procedures included nasal, nasoorbitoethmoid, orbital, mandible, and Le Fort fracture repair. Opioid type, daily dosage, and prescription duration were analyzed. Multivariable logistic regression was performed to determine independent predictors of prescription refill.

RESULTS

A total of 20,191 patients undergoing surgical repair of facial fractures were identified. Of these, 15,861 patients (78.6 percent) filled a perioperative opioid prescription. Refill (58.7 percent) and potentially inappropriate prescribing (39.4 percent) were common among this population. Patient factors including prior substance use (adjusted OR, 1.84; 95 percent CI, 1.63 to 2.07) and history of mental health disorder (adjusted OR, 1.43; 95 percent CI, 1.06 to 1.91) were independent predictors of refill. Increased odds of refill were seen in patients prescribed tramadol (OR, 1.98; 95 percent CI, 1.48 to 2.66) and those who underwent multiple surgical repairs (OR, 3.38; 95 percent CI, 2.54 to 4.50).

CONCLUSIONS

Refill and potentially inappropriate prescribing occurred at high rates in facial trauma patients undergoing surgical repair. Additional studies are needed to develop guidelines for proper opioid prescribing in this population.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Pain and Opioid Use After Thoracic Surgery: Where We Are and Where We Need To Go

As many as one third of patients undergoing minimally invasive thoracic surgery and one half undergoing thoracotomy will have chronic pain, defined as pain lasting 2 to 3 months. There is limited information regarding predictors of chronic pain and even less is known about its impact on health-related quality of life, known as pain interference. Currently, there is a focus on decreased opioid prescribing after surgery. Interestingly, thoracic surgical patients are the least likely to be receiving opioids before surgery and have the highest rate of new persistent opioid use after surgery compared with other surgical cohorts. These studies of opioid use have identified important predictors of new persistent opioid use, but their findings are limited by failing to correlate opioid use with pain. The objectives of this invited review are to present the findings of pertinent studies of chronic pain and opioid use after thoracic surgery, "where we are," and to discuss gaps in our knowledge of these topics and opportunities for research to fill those gaps, "where we need to go."

All-cause and cause-specific mortality in persons with fibromyalgia and widespread pain: An observational study in 35,248 persons with rheumatoid arthritis, non-inflammatory rheumatic disorders and clinical fibromyalgia

PURPOSE

Studies of the relation of fibromyalgia (FM) and widespread pain (WSP) to mortality have differed as to the presence or absence of an association and the extent of cause-specific mortality. However, no studies have investigated which definitions of FM and WSP associate with mortality, nor of FM mortality in other diseases. We investigated these issues and the meaning of mortality in patients with FM.

METHODS

We used Cox regression to study 35,248 rheumatic disease patients with up to 16 years of mortality follow-up in all patients and separately in those with diagnoses of rheumatoid arthritis (RA) (N = 26,458), non-inflammatory rheumatic disorders (NIRMD) (N = 5,167) and clinically diagnosed FM (N = 3,659). We applied 2016 FM criteria and other FM and WSP criteria to models adjusted for age and sex as well as to models that included a full range of covariates, including comorbid disease and functional status. We estimated the degree of explained of variance (R2) as a measure of predictive ability.

RESULTS

We found positive associations between al`l definitions of FM and WSP and all-cause mortality, with relative risks (RR)s ranging from 1.19 (95%CI 1.15-1.24) for American College of Rheumatology (ACR) 1990 WSP to 1.38 (1.31-1.46) in age and sex adjusted revised 2016 criteria (FM 2016). However, in full covariate models the FM 2016 RR reduced further to 1.15 (1.09-1.22). The association with mortality was noted with RA (1.52 (1.43-1.61)), NIRMD (1.43 (1.24-1.66)) and clinical FM (1.41 (1.14-1.75) - where 37% of FM diagnosed patients did not satisfy FM 2016 criteria. In the all-patient analyses, the age and sex explained variation (R2) was 0.255, increasing to 0.264 (4.4%) when FM 2016 criteria were added, and to 0.378 in a full covariate model. Death causes related to FM 2016 status included accidents, 1.45 (1.11-1.91); diabetes 1.78 (1.16-2,71); suicide, 3.01 (1.55-5.84) and hypertensive related disorders, 3.01 (1.55-5.84). Cancer deaths were less common 0.77 (0.68-0.88).

CONCLUSIONS

FM is weakly associated with mortality within all criteria definitions of FM and WSP examined (3.4% of explained variance), and across all diseases (RA, NIRMD, clinical FM) equally. Clinical and criteria-defined FM had different mortality outcomes. We found no evidence for a positive association of cancer and FM or WSP.

Outcomes in Long-term Opioid Tapering and Buprenorphine Transition: A Retrospective Clinical Data Analysis

Background

There are significant medical risks of long-term opioid therapy (LTOT) for chronic pain. Consequently, there is a need to identify effective interventions for the reduction of high-dose full-agonist opioid medication use.

Methods

The current study details a retrospective review of 240 patients with chronic pain and LTOT presenting for treatment at a specialty opioid refill clinic. Patients first were initiated on an outpatient taper or, if taper was not tolerated, transitioned to buprenorphine. This study analyzes potential predictors of successful tapering, successful buprenorphine transition, or failure to complete either intervention and the effects of this clinical approach on pain intensity scores.

Results

One hundred seven patients (44.6%) successfully tapered their opioid medications under the Centers for Disease Control and Prevention guideline target dose (90 mg morphine-equianalgesic dosage), 45 patients (18.8%) were successfully transitioned to buprenorphine, and 88 patients (36.6%) dropped out of treatment: 11 patients during taper, eight during buprenorphine transition, and 69 before initiating either treatment. Conclusions. Higher initial doses of opioids predicted a higher likelihood of requiring buprenorphine transition, and a co-occurring benzodiazepine or z-drug prescription predicted a greater likelihood of dropout from both interventions. Patterns of change in pain intensity according to treatment were mixed: among successfully tapered patients, 52.8% reported greater pain and 23.6% reported reduced pain, whereas 41.8% reported increased pain intensity and 48.8% reported decreased pain after buprenorphine transition. Further research is needed on predictors of treatment retention and dropout, as well as factors that may mitigate elevated pain scores after reduction of opioid dosing.

Association of Opioid Use With Pain and Satisfaction After Dental Extraction

IMPORTANCE

Dentists commonly prescribe opioids to relieve pain after tooth extraction. Understanding the differences in patient-reported outcomes between opioid users and nonusers could encourage the adoption of more conservative and appropriate prescribing practices in dental medicine.

OBJECTIVE

To evaluate whether pain and satisfaction scores reported by patients who used opioids after tooth extraction were similar to the levels reported by patients with no opioid use.

DESIGN, SETTING, AND PARTICIPANTS

This quality improvement study was conducted in the 14 dental clinics of the University of Michigan School of Dentistry. Eligible adult patients of these clinics who underwent routine or surgical extractions between June 1, 2017, and December 31, 2017, were contacted by telephone within 6 months of the procedure. Patients were surveyed about the type of extraction, use of prescription opioid (if given), use of nonopioid analgesics, pain levels, and satisfaction with care after the procedure. Data analysis was conducted from February 1, 2018, to July 31, 2018.

MAIN OUTCOMES AND MEASURES

The primary outcome was self-reported pain as assessed by the question, "Thinking back, how would you rate your pain in the first week after your dental procedure?" with a 4-point pain scale of no pain, minimal pain, moderate pain, or severe pain. Secondary outcomes included self-reported satisfaction with care as assessed by a Likert scale ranging from 1 to 10, in which 1 was extremely dissatisfied and 10 was extremely satisfied.

RESULTS

The final cohort comprised 329 patients, of whom 155 (47.1%) underwent surgical extraction (mean [SD] age, 41.8 [18.1] years; 80 [51.6%] were men) and 174 (52.9%) underwent routine extraction (mean [SD] age, 52.4 [17.9] years; 79 [45.4%] were men). Eighty patients (51.6%) with surgical extraction and 68 (39.1%) with routine extraction used opioids after their procedure. In both extraction groups, patients who used opioids reported higher levels of pain compared with those who did not use opioids (surgical extraction group: 51 [63.8%] vs 34 [45.3%], P < .001; routine extraction group: 44 [64.7%] vs 35 [33.0%], P < .001). No statistically significant difference in satisfaction was found between groups after surgical extraction (median [interquartile range] scores: 9 [7-10] for nonopioid group vs 9 [8-10] for opioid group) and routine extraction (median [interquartile range] scores: 10 [8-10] for nonopioid group vs 9 [7-10] for opioid group).

CONCLUSIONS AND RELEVANCE

This study found that patients who used opioids after tooth extraction reported significantly higher levels of pain compared with nonusers, but no difference in satisfaction was observed.

Top down or bottom up? An observational investigation of improvement in fibromyalgia symptoms following hip and knee replacement

OBJECTIVES

Many patients with osteoarthritis have comorbid symptoms of FM, but it is unknown how these symptoms respond to surgical procedures that address nociceptive input in the periphery, such as total joint replacement. Here we explore differences in clinical characteristics between patients whose FM symptoms do and do not improve following total hip or knee replacement.

METHODS

Participants were 150 patients undergoing knee or hip replacement who had a minimum FM survey score of 4 or greater prior to surgery. The top tertile of patients experiencing the most improvement in FM symptoms at month 6 were categorized as 'Improve' (n = 48) while the bottom two tertiles were categorized as 'Worsen/Same' (n = 102). Baseline symptom characteristics were compared between groups, as well as improvement in overall pain severity, surgical pain severity and physical function at 6 months.

RESULTS

The Worsen/Same group had higher levels of fatigue, depression and surgical site pain at baseline (all P < 0.05). Additionally, they improved less on overall pain severity and physical functioning 6 months after surgery (both P < 0.05).

CONCLUSION

Most patients derive significant benefit in improvement of comorbid FM symptoms following total joint replacement, but a substantial proportion do not. Understanding the neurobiological basis for these different trajectories may help inform clinical judgment and improve patient care.

Predictors of Pain, Function, and Change in Patellofemoral Pain

BACKGROUND

Identification of factors predictive of outcome and change is important to improve treatment for patellofemoral pain (PFP). Few studies have examined the predictive value of psychological factors in PFP, although they have been reported to be important predictors in other musculoskeletal pain conditions.

PURPOSE

To evaluate predictors of pain, function, and change 1 year after an exercise-based intervention in PFP.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In sum, 112 patients were recruited to a randomized controlled trial; 98 attended 1-year follow-up. There were no between-group differences in the trial; thus, the material was analyzed as 1 cohort. Nine baseline factors-sex, bilateral pain, worst pain, pain duration, Anterior Knee Pain Scale (AKPS), kinesiophobia, anxiety and depression, self-efficacy, and number of pain sites throughout the body-were investigated for their predictive ability on outcome at 1 year (AKPS, worst pain) and for change at 1 year (global change score, change in AKPS, and change in worst pain). Multivariable linear regression models with stepwise backward removal method were used to find predictors of poor outcome.

RESULTS

Number of pain sites at baseline was a significant predictor of worse outcome for AKPS (B = -2.7; 95% CI, -4.0 to -1.3; P < .01), worst pain (B = 0.5; 95% CI, 0.2-0.8; P < .01), global change (B = -0.8; 95% CI, -1.2 to -0.5; P < .01), change in AKPS (B = -2.7; 95% CI, -4.0 to -1.3; P < .01), and change in worst pain (B = 0.5, 95% CI, 0.2-0.8; P < .01) at 1 year. Baseline scores for AKPS and worst pain predicted respective 1-year levels and change scores (P < .01). Lower self-efficacy and male sex predicted less global change (P < .01). Longer pain duration predicted final score and change score for worst pain (P < .01). The predictive models had reasonable fit with adjusted R² from 0.22 to 0.35.

CONCLUSION

Higher number of pain sites throughout the body was a consistent predictor of poor outcome and less change at 1 year. Baseline levels for AKPS and worst pain predicted respective final scores and change scores.

REGISTRATION

NCT02114294 ( ClinicalTrials.gov identifier).

Centralized pain and pain catastrophizing mediate the association between lifetime abuse history and self-reported pain medication side effects

Background

Self-reported side effects of pain medication are important determinants of treatment course that can affect patient adherence, medication discontinuation and physician decisions. Yet, few studies have investigated patient-level predictors of self-reported pain medication side effects. The present study sought to fill this gap by exploring the impact of physical or sexual abuse history on self-reported pain medication side effects and considered a mediation model in which those effects are transmitted through a centralized pain phenotype and pain catastrophizing.

Methods

We conducted a cross-sectional analysis of 3118 patients presenting to a tertiary-care, outpatient pain clinic.

Results

Approximately 15% of the sample (n=479) reported a lifetime history of abuse. Patients with a lifetime history of abuse, particularly abuse that occurred in both childhood and adulthood, reported more pain medication side effects compared with patients reporting no abuse history. Furthermore, path analysis showed that a centralized pain phenotype and pain catastrophizing mediated the association between lifetime abuse history and the sum of pain medication side effects.

Conclusions

This suggests that individuals who experience abuse may develop a heightened physiological sensitivity to stimuli, as well as a tendency to interpret stimuli negatively, exaggerate the impact of aversive stimuli and undermine their ability to cope with the stressor. This study highlights the need for physicians to understand patient-level predictors of medication tolerance and to consider a history of abuse and trauma in decisions regarding treatment and medication management.

Patient-Reported Outcomes: Understanding Surgical Efficacy and Quality from the Patient's Perspective

In surgery, quality assessment encourages improved care delivery, better outcomes, and helps determine surgical efficacy. Quality is important from a patient, provider, payer, and policy maker standpoint. However, given the growth of outpatient procedures, expansion of surgical indications to enhance function, and the decline of perioperative morbidity and mortality, many traditional quality metrics, such as mortality, readmissions, and complications, may not fully capture quality. As such, patient-reported outcomes (PROs) can be used to complement the established clinical outcomes and describe surgical efficacy and quality from the patient's point of view. Generic and disease-specific PRO measures capture health-related quality of life, functional status, and pain. These measures permit a more holistic understanding of how surgery affects different aspects of a patient's health, augment other clinical outcomes, and are commonly used to determine efficacy in clinical trials. Moreover, our national reimbursement structure is currently evolving to include PROs for certain surgical conditions in measures of quality and with direct linkage to payments. Even so, there continues to be challenges in the implementation of PRO measures in everyday surgical practice, with questions of optimal administration and how to integrate these measures into provider work flow. Despite these challenges, PROs provide vital information regarding surgical efficacy and quality and are critical in the delivery of patient-centered care.

Initial validation of the electronic form of the Michigan Body Map

BACKGROUND

The Michigan Body Map (MBM) was developed to assess pain location in a reliable and valid manner; however, electronic formats have not been validated. This study had two aims: (1) initial validation of the electronic form of the MBM (eMBM) and (2) preliminary test of assessing pain severity within body zones.

METHODS

For the first aim, 68 participants with chronic pain completed paper and electronic forms of the MBM, then underwent scripted interviews to assess preferences among body maps and verbal confirmation of pain locations. For the second aim, a subset of the participants (n=40) completed the Brief Pain Inventory (BPI) pain severity subscale, as well as the eMBM again and endorsed pain severity using additional screens showing body zones that contained areas in which pain was endorsed.

RESULTS

There were few discrepancies between MBM, eMBM and verbal report (1.9% and 1.6%, respectively), and no difference between forms in perceived ability to indicate areas of pain or ease of completion. Patients accurately indicated their bodily pain on both maps, with 84% and 87% reporting one or no errors on MBM and eMBM, respectively. Participants also reported no preference for which version best-depicted areas of pain or best distinguished left from right. Lastly, the most preferred measure was eMBM with pain severity zones, followed by eMBM without zones, followed by the BPI pain severity subscale.

CONCLUSIONS

These data support the validity of the eMBM for patients with chronic pain. Further, an expanded form of the eMBM that assesses pain severity was preferred by most participants.

Association Between the 2011 Fibromyalgia Survey Criteria and Multisite Pain Sensitivity in Knee Osteoarthritis

OBJECTIVES

The present study evaluated the relationship between the 2011 American College of Rheumatology fibromyalgia (FM) survey criteria and quantitative sensory testing (QST).

MATERIALS AND METHODS

Patients with knee osteoarthritis scheduled to undergo knee arthroplasty completed the FM survey criteria and self-report measures assessing clinical symptoms. Patients also underwent a battery of QST procedures at the surgical knee and remote body sites, including pressure algometry, conditioned pain modulation, and temporal summation. All assessments were completed before surgery. FM survey criteria were used to calculate a continuous FM score indicating FM severity.

RESULTS

A total of 129 patients were analyzed. Of these, 52.7% were female, 93.8% were Caucasian, and 3.8% met the FM survey criteria for FM classification. Mean age for females (63.6 y) and males (64.7 y) was similar. Females and males differed significantly in nearly every outcome, including FM severity, clinical pain, anxiety, depression, and pressure pain sensitivity. In females, FM scores significantly correlated with pressure pain sensitivity, but not conditioned pain modulation or temporal summation, such that increased sensitivity was associated with greater FM severity at all body sites examined. In addition, as FM scores increased, the association between pain sensitivity at the surgical knee and pain sensitivity at remote body sites also increased. No relationship between FM score and QST was observed in males.

DISCUSSION

We demonstrated an association between diffuse hyperalgesia as measured by QST and FM severity in females with knee osteoarthritis. These results suggest that the FM survey criteria may represent a marker of pain centralization in females with potential utility in clinical decision making.

Prevalence of Preoperative Opioid Use and Characteristics Associated With Opioid Use Among Patients Presenting for Surgery

Importance

Patterns of preoperative opioid use are not well characterized across different surgical services, and studies in this patient population have lacked important self-reported data of pain and affect.

Objectives

To assess the prevalence of preoperative opioid use and the characteristics of these patients in a broadly representative surgical cohort.

Design, Setting, and Participants

Cross-sectional, observational study of patients undergoing surgery at a tertiary care academic medical center. Data were collected as a part of large prospective institutional research registries from March 1, 2010, through April 30, 2016.

Exposures

Preoperative patient and procedural characteristics, including prospectively assessed self-reported pain and functional measures.

Main Outcomes and Measures

Patient-reported opioid use before surgery.

Results

Of the total 34 186 patients recruited (54.2% women; mean [SD] age, 53.1 [16.1] years), preoperative opioid use was reported in 7894 (23.1%). The most common opioids used were hydrocodone bitartrate (4685 [59.4%]), tramadol hydrochloride (1677 [21.2%]), and oxycodone hydrochloride (1442 [18.3%]). Age of 31 to 40 years (adjusted odds ratio [aOR], 1.26; 95% CI, 1.10-1.45), tobacco use (former use aOR, 1.32 [95% CI, 1.22-1.42]; current use aOR, 1.62 [95% CI, 1.48-1.78]), illicit drug use (aOR, 1.74; 95% CI, 1.16-2.60), higher pain severity (aOR, 1.33; 95% CI, 1.31-1.35), depression (aOR, 1.22; 95% CI, 1.12-1.33), higher Fibromyalgia Survey scores (aOR, 1.06, 95% CI, 1.05-1.07), lower life satisfaction (aOR, 0.95, 95% CI, 0.93-0.96), and more medical comorbidities (American Society of Anesthesiology score aOR, 1.47 [95% CI, 1.37-1.58]; Charlson Comorbidity Index aOR, 1.29 [95% CI, 1.18-1.41]) were all independently associated with preoperative opioid use. Preoperative opioid use was most commonly reported by patients undergoing orthopedic (226 [65.1%]) and neurosurgical spinal (596 [55.1%]) procedures and least common among patients undergoing thoracic procedures (244 [15.7%]). After adjusting for patient characteristics, the patients undergoing lower extremity procedures were most likely to report preoperative opioid use (aOR, 3.61; 95% CI, 2.81-4.64), as well as those undergoing pelvic (excluding hip) (aOR, 3.09; 95% CI, 1.88-5.08), upper extremity (aOR, 3.07; 95% CI, 2.12-4.45), and spinal or spinal cord (aOR, 2.68; 95% CI, 2.15-3.32) procedures, with the group undergoing intrathoracic surgery as the reference group.

Conclusions and Relevance

In this large study of preoperative opioid use that includes patient-reported outcome measures, more than 1 in 4 patients presenting for surgery reported opioid use. These data provide important insights into this complicated patient population that would appear to help guide future preoperative optimization and perioperative opioid-weaning interventions.

Fibromyalgia and Shoulder Surgery: A Systematic Review and a Critical Appraisal of the Literature

Fibromyalgia is a common musculoskeletal syndrome characterized by chronic widespread pain and other systemic manifestations, which has demonstrated a contribution to higher postoperative analgesic consumption to other surgeries such as hysterectomies and knee and hip replacements. The aim of this review is to search current literature for studies considering the impact of fibromyalgia on clinical outcomes of patients undergoing shoulder surgery. A systematic literature review was conducted in PubMed/Medline, Embase, and ClinicalTrials.gov in February 2019. Studies were selected based on the following participants, interventions, comparisons, outcomes, and study design criteria: adult patients undergoing surgery for shoulder pain (P); diagnosis of fibromyalgia (I); patients without fibromyalgia (C); outcome of surgery in terms of pain or analgesic or non-steroidal anti-inflammatory drugs consumption (O); case series, retrospective studies, observational studies, open-label studies, randomized clinical trials, systematic reviews and meta-analyses were included (S). Authors found 678 articles, of which four were found eligible. One retrospective study showed that patients with fibromyalgia had worse clinical postoperative outcomes; two retrospective studies reported a higher opioid prescription in patients with fibromyalgia and one prospective observational study found that a higher fibromyalgia survey score correlated with lower quality of recovery scores two days after surgery. The scarce and low-quality evidence available does not allow confirming that fibromyalgia has an impact on postoperative outcomes in shoulder surgery. Future studies specifically focusing on shoulder surgery outcomes may help improvement and personalization of the management of patients with fibromyalgia syndrome (PROSPERO 2019, CRD42019121180).

Probability of Opioid Prescription Refilling After Surgery: Does Initial Prescription Dose Matter?

OBJECTIVE

We sought to determine the correlation between the probability of postoperative opioid prescription refills and the amount of opioid prescribed, hypothesizing that a greater initial prescription yields a lower probability of refill.

BACKGROUND

Although current guidelines regarding opioid prescribing largely address chronic opioid use, little is known regarding best practices and postoperative care.

METHODS

We analyzed Optum Insight claims data from 2013 to 2014 for opioid-naïve patients aged 18 to 64 years who underwent major or minor surgical procedures (N = 26,520). Our primary outcome was the occurrence of an opioid refill within 30 postoperative days. Our primary explanatory variable was the total oral morphine equivalents provided in the initial postoperative prescription. We used logistic regression to examine the probability of an additional refill by initial prescription strength, adjusting for patient factors.

RESULTS

We observed that 8.67% of opioid-naïve patients refilled their prescriptions. Across procedures, the probability of a single postoperative refill did not change with an increase with initial oral morphine equivalents prescribed. Instead, patient factors were correlated with the probability of refill, including tobacco use [odds ratio (OR) 1.42, 95% confidence interval (CI) 1.23-1.57], anxiety (OR 1.30, 95% CI 1.15-1.47), mood disorders (OR 1.28. 95% CI 1.13-1.44), alcohol or substance abuse disorders (OR 1.43, 95% CI 1.12-1.84), and arthritis (OR 1.21, 95% CI 1.10-1.34).

CONCLUSIONS

The probability of refilling prescription opioids after surgery was not correlated with initial prescription strength, suggesting surgeons could prescribe smaller prescriptions without influencing refill requests. Future research that examines the interplay between pain, substance abuse, and mental health could inform strategies to tailor opioid prescribing for patients.

Fibromyalgia Increases the Risk of Surgical Complications Following Total Knee Arthroplasty: A Nationwide Database Study

BACKGROUND

Although fibromyalgia is a common comorbidity with knee osteoarthritis, the orthopedic literature on this population is limited. Therefore, the purpose of this study is to assess if fibromyalgia patients have a higher likelihood of developing surgical complications after total knee arthroplasty (TKA) than a matched control cohort.

METHODS

The Medicare Standard Analytical Files of the PearlDiver supercomputer was utilized to identify patients who underwent a TKA between 2005 and 2014. Patients were 1:1 propensity score matched based on the diagnosis of fibromyalgia, age, gender, and the Charlson Comorbidity Index, yielding a total of 305,510 patients. Odds ratios (ORs), 95% confidence intervals (95% CIs), and P-values (<.05) were calculated to examine the likelihood of developing any surgical complication, as well as specific surgical complications.

RESULTS

Compared to a matched cohort, fibromyalgia patients had increased odds of developing any surgical complication (OR 1.55, 95% CI 1.51-1.60, P < .001), such as bearing wear (OR 2.11, 95% CI 1.48-3.01, P < .0001) and periprosthetic osteolysis (OR 1.71, 95% CI 1.10-2.66, P = .018). Furthermore, these patients had significantly greater odds of developing revision of tibial insert (OR 1.5, 95% CI 1.14-2.05, P = .046), mechanical loosening (OR 1.34, 95% CI 1.26-1.53, P < .0001), infection/inflammation (OR 1.33, 95% CI 1.26-1.14, P < .0001), dislocations (OR 1.33, 95% CI 1.21-1.47, P < .0001), as well as other complications (OR 1.74, 95% CI 1.68-1.80, P < .0001).

CONCLUSION

This analysis of over 300,000 patients identified that fibromyalgia patients can have a greater risk of developing certain surgical complications after TKA. Therefore, fibromyalgia patients must be made aware of the increased postoperative risks and surgeons should consider enhanced preoperative medical and surgical optimization.

New and emerging treatments for vaso-occlusive pain in sickle cell disease

Introduction: Acute pain from episodic vaso-occlusion (VOC) spans the lifespan of almost everyone with sickle cell disease (SCD), while additional chronic pain develops in susceptible individuals in early adolescences. Frequent acute pain with chronic pain causes significant physical and psychological morbidity, and frequent health-care utilization. Available pharmacologic therapies reduce acute pain frequency but few evidence-based therapies are available for chronic pain. Areas covered: An extensive PubMed literature search was performed with appropriate search criteria. The pathophysiology of acute pain from VOC in SCD is very complex with many events subsequent to sickle polymer formation. Sensitization of pain pathways and alterations of brain networks contributes to the experience of chronic pain. Numerous therapies targeting putative VOC mechanisms are in clinical trials, and show considerable promise. Alternative analgesic treatments for acute and chronic pain have been examined in small patient cohorts, but formal clinical trials are lacking. Expert opinion: Childhood is likely a critical window for prevention of acute and later chronic pain. New multimodal analgesic therapies are needed, particularly for chronic pain, and should be examined in clinical trials. Given the multifactorial nature of both pain and VOC, simultaneously targeting multiple mechanisms may be the optimal approach for effective preventive therapies.

Risk Factors for Opioid Use After Anterior Cruciate Ligament Reconstruction

BACKGROUND

The misuse of opioid medications has contributed to a significant national crisis affecting public health as well as patient morbidity and medical costs. After orthopaedic surgical procedures, patients may require prescription (Rx) opioid medication, which can fuel the opioid epidemic. Opioid Rx usage after anterior cruciate ligament reconstruction (ACLR) is not well characterized.

PURPOSE

To determine baseline utilization of Rx opioids in patients undergoing ACLR and examine demographic, patient, and surgical factors associated with greater and prolonged postoperative opioid utilization.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Primary elective ACLRs were identified using Kaiser Permanente's ACLR registry (2005-2015). We studied the association of perioperative risk factors on the number of dispensed opioid Rx in the early (0-90 days) and late (91-360 days) postoperative recovery periods using logistic regression.

RESULTS

Of 21,202 ACLRs, 25.5% used at least 1 opioid Rx in the 1-year preoperative period; 17.7% and 2.7% used ≥2 opioid Rx in the early and late recovery periods, respectively. Risk factors associated with greater opioid Rx in both the early and the late periods included the following: ≥2 preoperative opioid Rx, age ≥20 years, American Society of Anesthesiologists classification ≥3, other activity at the time of injury, chondroplasty, chronic pulmonary disease, and substance abuse. Risk factors associated with opioid Rx use during the early period only included the following: other race, acute injury, meniscal injury repair, multiligament injury, and dementia/psychosis. Risk factors associated with greater opioid Rx during the late period only included the following: 1 preoperative opioid Rx, female sex, body mass index ≥25 kg/m², motor vehicle accident as the mechanism of injury, and hypertension.

CONCLUSION

A quarter of ACLR patients had at least 1 opioid Rx before the procedure, but usage dropped to 2.7% toward the end of the postoperative year. We identified several perioperative risk factors for greater and prolonged opioid usage after ACLR.

A Multi-faceted Educational Approach for Pain Metric Recording Prior to Knee and Hip Arthroplasty: Effects on Documentation by an Acute Pain Service

Background

Despite the increased use of electronic medical records (EMRs) in past years, the recording of clinically useful baseline pain information may still be lacking. An educational effort targeted at the acute pain service and reinforced by electronic prompting may be an effective way to promote electronic documentation of relevant pain metrics. The objective of this study was to assess whether an educational effort with electronic prompting in the EMR promotes the documentation of baseline pain scores and preoperative opioid use by an acute pain service (APS).

Methods

A total of 98 patients were included in this study: 49 in the study group and 49 in the control group. The study group consisted of patients who underwent knee and hip arthroplasties after the institution of a multimodal analgesia educational program that also incorporated an electronic prompt to promote behavior change. Primary outcomes were the frequency of documentation of baseline pain scores and preoperative opioid use.

Results

After the implementation of the education initiative, 67% of the patients had baseline pain scores recorded in the preoperative APS documentation, compared to 20% in the control group (p = 0.0001). Preoperative opioid use was recorded in 24% of APS documentation within the control group, but this increased to 73% after the educational intervention (p = 0.0001). Documentation of resting pain scores on the day of surgery also increased from 59% to 87% (p = 0.0014).

Conclusions

The introduction of a multi-dimensional educational effort focused on baseline pain metric recording within the context of an analgesic change of practice increased assessment of both baseline pain and preoperative opioid use by APS. These results can be applied to other settings in which a focused change of practice is required and an electronic medical record already utilized.

Evaluating the psychometric properties of the Widespread Pain Index and the Symptom Severity scale in youth with painful conditions

Background

Assessing features of centralized pain may prove to be clinically meaningful in pediatric populations. However, we are currently limited by the lack of validated pediatric measures.

Aim

We examined the psychometric properties of the Widespread Pain Index (WPI) and Symptom Severity (SS) scale, to assess features of centralized pain, in youth with painful conditions from three clinical samples: (1) musculoskeletal surgery, (2) headache, and (3) chronic pain.

Methods

Participants were 240 youth aged 10-18 years (Mage=14.8, SD=1.9) who completed the WPI and SS scale. Subsets of participants also completed additional measures of pain region, pain intensity, quality of life, pain interference and physical function.

Results

Increased features of centralized pain by age were seen for the WPI (r=0.27, p<0.01) and SS scale (r=0.29, p<0.01). Expected differences in sex were seen for the WPI (sex:t₁₃₂=-3.62, p<0.01), but not the SS scale (sex:t₂₂₃=-1.73, p=0.09). Reliability for the SS scale was adequate (α=.70). Construct validity was demonstrated through relationships between the WPI and pain regions (r=.57, p<0.01), and between the SS scale and quality of life (r=-.59, p<0.01) and pain interference (r=.56, p<0.01). Criterion validity was demonstrated by differences on the WPI between the surgery sample and the headache and chronic pain samples (F_2,237=17.55, p<0.001). Comprehension of the SS scale items was problematic for some youth.

Conclusions

The WPI showed adequate psychometric properties in youth; however the SS scale may need to be modified. Our findings support the need to develop psychometrically sound instruments for comprehensive assessment of pain in pediatric samples.

The association between endogenous opioid function and morphine responsiveness: a moderating role for endocannabinoids

We sought to replicate previous findings that low endogenous opioid (EO) function predicts greater morphine analgesia and extended these findings by examining whether circulating endocannabinoids and related lipids moderate EO-related predictive effects. Individuals with chronic low-back pain (n = 46) provided blood samples for endocannabinoid analyses, then underwent separate identical laboratory sessions under 3 drug conditions: saline placebo, intravenous (i.v.) naloxone (opioid antagonist; 12-mg total), and i.v. morphine (0.09-mg/kg total). During each session, participants rated low-back pain intensity, evoked heat pain intensity, and nonpain subjective effects 4 times in sequence after incremental drug dosing. Mean morphine effects (morphine-placebo difference) and opioid blockade effects (naloxone-placebo difference; to index EO function) for each primary outcome (low-back pain intensity, evoked heat pain intensity, and nonpain subjective effects) were derived by averaging across the 4 incremental doses. The association between EO function and morphine-induced back pain relief was significantly moderated by endocannabinoids [2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA)]. Lower EO function predicted greater morphine analgesia only for those with relatively lower endocannabinoids. Endocannabinoids also significantly moderated EO effects on morphine-related changes in visual analog scale-evoked pain intensity (2-AG), drug liking (AEA and 2-AG), and desire to take again (AEA and 2-AG). In the absence of significant interactions, lower EO function predicted significantly greater morphine analgesia (as in past work) and euphoria. Results indicate that EO effects on analgesic and subjective responses to opioid medications are greatest when endocannabinoid levels are low. These findings may help guide development of mechanism-based predictors for personalized pain medicine algorithms.

The Society for Pediatric Anesthesia recommendations for the use of opioids in children during the perioperative period

Opioids have long held a prominent role in the management of perioperative pain in adults and children. Published reports concerning the appropriate, and inappropriate, use of these medications in pediatric patients have appeared in various publications over the last 50 years. For this document, the Society for Pediatric Anesthesia appointed a taskforce to evaluate the available literature and formulate recommendations with respect to the most salient aspects of perioperative opioid administration in children. The recommendations are graded based on the strength of the available evidence, with consensus of the experts applied for those issues where evidence is not available. The goal of the recommendations was to address the most important issues concerning opioid administration to children after surgery, including appropriate assessment of pain, monitoring of patients on opioid therapy, opioid dosing considerations, side effects of opioid treatment, strategies for opioid delivery, and assessment of analgesic efficacy. Regular updates are planned with a re-release of guidelines every 2 years.

Predicting chronic pain after major traumatic injury

Background and aims

Chronic pain after traumatic injury and surgery is highly prevalent, and associated with substantial psychosocial co-morbidities and prolonged opioid use. It is currently unclear whether predicting chronic post-injury pain is possible. If so, it is unclear if predicting chronic post-injury pain requires a comprehensive set of variables or can be achieved only with data available from the electronic medical records. In this prospective study, we examined models to predict pain at the site of injury 3–6 months after hospital discharge among adult patients after major traumatic injury requiring surgery. Two models were developed: one with a comprehensive set of predictors and one based only on variables available in the electronic medical records.

Methods

We examined pre-injury and post-injury clinical variables, and clinical management of pain. Patients were interviewed to assess chronic pain, defined as the presence of pain at the site of injury. Prediction models were developed using forward stepwise regression, using follow-up surveys at 3–6 months. Potential predictors identified a priori were: age; sex; presence of pre-existing chronic pain; intensity of post-operative pain at 6 h; in-hospital opioid consumption; injury severity score (ISS); location of trauma, defined as body region; use of regional analgesia intra- and/or post-operatively; pre-trauma PROMIS Depression, Physical Function, and Anxiety scores; in-hospital Widespread Pain Index and Symptom Severity Score; and number of post-operative non-opioid medications. After the final model was developed, a reduced model, based only on variables available in the electronic medical record was run to understand the “value add” of variables taken from study-specific instruments.

Results

Of 173 patients who completed the baseline interview, 112 completed the follow-up within 3–6 months. The prevalence of chronic pain was 66%. Opioid use increased from 16% pre-injury to 28% at 3–6 months. The final model included six variables, from an initial set of 24 potential predictors. The apparent area under the ROC curve (AUROC) of 0.78 for predicting pain 3–6 months was optimism-corrected to 0.73. The reduced final model, using only data available from the electronic health records, included post-surgical pain score at 6 h, presence of a head injury, use of regional analgesia, and the number of post-operative non-opioid medications used for pain relief. This reduced model had an apparent AUROC of 0.76, optimism-corrected to 0.72.

Conclusions

Pain 3–6 months after trauma and surgery is highly prevalent and associated with an increase in opioid use. Chronic pain at the site of injury at 3–6 months after trauma and surgery may be predicted during hospitalization by using routinely collected clinical data.

Implications

If our model is validated in other populations, it would provide a tool that can be easily implemented by any provider with access to medical records. Patients at risk of developing chronic pain could be selected for studies on preventive strategies, thereby concentrating the interventions to patients who are most likely to transition to chronic pain.

Freedom From Opioids After Total Knee Arthroplasty

BACKGROUND

In the United States, opioids are commonly prescribed to treat knee pain after total knee arthroplasty (TKA). While surgery leads to decreased pain in most patients, a sizable minority continue to experience severe pain and consume opioids chronically after TKA. We sought to determine the population-level effect of TKA on opioid consumption by detailing the pattern of opioid prescriptions before and after surgery.

METHODS

We retrospectively identified US Veterans Health Administration TKA patients from 2010 to 2015. Outpatient opioid prescriptions were identified from 18 months before to 18 months after surgery, and mean daily opioid doses were calculated. Our primary end point was the achievement of opioid-freedom, defined as a period of at least 6 months without opioids. We compared the percentage of patients who were opioid-free preoperatively to the percentage who were opioid-free 18 months after surgery (no prescriptions after postoperative month 12). We identified factors associated with opioid-freedom.

RESULTS

In a cohort of 33,927 patients, 41% were opioid-free in the month before surgery compared to 54% 18 months after surgery (P < .001). Preoperative freedom from opioids (odds ratio, 4.59; 95% confidence interval, 4.34 to 4.85; P < .001) was more strongly associated with postoperative freedom from opioids than patient medical and social factors.

CONCLUSION

TKA was associated with an increase in postoperative freedom from opioids. Low preoperative dose of opioids was more strongly associated with postoperative opioid-freedom than patient characteristics, suggesting that opioid prescription patterns are a chief driver of opioid use after surgery.

LEVEL OF EVIDENCE III

Retrospective cohort study.

Medial branch radiofrequency ablation outcomes in patients with centralized pain

BACKGROUND AND OBJECTIVES

We hypothesized that patients with characteristics of centralized pain (fibromyalgia (FM)-like phenotype) would be less likely to respond to radiofrequency ablation (RFA), which may explain some of the failures of this peripherally directed therapy.

METHODS

We conducted a prospective, observational study of patients undergoing RFA using a number of validated self-report measures of pain, mood and function. The 2011 Fibromyalgia Survey Criteria were used to assess for symptoms of centralized pain and was the primary predictor of interest. We constructed multivariable linear regression models to evaluate covariates independently associated with change in pain 3 months after RFA.

RESULTS

141 patients scheduled for medial branch blocks were enrolled in the study; 55 underwent RFA (51 with complete 3 months' follow-up). Patients with higher FM scores had less improvement in overall body pain; however, this was not statistically significant (adjusted mean change in pain FM+0.41, FM-1.11, p=0.396). In a secondary analysis, the FM score was not associated with change in back pain (p=0.720), with both groups improving equally. This cohort also reported significant improvement in anxiety, physical function, catastrophizing, and sleep disturbance at 3 months after RFA.

CONCLUSIONS

Although patients with high baseline centralized pain exhibited less improvement in overall pain, this trend was not statistically significant, possibly due to insufficient power. The same trend was not seen with change in spine pain with both groups improving equally. Centralized pain patients may have less improvement in overall pain but may have equal improvement in their site-specific pain levels after localized interventions.

Chronic pain syndromes: overlapping phenotypes with common mechanisms

The common chronic pain syndromes of fibromyalgia, regional pain syndrome, and complex regional pain syndrome have been made to appear separate because they have been historically described by different groups and with different criteria, but they are really phenotypically accented expressions of the same processes triggered by emotional distress and filtered or modified by genetics, psychology, and local physical factors.

What Pain Levels Do TSA Patients Experience When Given a Long-acting Nerve Block and Multimodal Analgesia?

BACKGROUND

The pain experience for total shoulder arthroplasty (TSA) patients in the first 2 weeks after surgery has not been well described. Many approaches to pain management have been used, with none emerging as clearly superior; it is important that any approach minimizes postoperative opioid use.

QUESTIONS/PURPOSES

(1) With a long-acting nerve block and comprehensive multimodal analgesia, what are the pain levels after TSA from day of surgery until postoperative day (POD) 14? (2) How many opioids do TSA patients take from the day of surgery until POD 14? (3) What are the PainOUT responses at POD 1 and POD 14, focusing on side effects from opioids usage?

METHODS

From January 27, 2017 to December 6, 2017, 154 TSA patients were identified as potentially eligible for this prospective, institutional review board-approved observational study. Of those, 46 patients (30%) were excluded (either because they were deemed not appropriate for the study, research staff were not available, patients were not eligible, or they declined to participate), and another six (4%) had incomplete followup data and could not be studied, leaving 102 patients (66%) for analysis here. Median preoperative pain with movement was 7 (interquartile range [IQR], 5-9) and 13 of 102 patients used preoperative opioids. All patients received a single-injection bupivacaine interscalene block with adjuvant clonidine, dexamethasone, and buprenorphine. Multimodal analgesia included acetaminophen, NSAIDs, and opioids. The primary outcome was the Numerical Rating Scale (NRS) pain score with movement on POD 14. The NRS pain score ranges from 0 (no pain) to 10 (worst pain possible). Secondary outcomes included NRS pain scores at rest and with movement (day of surgery, and PODs 1, 3, 7 and 14), daily analgesic use from day of surgery to POD 14 (both oral and intravenous), Opioid-Related Symptom Distress Scale (which assesses 12 symptoms ranging from 0 to 4, with 4 being the most distressing; the composite score is the mean of the 12 symptom-specific scores) on POD 1, and the PainOut questionnaire on POD 1 and POD 14. The PainOut questionnaire includes questions rating nausea, drowsiness, itching from 0 (none) to 10 (severe), as well as rating difficulty staying asleep from 0 (does not interfere) to 10 (completely interferes).

RESULTS

The median NRS pain scores with movement were 2 (IQR, 0-5) on POD 1, 5 (IQR, 3-6) on POD 3, and the pain score was 3 (IQR, 1-5) on POD 14. Median total opioid use (converted to oral morphine equivalents) was 16 mg (4-50 mg) for the first 24 hours, 30 mg (8-63 mg) for the third, and 0 mg (0-20 mg) by the eighth 24-hour period, while the most frequent number of activations of the intravenous patient-controlled analgesia device was 0. Median PainOut scores on POD 1 and POD 14 for sleep interference, nausea, drowsiness and itching were 0, and the median composite Opioid-Related Symptom Distress Scale score on day 1 was 0.3 (IQR, 0.1-0.5).

CONCLUSIONS

Clinicians using this protocol, which combines a long-acting, single-injection nerve block with multimodal analgesia, can inform TSA patients that their postoperative pain will likely be less than their preoperative pain, and that on average they will stop using opioids after 7 days. Future research could investigate what the individual components of this protocol contribute. Larger cohort studies or registries would document the incidence of rare complications. Randomized controlled trials could directly compare analgesic effectiveness and cost-benefits for this protocol versus alternative strategies, such as perineural catheters or liposomal bupivacaine. Perhaps most importantly, future studies could seek ways to further reduce peak pain and opioid usage on POD 2 and POD 3.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Designing and conducting proof-of-concept chronic pain analgesic clinical trials

Introduction:

The evolution of pain treatment is dependent on successful development and testing of interventions. Proof-of-concept (POC) studies bridge the gap between identification of a novel target and evaluation of the candidate intervention's efficacy within a pain model or the intended clinical pain population.

Methods:

This narrative review describes and evaluates clinical trial phases, specific POC pain trials, and approaches to patient profiling.

Results:

We describe common POC trial designs and their value and challenges, a mechanism-based approach, and statistical issues for consideration.

Conclusion:

Proof-of-concept trials provide initial evidence for target use in a specific population, the most appropriate dosing strategy, and duration of treatment. A significant goal in designing an informative and efficient POC study is to ensure that the study is safe and sufficiently sensitive to detect a preliminary efficacy signal (ie, a potentially valuable therapy). Proof-of-concept studies help avoid resources wasted on targets/molecules that are not likely to succeed. As such, the design of a successful POC trial requires careful consideration of the research objective, patient population, the particular intervention, and outcome(s) of interest. These trials provide the basis for future, larger-scale studies confirming efficacy, tolerability, side effects, and other associated risks.

A nationwide comparative analysis of medical complications in fibromyalgia patients following total knee arthroplasty

Background

Fibromyalgia is a disease primarily characterized by chronic widespread pain and associated symptoms of fatigue, mild cognitive impairment, and sleep disturbance. The condition affects 1% to 6% of the general population in the United States and is more commonly diagnosed in women (2:1 ratio). There is evidence to suggest that fibromyalgia patients may be more at risk of postoperative complications. The rate of total knee arthroplasties (TKAs) performed worldwide is escalating and thus it is expected that the proportion of fibromyalgia patients under orthopaedic care will increase accordingly. However, the literature on TKA outcomes in this subpopulation is limited. We assessed whether fibromyalgia patients have a higher likelihood of developing medical complications compared to a matched cohort of non-fibromyalgia patients following TKA. Specifically, we assessed the likelihood of developing (I) any medical complication and (II) specific medical complications.

Methods

Using the Medicare Standard Analytical Files of the PearlDiver supercomputer, patients who underwent a TKA between 2005 and 2014 were queried. Propensity score matching was used to match patients with and without fibromyalgia in a 1:1 ratio based on age, sex, and the Charlson Comorbidity Index (CCI). A total cohort of 305,510 patients (female =242,198; male =59,810; and unknown =3,502) with (n=152,755) and without fibromyalgia (n=152,755) was identified. Statistical analyses involved the calculation of odds ratios, 95% confidence intervals (95% CI), and P values (<0.05) were utilized to evaluate the occurrence of any and specific medical complications.

Results

Compared to a matched cohort of non-fibromyalgia patients, fibromyalgia patients had increased odds of developing any medical complication following TKA [odds ratio (OR): 1.95, 95% CI: 1.86-2.04, P<0.001]. Furthermore, compared to a matched cohort, these patients had significantly greater odds of developing urinary tract infections (OR: 2.08, 95% CI: 1.89-2.29, P<0.001), acute post-hemorrhagic anemia (OR: 1.56, 95% CI: 1.41-1.73, P<0.001), thoracic or lumbosacral neuritis or radiculitis (OR: 5.85, 95% CI: 4.82-7.10, P<0.001), shortness of breath (OR: 3.02, 95% CI: 2.60-3.51, P<0.001), other diseases of lung not elsewhere classified (OR: 2.32, 95% CI: 1.77-3.03, P<0.001), other respiratory abnormalities (OR: 3.49, 95% CI: 2.87-4.24, P<0.001), transfusion of packed cells (OR: 1.69, 95% CI: 1.36-2.10, P<0.001), pneumonia (OR: 2.17, 95% CI: 1.71-2.76, P<0.001), acute kidney failure (OR: 1.27, 95% CI: 1.02-1.57, P<0.05), and neuralgia neuritis and radiculitis (OR: 5.29, 95% CI: 3.53-7.92, P<0.001).

Conclusions

As the number of fibromyalgia patients under orthopaedic care is expected to rise, it is imperative that the TKA outcomes of these patients are tracked in order to provide optimal patient care. This study identified fibromyalgia as a risk factor for a number of medical complications following TKA. Orthopaedic surgeons must be aware of the potential for poor TKA outcomes among these patients and should provide them with appropriate medical care and pre-operative guidance.

Self-reported cumulative medical opioid exposure and subjective responses on first use of opioids predict analgesic and subjective responses to placebo-controlled opioid administration

BACKGROUND AND OBJECTIVES

To expand the evidence base needed to enable personalized pain medicine, we evaluated whether self-reported cumulative exposure to medical opioids and subjective responses on first opioid use predicted responses to placebo-controlled opioid administration.

METHODS

In study 1, a survey assessing cumulative medical opioid exposure and subjective responses on first opioid use was created (History of Opioid Medical Exposure (HOME)) and psychometric features documented in a general sample of 307 working adults. In study 2, 49 patients with chronic low back pain completed the HOME and subsequently rated back pain intensity and subjective opioid effects four times after receiving saline placebo or intravenous morphine (four incremental doses) in two separate double-blinded laboratory sessions. Placebo-controlled morphine effects were derived for all outcomes.

RESULTS

Two HOME subscales were supported: cumulative opioid exposure and euphoric response, both demonstrating high test-retest reliability (Intraclass Correlation Coefficients > 0.93) and adequate internal consistency (Revelle's Omega Total = 0.73-0.77). In study 2, higher cumulative opioid exposure scores were associated with significantly greater morphine-related reductions in back pain intensity (p=0.02), but not with subjective drug effects. Higher euphoric response subscale scores were associated with significantly lower overall perceived morphine effect (p=0.003), less sedation (p=0.04), greater euphoria (p=0.03) and greater desire to take morphine again (p=0.02).

DISCUSSION

Self-reports of past exposure and responses to medical opioid analgesics may have utility for predicting subsequent analgesic responses and subjective effects. Further research is needed to establish the potential clinical and research utility of the HOME.

TRIAL REGISTRATION NUMBER

NCT02469077.