Association Between Prescription Opioid Therapy for Noncancer Pain and Hepatitis C Virus Seroconversion

IMPORTANCE

Initiation of injection drug use may be more frequent among people dispensed prescription opioid therapy for noncancer pain, potentially increasing the risk of hepatitis C virus (HCV) acquisition.

OBJECTIVE

To assess the association between medically dispensed long-term prescription opioid therapy for noncancer pain and HCV seroconversion among individuals who were initially injection drug use-naive.

DESIGN, SETTING, AND PARTICIPANTS

A population-based, retrospective cohort study of individuals tested for HCV in British Columbia, Canada, with linkage to outpatient pharmacy dispensations, was conducted. Individuals with an initial HCV-negative test result followed by 1 additional test between January 1, 2000, and December 31, 2017, and who had no history of substance use at baseline (first HCV-negative test), were included. Participants were followed up from baseline to the last HCV-negative test or estimated date of seroconversion (midpoint between HCV-positive and the preceding HCV-negative test).

EXPOSURES

Episodes of prescription opioid use for noncancer pain were defined as acute (<90 days) or long-term (≥90 days). Prescription opioid exposure status (long-term vs prescription opioid-naive/acute) was treated as time-varying in survival analyses. In secondary analyses, long-term exposure was stratified by intensity of use (chronic vs. episodic) and by average daily dose in morphine equivalents (MEQ).

MAIN OUTCOMES AND MEASURES

Multivariable Cox regression models were used to assess the association between time-varying prescription opioid status and HCV seroconversion.

RESULTS

A total of 382 478 individuals who had more than 1 HCV test were included, of whom more than half were female (224 373 [58.7%]), born before 1974 (201 944 [52.8%]), and younger than 35 years at baseline (196 298 [53.9%]). Participants were followed up for 2 057 668 person-years and 1947 HCV seroconversions occurred. Of the participants, 41 755 people (10.9%) were exposed to long-term prescription opioid therapy at baseline or during follow-up. The HCV seroconversion rate per 1000 person-years was 0.8 among the individuals who were prescription opioid-naive/acute (1489 of 1947 [76.5%] seroconversions; 0.4% seroconverted within 5 years) and 2.1 with long-term prescription opioid therapy (458 of 1947 [23.5%] seroconversions; 1.1% seroconverted within 5 years). In multivariable analysis, exposure to long-term prescription opioid therapy was associated with a 3.2-fold (95% CI, 2.9-3.6) higher risk of HCV seroconversion (vs prescription opioid-naive/acute). In separate Cox models, long-term chronic use was associated with a 4.7-fold higher risk of HCV seroconversion (vs naive/acute use 95% CI, 3.9-5.8), and long-term higher-dose use (≥90 MEQ) was associated with a 5.1-fold higher risk (vs naive/acute use 95% CI, 3.7-7.1).

CONCLUSIONS AND RELEVANCE

In this cohort study of people with more than 1 HCV test, long-term prescription opioid therapy for noncancer pain was associated with a higher risk of HCV seroconversion among individuals who were injection drug use-naive at baseline or at prescription opioid initiation. These results suggest injection drug use initiation risk is higher among people dispensed long-term therapy and may be useful for informing approaches to identify and prevent HCV infection. These findings should not be used to justify abrupt discontinuation of long-term therapy, which could increase risk of harms.

Prescription opioid treatment for non-cancer pain and initiation of injection drug use: large retrospective cohort study

OBJECTIVE

To assess the association between long term prescription opioid treatment medically dispensed for non-cancer pain and the initiation of injection drug use (IDU) among individuals without a history of substance use.

DESIGN

Retrospective cohort study.

SETTING

Large administrative data source (containing information for about 1.7 million individuals tested for hepatitis C virus or HIV in British Columbia, Canada) with linkage to administrative health databases, including dispensations from community pharmacies.

PARTICIPANTS

Individuals age 11-65 years and without a history of substance use (except alcohol) at baseline.

MAIN OUTCOME MEASURES

Episodes of prescription opioid use for non-cancer pain were identified based on drugs dispensed between 2000 and 2015. Episodes were classified by the increasing length and intensity of opioid use (acute (lasting <90 episode days), episodic (lasting ≥90 episode days; with <90 days' drug supply and/or <50% episode intensity), and chronic (lasting ≥90 episode days; with ≥90 days' drug supply and ≥50% episode intensity)). People with a chronic episode were matched 1:1:1:1 on socioeconomic variables to those with episodic or acute episodes and to those who were opioid naive. IDU initiation was identified by a validated administrative algorithm with high specificity. Cox models weighted by inverse probability of treatment weights assessed the association between opioid use category (chronic, episodic, acute, opioid naive) and IDU initiation.

RESULTS

59 804 participants (14 951 people from each opioid use category) were included in the matched cohort, and followed for a median of 5.8 years. 1149 participants initiated IDU. Cumulative probability of IDU initiation at five years was highest for participants with chronic opioid use (4.0%), followed by those with episodic use (1.3%) and acute use (0.7%), and those who were opioid naive (0.4%). In the inverse probability of treatment weighted Cox model, risk of IDU initiation was 8.4 times higher for those with chronic opioid use versus those who were opioid naive (95% confidence interval 6.4 to 10.9). In a sensitivity analysis limited to individuals with a history of chronic pain, cumulative risk for those with chronic use (3.4% within five years) was lower than the primary results, but the relative risk was not (hazard ratio 9.7 (95% confidence interval 6.5 to 14.5)). IDU initiation was more frequent at higher opioid doses and younger ages.

CONCLUSIONS

The rate of IDU initiation among individuals who received chronic prescription opioid treatment for non-cancer pain was infrequent overall (3-4% within five years) but about eight times higher than among opioid naive individuals. These findings could have implications for strategies to prevent IDU initiation, but should not be used as a reason to support involuntary tapering or discontinuation of long term prescription opioid treatment.

Evaluating the efficacy of intranasal oxytocin on pain and function among individuals who experience chronic pain: a protocol for a multisite, placebo-controlled, blinded, sequential, within-subjects crossover trial

INTRODUCTION

Current treatments for chronic pain (eg, opioids) can have adverse side effects and rarely result in resolution of pain. As such, there is a need for adjuvant analgesics that are non-addictive, have few adverse side effects and are effective for pain management across several chronic pain conditions. Oxytocin is a naturally occurring hormone that has gained attention for its potential analgesic properties. The objective of this trial is to evaluate the efficacy of intranasal oxytocin on pain and function among adults with chronic pain.

METHODS AND ANALYSIS

This is a placebo-controlled, triple-blind, sequential, within-subject crossover trial. Adults with chronic neuropathic, pelvic and musculoskeletal pain will be recruited from three Canadian provinces (British Columbia, Alberta and Newfoundland and Labrador, respectively). Enrolled patients will provide one saliva sample pretreatment to evaluate basal oxytocin levels and polymorphisms of the oxytocin receptor gene before being randomised to one of two trial arms. Patients will self-administer three different oxytocin nasal sprays twice daily for a period of 2 weeks (ie, 24 IU, 48 IU and placebo). Patients will complete daily diaries, including standardised measures on day 1, day 7 and day 14. Primary outcomes include pain and pain-related interference. Secondary outcomes include emotional function, sleep disturbance and global impression of change. Intention-to-treat analyses will be performed to evaluate whether improvement in pain and physical function will be observed posttreatment.

ETHICS AND DISSEMINATION

Trial protocols were approved by the Newfoundland and Labrador Health Research Ethics Board (HREB #20227), University of British Columbia Clinical Research Ethics Board (CREB #H20-00729), University of Calgary Conjoint Health Research Ethics Board (REB20 #0359) and Health Canada (Control # 252780). Results will be disseminated through publication in peer-reviewed journals and presentations at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04903002; Pre-results.

Cohort profile: development and characteristics of a retrospective cohort of individuals dispensed prescription opioids for non-cancer pain in British Columbia, Canada

PURPOSE

Prescription opioids (POs) are widely prescribed for chronic non-cancer pain but are associated with several risks and limited long-term benefit. Large, linked data sources are needed to monitor their harmful effects. We developed and characterised a retrospective cohort of people dispensed POs.

PARTICIPANTS

We used a large linked administrative database to create the Opioid Prescribing Evaluation and Research Activities cohort of individuals dispensed POs for non-cancer pain in British Columbia (BC), Canada (1996-2015). We created definitions to categorise episodes of PO use based on a review of the literature (acute, episodic, chronic), developed an algorithm for inferring clinical indication and assessed patterns of PO use across a range of characteristics.

FINDINGS TO DATE

The current cohort includes 1.1 million individuals and 3.4 million PO episodes (estimated to capture 40%-50% of PO use in BC). The majority of episodes were acute (81%), with most prescribed for dental or surgical pain. Chronic use made up 3% of episodes but 88% of morphine equivalents (MEQ). Across the acute to episodic to chronic episode gradient, there was an increasing prevalence of higher potency POs (hydromorphone, oxycodone, fentanyl, morphine), long-acting formulations and chronic pain related indications (eg, back, neck, joint pain). Average daily dose (MEQ) was similar for acute/episodic but higher for chronic episodes. Approximately 7% of the cohort had a chronic episode and chronic pain was the characteristic most strongly associated with chronic PO use. Individuals initiating a chronic episode were also more likely to have higher social/material deprivation and previous experience with a mental health condition or a problem related to alcohol or opioid use. Overall, these findings suggest our episode definitions have face validity and also provide insight into characteristics of people initiating chronic PO therapy.

FUTURE PLANS

The cohort will be refreshed every 2 years. Future analyses will explore the association between POs and adverse outcomes.

Does readiness to change influence pain-related outcomes after an educational intervention for people with chronic pain? A pragmatic, preliminary study

Background: There is a strong association between chronic pain and unhelpful pain cognitions. Educating patients on pain neuroscience has been shown to reduce pain catastrophization, kinesiophobia, and self-perceived disability. This study investigated whether a group-based pain neuroscience education (PNE) session influenced pain-related outcomes, and whether readiness to change moderated these outcomes.Method: In a pragmatic pre-post-intervention study using a convenience sample, adults with chronic pain participated in one, 90-120 minute PNE session. Pain-related outcomes (i.e. pain catastrophization, kinesiophobia, disability, and pain neuroscience knowledge) and the Pain Stage of Change Questionnaire (PSOCQ) were assessed at baseline and immediately post-intervention. Paired t-tests evaluated pre-post changes in outcomes, and linear regression examined the impact of PSOCQ score changes on PNE-induced changes in clinical outcomes.Results: Sixty-five participants were recruited. All outcomes showed positive intervention effects (p < .01). Relationships between changes in PSOCQ subscale scores and change in post-intervention pain-related outcomes were found; 'Pre-Contemplation' was positively associated with pain catastrophization (p = .01), and 'Action' was negatively associated with kinesiophobia (p = .03).Conclusion: Consistent with previous research, there were improvements in outcomes associated with chronic pain after PNE. Some of these improvements were predicted by changes in PSOCQ scores, however, these findings are preliminary and require further investigation using controlled research designs.

Are we missing post-thrombotic syndrome syndrome? An orthopaedic perspective in lower limb arthroplasty

2-5% of patients undergoing hip or knee arthroplasty develop a symptomatic DVT; there is evidence to suggest that without prophylaxis 40-60% of patients have a subclinical DVT. This can be reduced by around half with appropriate thromboprophylaxis; there still remains a significant incidence of subclinical DVT. Therefore, it is important to know, as orthopaedic surgeons, if our patients undergoing large joint arthroplasty are being adversely affected. Post-thrombotic syndrome (PTS) is usually associated with symptomatic DVT, and the purpose of this paper is to address if asymptomatic DVT is also associated with an increased risk of PTS. The majority of evidence gathered does not support a link; therefore, there is no evidence to warrant a change in practice to warn patients of a potential risk or to routinely screen asymptomatic patients.

Maraviroc can improve lipid profiles in dyslipidemic patients with HIV: results from the MERIT trial

PURPOSE

We investigated the effects of maraviroc, the first approved CC-chemokine receptor 5 (CCR5) antagonist, on blood lipids in a post hoc analysis of the phase 3 MERIT study in treatment-naïve patients.

METHODS

Patients received maraviroc 300 mg twice daily (n = 360) or efavirenz 600 mg once daily (n = 361), both in combination with zidovudine/lamivudine, for up to 96 weeks. Baseline and on- treatment lipid profiles were analyzed according to National Cholesterol Education Program (NCEP) thresholds.

RESULTS

Baseline characteristics and lipid profiles were comparable between groups. Among patients with total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c) below NCEP treatment thresholds at baseline, significantly more efavirenz- than maraviroc-treated patients exceeded those thresholds at 96 weeks (TC: 35% [74/209] vs 11% [20/188], P < .0001; LDL-c: 23% [47/197] vs 8% [15/183], P < .0001). Among patients exceeding NCEP thresholds at baseline, significantly more efavirenz- than maraviroc-treated patients exceeded the thresholds at 96 weeks (TC: 83% [24/29] vs 50% [17/34], P = .0084; LDL-c: 86% [19/22] vs 55% [16/29], P = .0314). Of those with baseline high- density lipoprotein cholesterol (HDL-c) < 40 mg/dL, 43% (56/130) of maravirocand 62% (86/139) of efavirenz-treated patients achieved HDL-c≥40 mg/dL at 96 weeks (P = .0020).

CONCLUSIONS

Maraviroc was not associated with elevations in TC, LDL-c, or triglycerides and showed beneficial effects on lipid profiles of dyslipidemic patients.

The food consumption patterns and perceptions of dietary advice of older people

BACKGROUND: Prevention policies do not have an upper age limit, and as the overwhelming majority of older people continue to reside in the community there is a growing role for community dietetics and primary care team members in the promotion of healthy eating. METHOD: The multi-method project ascertained the dietary beliefs and practices of older people residing in high-income, low-income and rural localities of Scotland. One hundred and fifty-two people aged 75 years and over were interviewed using a semistructured interview schedule and 24-h food recall questionnaire. RESULTS: An analysis of the food recall questionnaire demonstrated that the diets of the elderly appear to differ little from the Scottish population as a whole. In all groups there was an under consumption of fruits and vegetables reported. Findings from the interviews demonstrated that dietary beliefs were found to be firmly rooted in childhood and lifetime experiences. Participants defined healthy eating as 'proper meals', 'proper foods', and a variety of foods eaten in moderation. These definitions were based upon the consumption of fresh foods which would be considered healthy. Changing and conflicting advice on health and nutrition was contrasted with personal experiences. Few knew of the role of the dietitian or community dietitian. CONCLUSIONS: This study demonstrates a contrast between stated beliefs and actual consumption patterns. Access to food, and the cost and quality of foods impacted upon food practices. The role of the community dietitian should be promoted. Advice on healthy eating must work with contemporary practices and beliefs building upon positive aspects of diet and eating and involving the food industry, retail sector and health services.