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Chronic pain and substance use disorders are serious conditions that are prevalent among homeless populations. The aim of this study was to examine the association between chronic pain and substance use among individuals experiencing homelessness and mental illness. We analyzed cross-sectional data from two sites of the At Home/Chez Soi study (Vancouver and Toronto) using bivariate statistics and multivariate logistic regression. Substance use and chronic pain parameters were assessed with the Maudsley Addiction Profile and purpose-designed short instruments. The sample comprised 828 participants. Mean age was 42.4 years and 54% reported chronic pain. In bivariate analysis, chronic pain was significantly associated with use of opioids and stimulants, daily substance use, polysubstance use and injecting as route of administration. In multivariate analysis, only daily substance use (OR: 1.46, 95% CI: 1.02-2.09) and injecting (OR: 1.81, 95% CI: 1.08-3.05) remained as significant associated factors, whereas neither use of opioids nor use of stimulants specifically were significantly associated with chronic pain. Among participants with chronic pain, daily substance users (50% vs. 22%, < 0.001) and injectors (66% vs. 24%, < 0.001) were more likely to use non-prescribed medication for pain. Participants with daily substance use were less likely to receive professional treatment (52% vs. 64%, = 0.017) and prescribed pain medication (42% vs. 54%, = 0.023). Our findings suggest an association of chronic pain with patterns related to severity of substance use rather than to specific substance use in homeless persons with mental illness. Interventions aiming at prevention and treatment of chronic pain in this population should consider severity of substance use and associated risk behavior over use of specific substances.
Learn More >Chronic exertional compartment syndrome (CECS) is a condition occurring most frequently in the lower limbs and often requires corrective surgery to alleviate symptoms. Amongst military personnel, the success rates of this surgery can be as low as 20%, presenting a challenge in determining whether surgery is worthwhile. In this study, the data of 132 fasciotomies for CECS was analysed and using combinatorial feature selection methods, coupled with input from clinicians, identified a set of key clinical features contributing to the occupational outcomes of surgery. Features were utilised to develop a machine learning model for predicting return-to-work outcomes 12-months post-surgery. An AUC of 0.85 ± 0.08 was achieved using a linear-SVM, trained using 6 features (height, mean arterial pressure, pre-surgical score on the exercise-induced leg pain questionnaire, time from initial presentation to surgery, and whether a patient had received a prior surgery for CECS). To facilitate trust and transparency, interrogation strategies were used to identify reasons why certain patients were misclassified, using instance hardness measures. Model interrogation revealed that patient difficulty was associated with an overlap in the clinical characteristics of surgical outcomes, which was best handled by XGBoost and SVM-based models. The methodology was compiled into a machine learning framework, termed AITIA, which can be applied to other clinical problems. AITIA extends the typical machine learning pipeline, integrating the proposed interrogation strategy, allowing to user to reason and decide whether to trust the developed model based on the sensibility of its decision-making.
Learn More >Greater trochanteric pain syndrome (GTPS) is a musculoskeletal condition which can cause disability and reduce quality of life. However, limited evidence is available on the long-term outcomes of people with GTPS. Our aims were to determine the long-term prevalence of GTPS; to calculate the proportion of people with GTPS who had developed hip osteoarthritis (OA); and to determine the level of function and quality of life, 11-years after initial GTPS diagnosis.
Learn More >Fremanezumab, a fully humanized monoclonal antibody (IgG2Δa) that selectively targets calcitonin gene-related peptide (CGRP), is approved for migraine prevention in adults. Real-world data on the effectiveness of fremanezumab are limited. This retrospective, observational cohort study assessed patient-reported migraine symptoms, health care resource utilization (HCRU), and direct medical costs before and after fremanezumab treatment initiation.
Learn More >Migraine with aura may respond differently to therapies than migraine without aura. Individuals with migraine with aura have an elevated vascular risk, necessitating a safety assessment of migraine preventive treatments in this patient subgroup.
Learn More >Sumatriptan was introduced in 1983, as the first of the triptans, selective 5-hydroxytryptamine (5-HT ) receptor agonists, to treat moderate to severe migraine. Migraine predominates in females. Although there have been reports of sex differences in migraine-associated features and pharmacokinetics (PKs) of some triptans, sex differences in the PKs of oral sumatriptan have never been evaluated in Korean. We conducted this study of oral sumatriptan to assess the sex differences in Korean population. Thirty-eight healthy Korean subjects who participated in two separate clinical studies receiving a single oral dose of 50 mg sumatriptan with the same protocols were included in this analysis. A total of 532 sumatriptan concentration observations were used for a population PK modeling. Validation of final population PK model of sumatriptan was performed using bootstrap and visual predictive check. The PK profile of oral sumatriptan was adequately described by a one-compartmental model with combined transit compartment model and a first-order absorption. The covariate analysis showed that the clearance of oral sumatriptan was significantly higher in males than in females (male: 444 L/h, female: 281 L/h). Our results showed that there were sex differences in the clearance of oral sumatriptan. These results encourage further studies to establish the sumatriptan pharmacokinetic-pharmacodynamic (PK-PD) model considering sex-related PK differences, which may help to determine optimal dosing regimens for effective treatment of migraine in males and females. This article is protected by copyright. All rights reserved.
Learn More >Low-grade inflammation is a possible contributing factor in the development and persistence of chronic primary pain syndromes. Related to inflammatory activity is sickness behavior, a set of behavioral responses including increased pain sensitivity, fatigue, malaise, fever, loss of appetite, as well as depressive behavior and anhedonia. To capture these behavioral responses and their relation to longstanding pain, psychometrically sound self-report questionnaires are needed. The Sickness Questionnaire (SicknessQ) was developed to assess self-reported sickness behavior based on studies on acute immune activation while maintaining relevance for persistent conditions. The aim of the current study was to evaluate aspects of the validity and reliability of the SicknessQ in a Swedish sample of persons with longstanding pain.
Learn More >Headache disorders are disabling, with major consequences for productivity, yet the literature is silent on the relationship between headache-attributed disability and lost productivity, often erroneously regarding the two as synonymous. We evaluated the relationship empirically, having earlier found that investment in structured headache services would be cost saving, not merely cost-effective, if reductions in headache-attributed disability led to > 20% pro rata recovery of lost productivity.
Learn More >Migraine prevalence is age and sex dependent, predominating in women in early and middle adulthood; however, migraine also represents a substantial burden for men and adults of all ages. Thus, understanding this burden and the efficacy of migraine preventive medications in both sexes and across age groups is critical. The randomized, placebo-controlled, double-blind, phase 3b FOCUS study demonstrated the safety and efficacy of fremanezumab, a fully humanized monoclonal antibody (IgG2∆a) that selectively targets calcitonin gene-related peptide as a migraine preventive treatment for individuals with migraine and prior inadequate response to 2 to 4 migraine preventive medication classes. Here, we assessed the efficacy of fremanezumab in participants from FOCUS subgrouped by age (18-45 years and > 45 years) and sex.
Learn More >There is a lack of clinically relevant measures for quantification of maladaptive mechanisms of the nociceptive system leading to chronic pain. Recently, we developed a method that tracks nociceptive detection thresholds (NDTs) using intraepidermal electrical stimulation. In this study, we explored the feasibility of using this NDT method in patients with persistent spinal pain syndrome type 2 (PSPS-T2) and its potential to enable observation of altered nociceptive processing induced by dorsal root ganglion (DRG) stimulation. In addition, we compared NDTs with quantitative sensory testing (QST) measurements and numeric rating scale (NRS).
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