Aline Boulanger

Chronic Pain in Canada: Have We Improved Our Management of Chronic Noncancer Pain?

BACKGROUND Chronic noncancer pain (CNCP) is a global issue, not only affecting individual suffering, but also impacting the delivery of health care and the strength of local economies. OBJECTIVES The current study (the Canadian Chronic Pain Study II [CCPSII]) was designed to assess any changes in the prevalence and treatment of CNCP, as well as in attitudes toward the use of strong analgesics, compared with a 2001 study (the CCPSI), and to provide a snapshot of the current standards of care for pain management in Canada. METHODS Standard, computer-assisted telephone interview survey methodology was applied in two segments, ie, a general population survey and a survey targeting randomly selected primary care physicians (PCPs) who treat moderate to severe CNCP. RESULTS AND DISCUSSION The patient-reported prevalence of CNCP within Canada has not markedly changed since 2001 but the duration of suffering has decreased. There have been minor changes in regional distribution and generally more patients receive medical treatment, which includes prescription analgesics. Physicians continue to demonstrate opiophobia in their prescribing practices; however, although this is lessened relating to addiction, abuse remains an important concern to PCPs. Canadian PCPs, in general, are implementing standard assessments, treatment approaches, evaluation of treatment success and tools to prevent abuse and diversion, in accordance with guidelines from the Canadian Pain Society and other pain societies globally, although there remains room for improvement and standardization.

Buprenorphine transdermal system in adults with chronic low back pain: A randomized, double-blind, placebo-controlled crossover study, followed by an open-label extension phase

BACKGROUND Buprenorphine is a mixed-activity, partial mu-opioid agonist. Its lipid solubility makes it well suited for transdermal administration. OBJECTIVE This study assessed the efficacy and safety profile of a 7-day buprenorphine transdermal system (BTDS) in adult (age >18 years) patients with moderate to severe chronic low back pain previously treated with > or =1 tablet daily of an opioid analgesic. METHODS This was a randomized, double-blind, placebo-controlled crossover study, followed by an open-label extension phase. After a 2- to 7-day washout of previous opioid therapy, eligible patients were randomized to receive BTDS 10 microg/h or matching placebo patches. The dose was titrated weekly using 10- and 20-microg/h patches (maximum, 40 microg/h) based on efficacy and tolerability. After 4 weeks, patients crossed over to the alternative treatment for another 4 weeks. Patients who completed the double-blind study were eligible to enter the 6-month open-label phase. Rescue analgesia was provided as acetaminophen 325 mg to be taken as 1 or 2 tablets every 4 to 6 hours as needed. The primary outcome assessments were daily pain intensity, measured on a 100-mm visual analog scale (VAS), from no pain to excruciating pain, and a 5-point ordinal scale, from 0 = none to 4 = excruciating. Secondary outcome assessments included the Pain and Sleep Questionnaire (100-mm VAS, from never to always), Pain Disability Index (ordinal scale, from 0 = no disability to 11 = total disability), Quebec Back Pain Disability Scale (categorical scale, from 0 = no difficulty to 5 = unable to do), and the 36-item Short Form Health Survey (SF-36). Patients and investigators assessed overall treatment effectiveness at the end of each phase; they assessed treatment preference at the end of double-blind treatment. After implementation of a precautionary amendment, the QTc interval was measured 3 to 4 days after randomization and after any dose adjustment. All assessments performed during the double-blind phase were also performed every 2 months during the open-label extension. Adverse events were collected by non-directed questioning throughout the study. RESULTS Of 78 randomized patients, 52 (66.7%) completed at least 2 consecutive weeks of treatment in each study phase without major protocol violations (per-protocol [PP] population: 32 women, 20 men; mean [SD] age, 51.3 [11.4] years; mean weight, 85.5 [19.5] kg; 94% white, 4% black, 2% other). The mean (SD) dose of study medication during the last week of treatment was 29.8 (12.1) microg/h for BTDS and 32.9 (10.7) microg/h for placebo (P = NS). During the last week of treatment, BTDS was associated with significantly lower mean (SD) pain intensity scores compared with placebo on both the VAS (45.3 [21.3] vs 53.1 [24.3] mm, respectively; P = 0.022) and the 5-point ordinal scale (1.9 [0.7] vs 2.2 [0.8]; P = 0.044). The overall Pain and Sleep score was significantly lower with BTDS than with placebo (177.6 [125.5] vs 232.9 [131.9]; P = 0.027). There were no treatment differences on the Pain Disability Index, Quebec Back Pain Disability Scale, or SF-36; however, BTDS was associated with significant improvements compared with placebo on 2 individual Quebec Back Pain Disability Scale items (get out of bed: P = 0.042; sit in a chair for several hours: P = 0.022). Of the 48 patients/physicians in the PP population who rated the effectiveness of treatment, 64.6% of patients (n = 31) rated BTDS moderately or highly effective, as did 62.5% of investigators (n = 30). Among the 50 patients in the PP population who answered the preference question, 66.0% of patients (n = 33) preferred the phase in which they received BTDS and 24.0% (n = 12) preferred the phase in which they received placebo (P = 0.001), with the remainder having no preference; among investigators, 60.0% (n = 30) and 28.0% (n = 14) preferred the BTDS and placebo phases, respectively (P = 0.008), with the remainder having no preference. The mean placebo-adjusted change from baseline in the QTc interval ranged from -0.8 to +3.8 milliseconds (P = NS). BTDS treatment was associated with a significantly higher frequency of nausea (P < 0.001), dizziness (P < 0.001), vomiting (P = 0.008), somnolence (P = 0.020), and dry mouth (P = 0.003), but not constipation. Of the 49 patients completing 8 weeks of double-blind treatment, 40 (81.6%) entered the 6-month, open-label extension study and 27 completed it. Improvements in pain scores achieved during the double-blind phase were maintained in these patients. CONCLUSIONS In the 8-week, double-blind portion of this study, BTDS 10 to 40 microg/h was effective compared with placebo in the management of chronic, moderate to severe low back pain in patients who had previously received opioids. The improvements in pain scores were sustained throughout the 6-month, open-label extension. (Current Controlled Trials identification number: ISRCTN 06013881).

Successful use of methadone in the treatment of chronic neuropathic pain arising from burn injuries: a case-study

Methadone is used increasingly as a second-line opioid in the management of cancer pain refractory to conventional opioids. Recent case studies suggest that its use as an analgesic could be extended to non-cancer pain, especially neuropathic pain. The present case study reports, for the first time, the efficacy of methadone in a burn patient experiencing neuropathic pain in his healed wounds. The patient sustained extensive (55% total body surface area) chemical burns and developed chronic burning sensations, particularly in the lower limbs where skin grafting had been performed. Conventional pharmacotherapies against neuropathic pain were attempted to control pain for over 5 years. The agents used included long- and short-acting opioids, amitriptyline, clonazepam, and gabapentin, but they all failed to relieve the pain. When methadone (5 mg every 12 h) was introduced, it significantly alleviated the patients pain within a few days of administration. The patient has now been taking methadone (15 mg every 12 h) for 10 months and reports that the opioid caused 70% pain relief and a 55% amelioration in his quality of life. Although these results are based on a case report, they suggest that a switch to methadone might be useful in some burn patients who have developed chronic neuropathic pain unrelieved by conventional pharmacotherapies. Methadone, however, needs to be titrated with vigilance and thus should be administered by a physician experienced with its use in the treatment of chronic pain.

Management of chronic neuropathic pain with methadone: a review of 13 cases.

The synthetic opioid methadone has generated much interest in recent years among clinicians involved in the management of intractable chronic cancer pain. Its use as an analgesic is starting to extend to the treatment of noncancer pain, particularly neuropathic pain. Unfortunately, the evidence for its use in the management of neuropathic pain is limited to a few case studies. We examined retrospectively during a 12-month study period the clinical response of all 13 patients at our pain clinic who were prescribed methadone in an attempt to control neuropathic pain resistant to conventional analgesics. A questionnaire was also administered to the 9 patients who continued to take methadone at 12 months posttreatment. A total of 4 patients (31%) discontinued it by the end of the 12-month study period. Patients discontinued methadone due to the absence of pain relief and due to various intractable, undesirable side effects. Somnolence was the most common adverse effect reported, followed by nausea, constipation, and vomiting. All patients took coanalgesics (eg, amitriptyline, gabapentin) or other analgesics (eg, morphine, nonsteroidal anti-inflammatory drugs) during methadone treatment to control pain. The 9 patients who continued to take methadone at 12 months reported experiencing on average 43% pain relief (range 0-80%), 47% improvement in quality of life (range 0-100%), and 30% improvement in quality of sleep (range 0-60%). Methadone was effective at relieving pain and ameliorating quality of life and sleep in 62% of patients. These findings suggest that methadone can offer an acceptable success rate for the treatment of neuropathic pain. Prospective randomized, placebo-controlled studies are now needed to examine more rigorously the benefits of methadone for this type of pain.

Intrathecal Morphine after Cardiac Surgery

OBJECTIVE: To assess whether intrathecal (IT) analgesia facilitates early extubation and provides superior pain control after cardiac surgery compared with patient-controlled analgesia (PCA) or nurse-administered SC injections. METHODS: Sixty-two patients undergoing elective cardiac surgery participated in this prospective, randomized, partly-blinded study. Perioperative care was standardized, and patients were assigned to receive IT morphine (ITM group) followed by PCA, IT placebo (ITP group) followed by PCA, or SC injections of morphine every 4 hours as needed (SC group). Rating scales and questionnaires were used to assess clinical outcomes. RESULTS: ITM did not favor earlier extubation, and there was even a tendency for longer extubation × in the ITM group compared with the ITP and SC groups. Pain scores, adverse effects, postoperative recovery, and patient satisfaction were also comparable in the 3 groups. CONCLUSIONS: Considering that the administration of IT morphine is more costly and can be riskier than conventional analgesic regimens, we conclude that its use is not indicated in patients undergoing cardiac surgery if early extubation is planned.

Further validation of the BDI-II among people with chronic pain originating from musculoskeletal disorders.

ObjectiveOne criticism of the BDI-II for assessing depressive symptoms in people experiencing chronic pain has been the potential overlap between the physical or psychological origins of some of the symptoms. Furthermore, previous studies have reported both two-factor and three-factor solutions, so that the factor solution of the instrument in this population remains unclear. The main objective of the present study was to validate the BDI-II with a chronic pain population experiencing musculoskeletal disorders. Three specific objectives were: (1) to modify the BDI-II for people with musculoskeletal disorders by adding sub-questions to better identify the perceived cause of the depressive symptoms, (2) to assess the validity and reliability of this modified version of the BDI-II, and (3) to explore the perceptions of the causes/origins of symptoms reported on the BDI-II. Results of the confirmatory factor analysis supported the presence of three dimensions within the BDI- : Cognitive, Affective and Somatic. MethodsA total of 206 participants experiencing chronic pain answered a modified version of the BDI-II, the CES-D and a sociodemographic questionnaire. ResultsResults confirmed the three-dimensional factorial structure of the BDI for this population. Overall, participants experienced higher levels of somatic symptoms compared to symptoms belonging to other dimensions. The percentages of answers to the sub-questions were also similarly distributed between “pain”, and “pain and state of mind”, regardless of the dimension. DiscussionThe importance of assessing somatic symptoms of depression in pain patients and of thoroughly examining the underlying perceived cause of symptoms, regardless of the dimension, are discussed.

The Canadian STOP-PAIN project: the burden of chronic pain-does sex really matter?

Objectives:The Canadian STOP-PAIN Project assessed the human and economic burden of chronic pain (CP) in individuals on waitlists of Canadian multidisciplinary pain treatment facilities. This article focuses on sex differences. Objectives were to (1) determine the pain characteristics and related biopsychosocial factors that best differentiated women and men with CP; and (2) examine whether public and private costs associated with CP differed according to sex. Materials and Methods:Sample consisted of 441 women and 287 men who were evaluated using self-administered questionnaires and a structured interview protocol. A subsample (233 women and 137 men) recorded all pain-related expenditures in a comprehensive diary over 3 months. Results:Results revealed that the burden of illness associated with CP was comparable in both sexes for average and worst pain intensity, pain impact on daily living, quality of life, and psychological well-being. The same was true for pain-related costs. The results of a hierarchical logistic regression analysis, in which sex was treated as the dependent variable, showed that factors that differentiated men and women were: work status, certain circumstances surrounding pain onset, present pain intensity, intake of particular types of pain medication, use of certain pain management strategies, pain beliefs, and utilization of particular health care resources. Discussion:This study suggests that women and men who are referred to multidisciplinary pain treatment facilities do not differ significantly in terms of their pain-related experience. However, the aspects that differ may warrant further clinical attention when assessing and managing pain.

Rapid induction sequence with vecuronium: should we intubate after 60 or 90 seconds?

The purpose of the study was to determine intubating conditions after administration of either succinylcholine or vecuronium in a rapid induction sequence. Patients received either succinylcholine 1.5 mg· kg− 1 (Groups I and II) after d-tubocurarine 0.05 mg · kg− 1 four minutes earlier, or vecuronium (Groups III and IV) in an initial dose of 0.01 mg · kg− 1 followed four minutes later by 0.1 mg · kg− 1. In Groups I and III an apnoeic delay of one minute was allowed before intubation whereas in Groups II and IV the delay was 90 sec. There was no significant difference in intubating conditions between Groups I and IV. Intubating conditions in Group III (vecuronium — delay of one minute were statistically worse than in any of the three other groups. A delay of 90 sec after succinylcholine improved intubating conditions in male patients. Considering that intubating conditions obtained after 90 sec in patients given a priming sequence with vecuronium (Group IV) were not different from those obtained 60 sec after succinylcholine (Group I), the authors conclude that vecuronium is an acceptable alternative for rapid tracheal intubation. In the doses used in this study, intubating conditions 60 sec after vecuronium were unacceptable for rapid induction of anaesthesia.RésuméL’étude avait pour but de vérifier les conditions d’intubation lors d’une induction à séquence rapide utilisant la succinylcholine ou le vécuronium comme myorelaxant. Les patients des Groupes I et II recevaient un pré-traitement avec de la d-tubocurarine 0,05mg · kg− 1 suivi quatre minutes plus tard de succinylcholine 1.5 mg · kg− 1. Les patients des Groupes III et IV recevaient une dose d’amorce de vécuronium de 0,01 mg · kg− 1, suivie quatre minutes plus tard d’une dose de 0,1 mg · kg− 1. Le délai entre l’administration du myorelaxant et l’intubation était de une minute dans les Groupes I et III, alors que dans les Groupes II et IV ce délai était de 90 sec. Il n’y avait pas de différence statistiquement significative dans les conditions d’intubation entre les Groupes I et IV. Statistiquement, les moins bonnes conditions d’intubation se sont retrouvées chez les patients du Groupe III (vécuronium — délai d’une minute). Un délai de 90 sec après l’administration de la succinylcholine améliorait significativement les conditions d’intubation chez les patients de sexe masculin. Etant donné que les conditions d’intubation des patients du groupe IV (vécruonium-délai de 90 sec) n’étaient pas differentes de celles des patients du Groupe I (succinylcholine-délai d’une minute), les auteurs concluent que le vécuronium constitue une alternative valable à la succinylcholine comme myorelaxant pour l’intubation à séquence rapide. Les conditions d’intubation 60 sec après l’administration de vécuronium aux doses utilisées dans cette étude étaient inacceptables.

Accuracy of Self-reported Prescribed Analgesic Medication Use: Linkage Between the Quebec Pain Registry and the Quebec Administrative Prescription Claims Databases.

Objectives:The validity of studies conducted with patient registries depends on the accuracy of the self-reported clinical data. As of now, studies about the validity of self-reported use of analgesics among chronic pain (CP) populations are scarce. The objective of this study was to assess the accuracy of self-reported prescribed analgesic medication use. This was attained by comparing the data collected in the Quebec Pain Registry (QPR) database to those contained in the Quebec administrative prescription claims database (Régie de l’assurance maladie du Québec [RAMQ]). Methods:To achieve the linkage between the QPR and the RAMQ databases, the first 1285 patients who were consecutively enrolled in the QPR between October 31, 2008 and January 27, 2010 were contacted by mail and invited to participate in a study in which they had to provide their unique RAMQ health insurance number. Using RAMQ prescription claims as the reference standard, &kgr; coefficients, sensitivity, specificity, and their respective 95% confidence intervals were calculated for each therapeutic class of prescribed analgesic drugs that the participants reported taking currently and in the past 12 months. Results:A total of 569 QPR patients responded to the postal mailing, provided their unique health insurance number, and gave informed consent for the linkage (response proportion=44%). Complete RAMQ prescription claims over the 12 months before patient enrollment into the QPR were available for 272 patients, who constituted our validated study population. Regarding current self-reported prescribed analgesic use, &kgr; coefficients measuring agreement between the 2 sources of information ranged from 0.66 to 0.78 for COX-2-selective nonsteroidal anti-inflammatory drugs, anticonvulsants, antidepressants, skeletal muscle relaxants, synthetic cannabinoids, opiate agonists/partial agonists/antagonists, and antimigraine agents therapeutic classes. For the past 12-month self-reported prescribed analgesic use, QPR patients were less accurate regarding anticonvulsants (&kgr;=0.59), opiate agonists/partial agonists/antagonists (&kgr;=0.57), and antimigraine agents use (&kgr;=0.39). Discussion:Information about current prescribed analgesic medication use as reported by CP patients was accurate for the main therapeutic drug classes used in CP management. Accuracy of the past year self-reported prescribed analgesic use was somewhat lower but only for certain classes of medication, the concordance being good on all the others.

Early Factors Associated with the Development of Chronic Pain in Trauma Patients

Objective To identify factors, available at the time of trauma admission, associated with the development of chronic pain to allow testing of preventive approaches. Methods In a retrospective observational cohort study, we included all patients ≥ 18 years old admitted for injury in 57 adult trauma centers in the province of Quebec (Canada) between 2004 and 2014. Chronic pain was defined as follows: treated in a chronic pain clinic, diagnosed with chronic pain, or received at least 2 prescriptions of chronic pain medications 3 to 12 months postinjury. Results A total of 95,134 patients were retained for analysis. Mean age was 59.8 years (±21.7), and 52% were men. The causes of trauma were falls (63%) and motor vehicle accidents (22%). We identified 14,518 patients (15.3%; 95% CI: 15.1–15.5) who developed chronic pain. After controlling for confounding factors, the variables associated with chronic pain were spinal cord injury (OR = 3.9; 95% CI: 3.4–4.6), disc-vertebra trauma (OR = 1.6; 95% CI: 1.5–1.7), history of alcoholism (OR = 1.4; 95% CI: 1.2–1.7), history of anxiety (OR = 1.4; 95% CI: 1.2–1.5), history of depression (OR = 1.3; 95% CI: 1.1–1.4), and being female (OR = 1.3; 95% CI: 1.2–1.3). The area under the receiving operating characteristic curve derived from the model was 0.80. Conclusions We identified risk factors present on hospital admission that can predict trauma patients who will develop chronic pain. These factors should be prospectively validated.