Opioid use in rheumatoid arthritis: trends, efficacy, safety, and best practices

Reproductive health and rheumatoid arthritis

INTRODUCTION

The prevalence of Rheumatoid Arthritis (RA) has been steadily increasing over the last thirty years, particularly among women. Due to the conflicting results of various studies on the link between rheumatoid arthritis and reproductive health, we have undertaken this study to explore their relationship.

METHODS

This cross-sectional study utilized primary data from5557 women involved in the Fasa Persian Cohort in the years 2013 to 2018. The study examined the frequency of RA and its association with various factors related to reproductive health, including age at first pregnancy, number of alive children, history of abortion, and infertility. SPSS software was utilized for data analysis, with the significance level set at p < 0.05.

RESULTS

5557 women with an average age of 48.6 ± 9.5 years participated. Of these women, 7.2% were diagnosed with rheumatoid disease, with an average onset age of 38.2 ± 15.2. The study did not find a significant correlation between RA and factors such as number of pregnancies, age at first pregnancy, duration of breastfeeding and number of children.

CONCLUSION

The study suggests that the experience of RA is independent of gynecological, obstetric factors, or reproductive life. This finding may provide reassurance to women affected by RA.

Clinician Perspectives on Opioid Treatment Agreements: A Qualitative Analysis of Focus Groups

BACKGROUND

Patients with chronic pain face significant barriers in finding clinicians to manage long-term opioid therapy (LTOT). For patients on LTOT, it is increasingly common to have them sign opioid treatment agreements (OTAs). OTAs enumerate the risks of opioids, as informed consent documents would, but also the requirements that patients must meet to receive LTOT. While there has been an ongoing scholarly discussion about the practical and ethical implications of OTA use in the abstract, little is known about how clinicians use them and if OTAs themselves modify clinician prescribing practices.

OBJECTIVE

To determine how clinicians use OTAs and the potential impacts of OTAs on opioid prescribing.

DESIGN

We conducted qualitative analysis of four focus groups of clinicians from a large Midwestern academic medical center. Groups were organized according to self-identified prescribing patterns: two groups for clinicians who identified as prescribers of LTOT, and two who did not.

PARTICIPANTS

17 clinicians from General Internal Medicine, Family Medicine, and Palliative Care were recruited using purposive, convenience sampling.

APPROACH

Discussions were recorded, transcribed, and analyzed for themes using reflexive thematic analysis by a multidisciplinary team.

KEY RESULTS

Our analysis identified three main themes: (1) OTAs did not influence clinicians' decisions whether to use LTOT generally but did shape clinical decision-making for individual patients; (2) clinicians feel OTAs intensify the power they have over patients, though this was not uniformly judged as harmful; (3) there is a potential misalignment between the intended purposes of OTAs and their implementation.

CONCLUSION

This study reveals a complicated relationship between OTAs and access to pain management. While OTAs seem not to impact the clinicians' decisions about whether to use LTOT generally, they do sometimes influence prescribing decisions for individual patients. Clinicians shared complex views about OTAs' purposes, which shows the need for more clarity about how OTAs could be used to promote shared decision-making, joint accountability, informed consent, and patient education.

Opioid use surrounding diagnosis and follow-up in patients with ankylosing spondylitis, psoriatic arthritis, and rheumatoid arthritis: Results from US claims databases

OBJECTIVE

To describe patients' use of opioids in the year preceding and year following new diagnosis of ankylosing spondylitis (AS), psoriatic arthritis (PsA), or rheumatoid arthritis (RA), compared with patients without the/se diseases.

METHODS

This study used US IBM® MarketScan® Commercial Claims and Encounters (CCAE) and Medicaid data and included three cohorts, comprised of incident cases of AS, PsA, or RA (2010-2017). Three matched comparator patients (without the incident disease) were selected for each patient within the disease cohort. Opioid use and appropriate treatment exposure (as defined by US guideline recommendations) in the 12-month baseline and follow-up periods were evaluated using descriptive analyses.

RESULTS

Prevalence of claims for opioids was higher for disease cohorts vs. comparators in CCAE; 36.4% of patients with AS, 29.5% with PsA, and 44.4% with RA did not have any claim for guideline-appropriate therapy in follow-up. Prevalence of claims for opioids was also higher for disease cohorts vs. comparators in Medicaid; 30.6% of patients with AS, 36.6% with PsA, and 65.4% with RA did not have any claim for guideline-appropriate therapy in follow-up.

CONCLUSIONS

In patients with AS, PsA, or RA, there was high reliance on opioids at and around the time of diagnosis. Significant proportions of patients were not on appropriate treatment as defined by professional society post-diagnosis guidelines; this discordance between actual patient therapies and treatment recommendations may suggest a need for better awareness of appropriate pain management and treatment strategies in rheumatic diseases. Key Points • This study analysed opioid use among patients with ankylosing spondylitis (AS), psoriatic arthritis (PsA), or rheumatoid arthritis (RA), and adds to current knowledge by expanding beyond assessment of opioid use at diagnosis, to the year before and after diagnosis. • Opioid use was found to be highly prevalent in AS, PsA, and RA in the year prior to diagnosis and, interestingly, was still seen during the year after diagnosis. • Opioids are neither disease modifying, nor a targeted/recommended treatment for chronic autoimmune diseases. In addition to their association with significant economic costs, opioids are potentially hazardous and are not better than alternative treatments with superior safety profiles. • The reasons behind opioid prescribing patterns should be explored further to support movement to targeted therapies.

Association of Rheumatoid Arthritis with Opioid Pain Medication Overuse among Persons Exposed to the 9/11 World Trade Center Disaster

We examined the association of post-9/11 rheumatoid arthritis (RA) diagnosis with opioid pain medication overuse among enrollees in the World Trade Center Health Registry (WTCHR). Opioid overuse was defined as the self-reported intake of prescribed opioids at a higher dosage or more often than directed in the last 12 months on one of the two most recent WTCHR surveys (2015-2016, 2020-2021). Post-9/11 RA was ascertained through self-reports and subsequently validated following medical record release by the enrollees' physicians or medical records review. We excluded those with self-reported RA that was not validated by their physicians and those who did not report being prescribed opioid pain medication in the last 12 months. Multivariable log-binomial regression was conducted to examine the relationship between post-9/11 RA diagnosis and opioid pain medication overuse, adjusting for sociodemographic characteristics and 9/11-related posttraumatic stress disorder (PTSD) symptoms. Of the 10,196 study enrollees, 46 had confirmed post-9/11 RA. The post-9/11 RA patients were mostly females (69.6% vs. 37.7%), less frequently non-Hispanic White (58.7% vs. 73.2%) individuals, and less often had attained a higher level of education (76.1% vs. 84.4%) compared to those without post-9/11 RA. Opioid pain medication overuse was significantly associated with a post-9/11 RA diagnosis (Adjusted Risk Ratio: 2.13, 95% CI: 1.44-3.17). More research is needed to better understand the use and management of prescribed opioids among WTC-exposed individuals with RA.

Optimizing Medication Use in Older Adults With Rheumatic Musculoskeletal Diseases: Deprescribing as an Approach When Less May Be More

The world population is aging, and the rheumatology workforce must be prepared to care for medically complex older adults. We can learn from our colleagues and experts in geriatrics about how to best manage multimorbidity, polypharmacy, geriatric syndromes, and shifting priorities of older adults in the context of delivering care for rheumatic and musculoskeletal diseases (RMDs). Polypharmacy, a common occurrence in an aging population with multimorbidity, affects half of older adults with RMDs and is associated with increased risk of morbidity and mortality. In addition, potentially inappropriate medications that should be avoided under most circumstances is common in the RMD population. In recent years, deprescribing, known as the process of tapering, stopping, discontinuing, or withdrawing drugs, has been introduced as an approach to improve appropriate medication use among older adults and the outcomes that are important to them. As the rheumatology patient population ages globally, it is imperative to understand the burden of polypharmacy and the potential of deprescribing to improve medication use in older adults with RMDs. We encourage the rheumatology community to implement geriatric principles, when possible, as we move toward becoming an age-friendly health care specialty.

Frequency and Predictors of Opioid Use in Rheumatoid Arthritis and Seronegative Spondyloarthropathy Patients

BACKGROUND

Pain is one of the most challenging symptoms in patients with rheumatoid arthritis (RA) and spondyloarthropathies (SpAs), and pain relief is one of the top priorities for improving health-related quality of life. When medication therapy does not significantly reduce pain, chronic opioid consumption becomes more prominent in such patients. This study aimed to evaluate the state of opioid use in RA and SpA patients.

METHODS

This cross-sectional study was performed on 316 patients with RA and spondyloarthropathies (SpAs) from January to March 2014. The convenience sampling method was used to select the participants, and by obtaining verbal consent, everyone was given 15 minutes to complete a checklist independently. Demographic and opioid use data were evaluated in terms of opioid use and its predictors. In this regard, univariate and multivariate logistic regressions were used to evaluate the predictors of opioid consumption in patients. All analyses were conducted using SPSS 21 and the significance level was set at P<0.05.

FINDINGS

About 9.5% of all participants, including 8.8% of RA and 22.6% of SpA cases, were opioid abusers. In the first step of the analysis, it was observed that opioid abuse was significantly higher in men, married participants, urban residents, patients with no biological therapy, and patients with a negative family history of addiction. The most prevalent ways of drug abuse were smoking and ingestion. The results of univariate logistic regression analysis revealed SpA and other factors significantly increase the chance of opioid abuse. Furthermore, multivariate logistic regression analysis showed male gender (OR=10.4) and negative family history of addiction (OR=3.19) significantly affected addiction in RA and SpA patients with a 95% confidence interval.

CONCLUSION

Lack of suitable responsiveness to medication therapy to relieve pain, inconsistent pain evaluation, and shame of asking direct questions about addiction in RA and SpA patients may lead to opioid consumption in some cases. Seronegative SpA may make patients more prone to addiction. However, in this study, male gender and no family history of addiction were related to opioid abuse.

Long-term opioid use and mortality in patients with chronic non-cancer pain: Ten-year follow-up study in South Korea from 2010 through 2019

BACKGROUND

We aimed to investigate the prevalence and factors associated with long-term opioid use among patients with chronic non-cancer pain (CNCP).

METHODS

We extracted data from the National Health Insurance Service (NHIS) database in South Korea. As a nationwide database, the NHIS database contains information regarding all disease diagnoses and prescriptions for any drug and/or procedures. A total of 2.5% of adult patients (≥20 years of age) who were diagnosed with musculoskeletal diseases and CNCP from 2010 to 2019 were selected using a stratified random sampling technique and included in the analysis. Patients who were prescribed opioids continuously for ≥90 days were classified as long-term opioid users.

FINDINGS

A total of 19,645,161 patients with CNCP were included in the final analysis. The prevalence of long-term opioid use was 0.47% (95% confidence interval [CI]: 0.46%, 0.48%; 8421/1,808,043) in 2010, which gradually increased to 2.63% (95% CI: 2.61%, 2.66%; 49,846/1,892,913) in 2019. Among the 2010 cohort (n = 1,804,019), in multivariable logistic regression: old age, underlying disability, increased Charlson comorbidity index, use of benzodiazepine or Z-drug, rheumatoid arthritis, osteoarthritis, and low back pain were associated with an increased prevalence of long-term opioid use among patients with CNCP. In a multivariable Cox regression, the 10-year all-cause mortality in long-term opioid users was found to be 1·21-fold (hazard ratio: 1.21, 95% CI: 1.13, 1.31; P<0·001) higher than that in opioid-naive patients with CNCP.

INTERPRETATION

Long-term opioid use increased in patients with CNCP in South Korea from 2010 to 2019. Certain factors were potential risk factors for long-term opioid use. Moreover, long-term opioid use was associated with increased 10-year all-cause mortality among patients with CNCP.

FUNDING

None.

Pain and Opioid-Induced Gut Microbial Dysbiosis

Opioid-induced dysbiosis (OID) is a specific condition describing the consequences of opioid use on the bacterial composition of the gut. Opioids have been shown to affect the epithelial barrier in the gut and modulate inflammatory pathways, possibly mediating opioid tolerance or opioid-induced hyperalgesia; in combination, these allow the invasion and proliferation of non-native bacterial colonies. There is also evidence that the gut-brain axis is linked to the emotional and cognitive aspects of the brain with intestinal function, which can be a factor that affects mental health. For example, Mycobacterium, Escherichia coli and Clostridium difficile are linked to Irritable Bowel Disease; Lactobacillaceae and Enterococcacae have associations with Parkinson’s disease, and Alistipes has increased prevalence in depression. However, changes to the gut microbiome can be therapeutically influenced with treatments such as faecal microbiota transplantation, targeted antibiotic therapy and probiotics. There is also evidence of emerging therapies to combat OID. This review has collated evidence that shows that there are correlations between OID and depression, Parkinson’s Disease, infection, and more. Specifically, in pain management, targeting OID deserves specific investigations.

Pain Reduction in Rheumatoid Arthritis Patients Who Use Opioids: A Post Hoc Analysis of Phase 3 Trials of Baricitinib

Objective

Pain reduction with baricitinib was assessed in patients with rheumatoid arthritis (RA) who either used opioids or did not use opioids during three randomized, double‐blind phase 3 trials.

Methods

Analysis populations were as follows: i) baricitinib 4 mg once daily versus placebo groups integrated from RA‐BEAM (NCT01710358) for patients with inadequate response (IR) to methotrexate, RA‐BUILD (NCT01721057) with IR to conventional disease‐modifying antirheumatic drugs, and RA‐BEACON (NCT01721044) with IR to at least one tumor necrosis factor inhibitors; ii) baricitinib 2 mg versus placebo from RA‐BUILD and RA‐BEACON; and iii) adalimumab 40 mg every other week versus placebo from RA‐BEAM. Pain was measured by the Patient Assessment of Pain Visual Analog Scale. Analysis of covariance modeling assessed differences in pain reduction between treatments at each time point through Week 24, with an interaction term to test heterogeneous treatment effects across opioid users and nonusers.

Results

Baricitinib 4 mg had greater pain reduction versus placebo in opioid users and nonusers (P < 0.05) at all time points starting from Week 1; the pain reduction was similar between opioid users and nonusers. Baricitinib 2 mg had greater pain reduction versus placebo in opioid users and nonusers starting at Week 4. A significant difference in pain reduction was not observed for adalimumab versus placebo in the opioid users but was observed in nonusers at all time points.

Conclusion

Pain reduction was observed and was similar between opioid users and nonusers with baricitinib 2 mg and 4 mg but not adalimumab in this post hoc analysis.

Effect of Anti-Inflammatory Diets on Pain in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

Various nutritional therapies have been proposed in rheumatoid arthritis, particularly diets rich in ω-3 fatty acids, which may lead to eicosanoid reduction. Our aim was to investigate the effect of potentially anti-inflammatory diets (Mediterranean, vegetarian, vegan, ketogenic) on pain. The primary outcome was pain on a 10 cm visual analogue scale. Secondary outcomes were C-reactive protein levels, erythrocyte sedimentation rate, health assessment questionnaire, disease activity score 28, tender/swollen joint counts, weight, and body mass index. We searched MEDLINE (OVID), Embase (Elsevier), and CINAHL for studies published from database inception to 12 November 2021. Two authors independently assessed studies for inclusion, extracted study data, and assessed the risk of bias. We performed a meta-analysis with all eligible randomized controlled trials using RevMan 5. We used mean differences or standardized mean differences and the inverse variance method of pooling using a random-effects model. The search retrieved 564 unique publications, of which we included 12 in the systematic review and 7 in the meta-analysis. All studies had a high risk of bias and the evidence was very low. The main conclusion is that anti-inflammatory diets resulted in significantly lower pain than ordinary diets (-9.22 mm; 95% CI -14.15 to -4.29; p = 0.0002; 7 RCTs, 326 participants).

Pain Management Strategies in Rheumatoid Arthritis: A Narrative Review

Rheumatoid Arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation and progressive deterioration of the joints, which generates pain and stiffness. The origin of this pain is multifactorial, with inflammation, secondary osteoarthritis, as well as central and peripheral sensitization playing important roles in the development. Up to 90.4% of RA patients visit a health professional for severe pain, and despite new therapies and sophisticated treatments, there are a limited number of options for analgesic management. We conducted a narrative review using the Medline and Pubmed search engines for articles in English and Spanish between 2000 and 2021, with the keywords "pain," "rheumatoid arthritis," "non-steroidal anti-inflammatory drugs" (NSAIDs), "opioids," "glucocorticoids," "disease modifying antirheumatic drugs" (DMARDs), "neuromodulators," "antidepressants," and "cannabinoids." The articles describing epidemiology, pathophysiological considerations and current treatments were selected after a screening process carried out by the authors. It was found that DMARDs are the fundamental basis of treatment, since the main mechanism of pain in this entity is inflammation. Nonetheless, a significant number of patients continue to have pain despite optimal treatment. The available evidence for pain management in RA is scarce, however, medications such as NSAIDs, topical capsaicin, weak opioids, and treatments such as joint infiltrations or surgical management, play an important role in its management. We believe more research efforts are needed to optimize analgesic treatment recommendations, however, based on the current existing evidence, we propose a stepwise algorithm in order to properly approach these cases.

Key PointsRA is a systemic autoimmune disease characterized by chronic inflammation, in which the main symptom is pain.Pain in RA is multifactorial, with inflammation, secondary osteoarthritis, as well as central and peripheral sensitization playing determining roles.DMARDs are the mainstay of RA treatment, although many patients continue to experience pain despite optimal management.Medications such as glucocorticoids, NSAIDs, topical capsaicin, and weak opioids are key elements when achieving analgesia in RA.Other pharmacological groups such as neuromodulators, antidepressants, muscle relaxants and cannabinoids currently do not have enough evidence to be recommended.

A systematic scoping study exploring opioid use across a variety of disability conditions

BACKGROUND

Opioid use experiences among people with disability (PWD) as a group has not been clearly articulated in the current literature, despite links between pain and measures of disability.

OBJECTIVE

To conduct a systematic search and scoping study examining the characteristics of current literature focused on opioid use among PWD.

METHODS

Four databases were queried (i.e., Medline, PsycINFO, Embase, and CINAHL) for peer-reviewed, empirical, English-language, journal articles focused on long-term opioid use among PWD. Collected data points included: disability details (specific condition, onset of disability), opioid details (category of opioid use, and specified substance), study details, and design.

RESULTS

A total of 196 articles were included, with 83.7% published since 2000 largely from the US. The majority of articles (70.4%) focused on the use of opioids as medical treatment, with fewer articles focusing on recreational opioid use or substance use disorders. The majority of included sources (73%) focused on opioid use in acquired conditions; neuropathic pain (21.9%) and attention deficit hyperactivity disorder (20.4%) were the most commonly studied. Differences were observed in the distribution of disability conditions across category of opioid use and study design classification; 73.5% were considered observational in design.

CONCLUSIONS

The varied representation of disability conditions, and differences across opioid use category and study design classification point to a complicated relationship between opioid use and disability. The present research portfolio would benefit from research matching informational needs of a specific disability area or opioid use category to provide the evidence necessary to advance current knowledge and promote inclusion in national agendas.

Chronic Pain in Patients with Rheumatoid Arthritis

PURPOSE OF REVIEW

Chronic pain is highly prevalent in patients with rheumatoid arthritis (RA) and can cause various physical and psychological impairments. Unfortunately, the appropriate diagnosis of chronic pain syndromes in this population can be challenging because pain may be primary to RA-specific inflammation and/or secondary to other conditions, typically osteoarthritis (OA) and fibromyalgia (FM). This disparity further poses a clinical challenge, given that chronic pain can often be discordant or undetected with standard RA-specific surveillance strategies, including serological markers and imaging studies. In this review, we provide a robust exploration of chronic pain in the RA population with emphasis on epidemiology, mechanisms, and management strategies.

RECENT FINDINGS

Chronic pain associated with RA typically occurs in patients with anxiety, female sex, and elevated inflammatory status. Up to 50% of these patients are thought to have chronic pain despite appropriate inflammatory suppression, typically due to peripheral and central sensitization as well as secondary OA and FM. In addition to the standard-of-care management for OA and FM, patients with RA and chronic pain benefit from behavioral and psychological treatment options. Moreover, early and multimodal therapies, including non-pharmacological, pharmacological, interventional, and surgical strategies, exist, albeit with varying efficacy, to help suppress inflammation, provide necessary analgesia, and optimize functional outcomes. Overall, chronic pain in RA is a difficult entity for both patients and providers. Early diagnosis, improved understanding of its mechanisms, and initiation of early, targeted approaches to pain control may help to improve outcomes in this population.

Cost-Effectiveness of Repository Corticotropin Injection versus Standard of Care for the Treatment of Active Rheumatoid Arthritis

INTRODUCTION

Patients with active rheumatoid arthritis (RA) often have inadequately controlled symptoms and are unable to achieve remission or low disease activity despite aggressive treatment. This results in irreversible joint damage, adversely affecting patients' physical and social functioning. The objective was to estimate the cost-effectiveness of repository corticotropin injection (RCI) versus standard of care (SoC) in patients with active RA from the United States (US) payer and societal perspectives over two to three years.

METHODS

An individual-level microsimulation was developed to generate individual trajectories for patients with RA, using data from a published Phase 4 trial of RCI. These trajectories report a patient's disease pathway and associated cost and quality-of-life outcomes. The incremental cost-effectiveness ratio (ICER) of RCI versus SoC was assessed using the literature-derived direct medical and indirect costs, and quality-adjusted life-years (QALY) derived from a Phase 4 trial of RCI. The uncertainty in base case estimates of the parameters was evaluated in the sensitivity analysis.

RESULTS

Over two years, RCI has an incremental QALY gain of 1.591 and incremental cost of $183,965 and $117,443 from payer and societal perspective, respectively, resulting in an ICER of $115,629/QALY and $73,817/QALY compared to SoC. Over three years, RCI has an incremental QALY gain of 2.336 and incremental cost of $202,315 and $104,506 from payer and societal perspective, respectively, resulting in an ICER of $86,607/QALY and $44,737/QALY compared to SoC. Results from the probabilistic sensitivity analysis are consistent with those of the base case model.

CONCLUSION

RCI is a cost-effective strategy for patients with persistently active RA who are previously treated with disease-modifying anti-rheumatic drugs and corticosteroids compared to SoC over two to three years from the payer and societal perspectives at a US willingness-to-pay threshold of $150,000/QALY. Further, the economic benefit of RCI is realized with improvement in a patient's clinical and health outcomes.

Higher Medication Adherence and Lower Opioid Use Among Individuals with Autoimmune Disease Enrolled in an Adalimumab Patient Support Program in the United States

Introduction

Opioid use is prevalent among patients with autoimmune conditions, despite not being a recommended treatment. Tumor necrosis factor inhibitor (anti-TNF) therapy is an effective treatment for these autoimmune conditions, and patient support programs (PSPs) have been developed to help patients manage their prescribed treatments. This study was conducted to evaluate the impact of PSPs on anti-TNF adherence and opioid use using data on adalimumab (ADA), an anti-TNF.

Methods

The study used insurance claims data linked to ADA PSP data on patients who initiated ADA after 01/2015, were commercially insured, and had data coverage for 1 year before and after (i.e., during the follow-up period) ADA initiation. Patients with opioid use in the 3 months before ADA initiation were excluded. PSP patients enrolled in the PSP within 30 days of ADA initiation and had 2+ PSP nurse ambassador interactions; non-PSP patients had no PSP engagement. ADA adherence [proportion of days covered (PDC), persistence], opioid initiation, 2+ opioid fills, and opioid supply during follow-up were compared between cohorts using regression models that controlled for patient characteristics.

Results

Results were obtained for 1952 PSP and 728 non-PSP patients. PSP patients demonstrated better adherence to ADA than non-PSP patients, including higher PDC and persistence (all p < 0.001). PSP patients were 13% less likely to initiate opioids and 26% less likely to have at least 2 fills than non-PSP patients, and they had fewer days of opioid supply (all p < 0.01).

Conclusions

This study supports the benefit of PSPs and suggests that the ADA PSP is associated with improved adherence and potentially lower opioid use.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-021-00309-9.

Hemokinin-1 as a Mediator of Arthritis-Related Pain via Direct Activation of Primary Sensory Neurons

The tachykinin hemokinin-1 (HK-1) is involved in immune cell development and inflammation, but little is known about its function in pain. It acts through the NK1 tachykinin receptor, but several effects are mediated by a yet unidentified target. Therefore, we investigated the role and mechanism of action of HK-1 in arthritis models of distinct mechanisms with special emphasis on pain. Arthritis was induced by i.p. K/BxN serum (passive transfer of inflammatory cytokines, autoantibodies), intra-articular mast cell tryptase or Complete Freund's Adjuvant (CFA, active immunization) in wild type, HK-1- and NK1-deficient mice. Mechanical- and heat hyperalgesia determined by dynamic plantar esthesiometry and increasing temperature hot plate, respectively, swelling measured by plethysmometry or micrometry were significantly reduced in HK-1-deleted, but not NK1-deficient mice in all models. K/BxN serum-induced histopathological changes (day 14) were also decreased, but early myeloperoxidase activity detected by luminescent in vivo imaging increased in HK-1-deleted mice similarly to the CFA model. However, vasodilation and plasma protein extravasation determined by laser Speckle and fluorescent imaging, respectively, were not altered by HK-1 deficiency in any models. HK-1 induced Ca2+-influx in primary sensory neurons, which was also seen in NK1-deficient cells and after pertussis toxin-pretreatment, but not in extracellular Ca2+-free medium. These are the first results showing that HK-1 mediates arthritic pain and cellular, but not vascular inflammatory mechanisms, independently of NK1 activation. HK-1 activates primary sensory neurons presumably via Ca2+ channel-linked receptor. Identifying its target opens new directions to understand joint pain leading to novel therapeutic opportunities.

Factors associated with commencing and ceasing opioid therapy in patients with rheumatoid arthritis

OBJECTIVE

To determine factors associated with opioid use in rheumatoid arthritis (RA) patients.

METHODS

Adult RA patients (n = 3225, 73% female, mean age 57 years, median follow-up 54 months) were recruited into the Australian Rheumatology Association Database (ARAD) between 2001-2015. A logistic regression examining both within- and between-patient effect sizes for time-varying covariates, and transition-state analysis for covariates associated with opioid commencement or cessation were used to examine determinants of current opioid use.

RESULTS

The population-averaged prevalence of any opioid use was 33% (95%CI 32-34), 9% (95% CI 8, 10) for high potency opioid use, and 62% (95% 60, 64) of patients reported opioid ever-use after five years of follow-up. Opioid use was higher in females and decreased with older baseline age. Within-patients opioid use was associated with higher self-reported pain and HAQ scores (p < 0.001), and NSAID (OR 1.88; 1.67-2.10), oral glucocorticoid (2.23;1.93-2.58), csDMARD (2.08;1.78-2.44) and bDMARD (1.22;1.06-1.40) treatment. Younger baseline age, higher pain scores, HAQ scores and oral GC use were important determinants of change in opioid use, associated with both a higher probability of commencing opioid use, and a lower probability of cessation. Paradoxically, NSAID and DMARD treatments were associated with both a lower probability of commencing opioids, and a lower probability of cessation.

CONCLUSIONS

There was a high prevalence of opioid use among RA patients, which was associated with pain, function and GC treatment. NSAID, and DMARD treatments obviate the need for opioids in some, but not all, patients.