Characterisation of concurrent use of prescription opioids and benzodiazepine/Z-drugs in Alberta, Canada: a population-based study

Long-term use of prescription opioids for non-cancer pain and mortality: a population-based, propensity-weighted cohort study

OBJECTIVE

The objective of this study was to identify factors associated with long-term opioid use and to assess the association between long-term use and death.

STUDY DESIGN

Retrospective cohort study combining several population-wide databases and covering a population of five million inhabitants, including all adults who were initiated on opioid treatment from 2014 to 2018 for non-cancer pain.

METHODS

We used logistic regression models to identify factors associated with chronic opioid use and carried out survival analyses using multivariable Cox regression modelling for all-cause mortality during follow-up using inverse probability of treatment weighting (IPTW) and propensity scores based on the probability of using opioids chronically.

RESULTS

Among 760,006 patients, 82,423 (10.85%) used opioids for 90 days or more after initiation. Initial therapy characteristics associated with higher risk for long-term use were initiating with long- and short-acting opioids (when compared to tramadol, odds ratio [OR]: 2.63, 95% confidence interval [CI]: 2.57, 2.69 and OR: 1.60, 95%CI: 1.46, 1.76, respectively), using higher daily doses (when compared to 50 morphine milligramme equivalent [MME] or less, prescribing 50 to 89 daily MME, OR: 1.76, 95%CI: 1.65, 1.87; 90 to 119 daily MME, OR: 2.44, 95%CI: 1.99, 3.01; and more than 120 daily MME, OR: 1.77, 95%CI: 1.64, 1.91), and overlapping with gabapentinoids (OR: 2.26, 95%CI: 2.20, 2.32), benzodiazepines (OR: 1.32, 95%CI: 1.30, 1.35), and antipsychotics (OR: 1.21, 95%CI: 1.16, 1.26). After IPTW, chronic opioid use was associated with higher risk of all-cause mortality when compared to short-term use (Hazard Ratio (HR): 1.37, 95%CI: 1.32, 1.42). Sensitivity analyses provided similar results.

CONCLUSION

These findings may help healthcare managers to identify and address patients at higher risk of long-term use and riskier prescription patterns.

Association Between Concurrent Use of Benzodiazepines and Opioids and Health Care Utilization Among Patients With Cancer in Puerto Rico

PURPOSE

To evaluate the association between concurrent use of opioids and benzodiazepines (BZDs) and emergency room (ER) visits and hospital admissions in patients with cancer.

METHODS

Data were obtained from the Puerto Rico Central Cancer Registry-Health Insurance Linkage. Odds ratios (ORs) with 95% CIs and incidence rate ratio (IRR) were estimated using logistic and negative binomial regression analyses to assess the association between concurrent use of opioids and BZDs (overlap of at least 7 days) and ER visits and hospital admissions.

RESULTS

A total of 9,259 patients were included in the main analysis. The logistic regression results showed a significant association between concurrent use of opioids and BZDs and at least one ER visit (OR, 1.28 [95% CI, 1.07 to 1.54]) or hospital admission (OR, 1.42 [95% CI, 1.18 to 1.71]) compared with individuals with BZDs alone, after adjusting for age, sex, comorbidity index, cancer stage, health insurance, and health region. Compared with individuals with opioid use alone, the association did not reach significance. In the negative binomial regression, a significant association was observed for ER visits (IRR, 1.52 [95% CI, 1.31 to 1.76]) and hospitalizations (IRR, 1.34 [95% CI, 1.20 to 1.50]) when compared with individuals with BZDs alone. Compared with individuals with opioids alone, it only reached significance for ER visits (IRR, 1.39 [95% CI, 1.20 to 1.61]).

CONCLUSION

Careful evaluation must be done before prescribing concurrent opioids and BZDs in patients with cancer, as the results suggest that coprescribing may increase the odds of ER visits and hospitalizations.

Co-prescribing of Central Nervous System-Active Medications for COPD Patients: Impact on Emergency Room Visits and Hospitalization

BACKGROUND

Anxiety and chronic pain are common comorbidities in patients with chronic obstructive pulmonary disease (COPD), which are frequently managed with benzodiazepines (BZDs) and opioids, respectively.

OBJECTIVE

The purpose of this study was to determine whether different combinations of opioids, BZD, and their substitutes-gabapentinoids (GABA) and selective serotonin reuptake inhibitors/serotonin-norepinephrine reuptake inhibitors (SSRIs/SNRIs)-are associated with lower risk of acute respiratory events in COPD patients with co-occurring chronic pain and anxiety.

METHODS

This retrospective cohort study used a nationally representative sample of Medicare beneficiaries with COPD, chronic pain, and anxiety. Patients were grouped based on drug combination (opioid + BZD/Z-hypnotics, opioid + GABA, opioid + SSRI/SNRI, BZD/Z-hypnotics + GABA, BZD/Z-hypnotics + SSRI/SNRI, GABA + SSRI/SNRI, or ≥3 drugs). The primary outcome was emergency room (ER) visit or hospitalization due to acute respiratory events assessed up to 180 days following initiation of drug combination. Overdose secondary to central nervous system (CNS)-related drugs was also assessed up to 180 days following initiation of drug combination.

RESULTS

The drug combination opioid + GABA was associated with decreased risk for ER visit (hazard ratio [HR] = 0.73; 95% CI = 0.61-0.87) and hospitalization (HR = 0.69; 95% CI = 0.55-0.85). Opioid + SSRI/SNRI also showed decreased risk for ER visit (HR = 0.84; 95% CI = 0.71-0.99). There was no significant difference in risk for CNS-related drug overdose among different drug combinations compared with opioid + BZD/Z-hypnotics.

CONCLUSION AND RELEVANCE

Opioids in combination with GABA and SSRI/SNRI demonstrate relatively lower risk for acute respiratory events among patients with COPD and comorbid chronic pain and anxiety. The findings emphasize the need for multimodal management in this vulnerable population.

A method for generating synthetic longitudinal health data

Getting access to administrative health data for research purposes is a difficult and time-consuming process due to increasingly demanding privacy regulations. An alternative method for sharing administrative health data would be to share synthetic datasets where the records do not correspond to real individuals, but the patterns and relationships seen in the data are reproduced. This paper assesses the feasibility of generating synthetic administrative health data using a recurrent deep learning model. Our data comes from 120,000 individuals from Alberta Health's administrative health database. We assess how similar our synthetic data is to the real data using utility assessments that assess the structure and general patterns in the data as well as by recreating a specific analysis in the real data commonly applied to this type of administrative health data. We also assess the privacy risks associated with the use of this synthetic dataset. Generic utility assessments that used Hellinger distance to quantify the difference in distributions between real and synthetic datasets for event types (0.027), attributes (mean 0.0417), Markov transition matrices (order 1 mean absolute difference: 0.0896, sd: 0.159; order 2: mean Hellinger distance 0.2195, sd: 0.2724), the Hellinger distance between the joint distributions was 0.352, and the similarity of random cohorts generated from real and synthetic data had a mean Hellinger distance of 0.3 and mean Euclidean distance of 0.064, indicating small differences between the distributions in the real data and the synthetic data. By applying a realistic analysis to both real and synthetic datasets, Cox regression hazard ratios achieved a mean confidence interval overlap of 68% for adjusted hazard ratios among 5 key outcomes of interest, indicating synthetic data produces similar analytic results to real data. The privacy assessment concluded that the attribution disclosure risk associated with this synthetic dataset was substantially less than the typical 0.09 acceptable risk threshold. Based on these metrics our results show that our synthetic data is suitably similar to the real data and could be shared for research purposes thereby alleviating concerns associated with the sharing of real data in some circumstances.

Trends and correlates of concurrent opioid and benzodiazepine and/or gabapentinoid use among Ontario nursing home residents

BACKGROUND

A concern with long-term opioid use is the increased risk arising when opioids are used concurrently with drugs that can potentiate their associated adverse effects. The drugs most often encountered are benzodiazepines (BZDs) and gabapentinoids. Our study objectives were to examine trends in the concurrent use of opioids and BZDs, or gabapentinoids, in a Canadian nursing home population over an 11-year period, and current resident-level correlates of this concurrent use.

METHODS

We conducted a population-based, repeated cross-sectional study among Ontario nursing home residents (>65 years) dispensed opioids between April 2009 and February 2020. For the last study year, we examined cross-sectional associations between resident characteristics and concurrent use of opioids with BZDs or gabapentinoids. Linked data on nursing home residents from clinical and health administrative databases was used. The yearly proportions of residents who were dispensed an opioid concurrently with a BZD or gabapentinoid were plotted with percent change derived from log-binomial regression models. Separate modified Poisson regression models estimated resident-level correlates of concurrent use of opioids with BZDs or gabapentinoids.

RESULTS

Over the study period, among residents dispensed an opioid there was a 53.2% relative decrease (30.7% to 14.4%) in concurrent BZD and a 505.4% relative increase (4.4% to 26.6%) in concurrent gabapentinoid use. In adjusted models, increasing age and worsening cognition were inversely associated with the concurrent use of both classes, but most other significantly related covariates were unique to each drug class (e.g., sex and anxiety disorders for BZD, pain severity and presence of pain-related conditions for gabapentinoids).

CONCLUSIONS

Co-administration of BZDs or gabapentinoids in Ontario nursing home residents dispensed opioids remains common, but the pattern of co-use has changed over time. Observed covariates of concurrent use in 2019/20 suggest distinct but overlapping resident populations requiring consideration of the relative risks versus benefits of this co-use and monitoring for potential harm.

Occurrence of involuntary movements after prolonged misuse of zolpidem: a case report

Zolpidem is a non-benzodiazepine agent used for short-term treatment of insomnia. Several cases of dependence and withdrawal from zolpidem are reported in the literature. Furthermore, involuntary movements after prolonged zolpidem misuse have been described. In this case report, a 69-year-old Italian woman with no history of diagnosed psychiatric or neurologic diseases developed uncontrolled movements and a depressive-anxious syndrome after twelve-year zolpidem misuse. The underlying mechanisms of involuntary movements occurring after long-term zolpidem intake are unknown; yet, we suggest that zolpidem might induce an increase in dopamine release through inhibition of gamma-aminobutyric acid neurons tonically suppressing dopamine cells. Future studies on the occurrence of persistent disorders after long-term benzodiazepine or Z-drug abuse are needed and clinicians should pay attention to the risk of tardive syndromes related to zolpidem misuse, especially in the case of long-term intake of over-therapeutic dosages.

Use of Benzodiazepines and Z-Drugs in Inflammatory Bowel Disease

INTRODUCTION

We estimated the incidence and prevalence of benzodiazepine and Z-drug (separately and jointly as BZD) use in the inflammatory bowel disease (IBD) population compared with matched controls without IBD and examined the association of mood/anxiety disorders (M/ADs) with the use of BZD from 1997 to 2017.

METHODS

Using administrative data from Manitoba, Canada, we identified 5,741 persons with incident IBD who were matched in a 1:5 ratio to controls on sex, birth year, and region. Validated case definitions were used to identify M/AD. Dispensations of BZD were identified. Multivariable generalized linear models were used to assess the association between IBD, M/AD, and BZD use.

RESULTS

In 2016, the incident age/sex-standardized benzodiazepine use rates per 1,000 were 28.06 (95% confidence interval [CI] 26.41-29.81) in the IBD cohort and 16.83 (95% CI 16.28-17.39) in controls (adjusted rate ratio = 1.69 [95% CI 1.56-1.79]). Benzodiazepine incidence rates were higher for women with IBD than men, but the RR between cases and controls were similar for men and women. The incident age/sex-standardized Z-drug use rate per 1,000 was 21.07 (95% CI 19.69-22.41) in the IBD cohort. This was 1.87-fold higher than in controls (95% CI 1.73-2.01). In 2017, approximately 20% of persons with IBD used benzodiazepines and 20% used Z-drugs. There was a subadditive effect of both benzodiazepine and Z-drug uses between IBD and M/AD after adjusting for covariates.

DISCUSSION

The use of BZD is more common in people with IBD than in population controls. Strategies to reduce the use of BZDs in persons with IBD and to offer alternative management strategies for M/ADs, sleep disorders, and other symptomatic concerns are needed.

Concurrent Use of Prescription Opioids and Gabapentinoids in Older Adults

INTRODUCTION

Concurrent use of prescription opioids with gabapentinoids may pose risks of serious drug interactions. Yet, little is known about the trends in and patient characteristics associated with concurrent opioid-gabapentinoid use among older Medicare opioid users with chronic noncancer pain.

METHODS

A cross-sectional study was conducted among Medicare older beneficiaries (aged ≥65 years) with chronic noncancer pain who filled ≥1 opioid prescription within 3 months after a randomly selected chronic noncancer pain diagnosis (index date) in a calendar year between 2011 and 2018. Patient characteristics were measured in the 6-month baseline before the index date, and concurrent opioid-gabapentinoid use for ≥1 day was measured in the 3-month follow-up after the index date. Multivariable modified Poisson regression hwas used to assess the trends and characteristics of concurrent opioid-gabapentinoid use. Analyses were conducted from January to June 2021.

RESULTS

Among 464,721 eligible older beneficiaries with chronic noncancer pain and prescription opioids, the prevalence of concurrent opioid-gabapentinoid use increased from 17.0% in 2011 to 23.5% in 2018 (adjusted prevalence ratio=1.48, 95% CI=1.45, 1.53). Concurrent users versus opioid-only users tended to be non-Black, low-income subsidy recipients, and Southern residents. The clinical factors associated with concurrent opioid-gabapentinoid use included having a diagnosis of neuropathic pain, polypharmacy, and risk factors for opioid-related adverse events.

CONCLUSIONS

Concurrent opioid-gabapentinoid use among older Medicare beneficiaries with chronic noncancer pain and prescription opioids has increased significantly between 2011 and 2018. Future studies are warranted to investigate the impact of concurrent use on outcomes in older patients. Interventions that reduce inappropriate concurrent use may target older patients with identified characteristics.

Inappropriate use of clinical practices in Canada: a systematic review

Background:

Inappropriate health care leads to negative patient experiences, poor health outcomes and inefficient use of resources. We aimed to conduct a systematic review of inappropriately used clinical practices in Canada.

Methods:

We searched multiple bibliometric databases and grey literature to identify inappropriately used clinical practices in Canada between 2007 and 2021. Two team members independently screened citations, extracted data and assessed methodological quality. Findings were synthesized in 2 categories: diagnostics and therapeutics. We reported ranges of proportions of inappropriate use for all practices. Medians and interquartile ranges (IQRs), based on the percentage of patients not receiving recommended practices (underuse) or receiving practices not recommended (overuse), were calculated. All statistics are at the study summary level.

Results:

We included 174 studies, representing 228 clinical practices and 28 900 762 patients. The median proportion of inappropriate care, as assessed in the studies, was 30.0% (IQR 12.0%–56.6%). Underuse (median 43.9%, IQR 23.8%–66.3%) was more frequent than overuse (median 13.6%, IQR 3.2%–30.7%). The most frequently investigated diagnostics were glycated hemoglobin (underused, range 18.0%–85.7%, n = 9) and thyroid-stimulating hormone (overused, range 3.0%–35.1%, n = 5). The most frequently investigated therapeutics were statin medications (underused, range 18.5%–71.0%, n = 6) and potentially inappropriate medications (overused, range 13.5%–97.3%, n = 9).

Interpretation:

We have provided a summary of inappropriately used clinical practices in Canadian health care systems. Our findings can be used to support health care professionals and quality agencies to improve patient care and safety in Canada.

Risk Prescriptions of Strong Opioids in the Treatment of Chronic Non-Cancer Pain by Primary Care Physicians in Catalonia: Opicat Padris Project

The prescription of strong opioids (SO) for chronic non-cancer pain (CNCP) is steadily increasing. This entails a high risk of adverse effects, a risk that increases with the concomitant prescription of SO with central nervous system depressant drugs and with the use of SO for non-recommended indications. In order to examine this concomitant risk prescription, we designed a descriptive, longitudinal, retrospective population-based study. Patients aged ≥15 years with a continued SO prescription for ≥3 months during 2013–2017 for CNCP were included. Of these, patients who had received concomitant prescriptions of SO and risk drugs (gabapentinoids, benzodiazepines and antidepressants) and those who had received immediate-release fentanyl (IRF) were selected. The study included 22,691 patients; 20,354 (89.7%) patients received concomitant risk prescriptions. Men and subjects with a higher socioeconomic status received fewer concomitant risk prescriptions. Benzodiazepines or Z-drugs were prescribed concomitantly with SO in 15,883 (70%) patients, antidepressants in 14,932 (65%) and gabapentinoids in 11,267 (49%), while 483 (21.32%) patients received IRF (2266 prescriptions in total) without a baseline SO. In conclusion, our study shows that a high percentage of patients prescribed SO for CNCP received concomitant prescriptions with known risks, as well as IRF for unauthorized indications.

Trends in prescribing pattern of opioid and benzodiazepine substitutes among Medicare part D beneficiaries from 2013 to 2018: a retrospective study

OBJECTIVE

Opioid and benzodiazepine co-prescribing is associated with a substantial increase in opioid overdose deaths. In this study, we examine the prescribing trends of substitutes of opioids and benzodiazepines alone or in combination, compared with opioids and benzodiazepines.

DESIGN

Retrospective cohort study.

SETTING

Data were collected using a 20% national sample of Medicare beneficiaries from 2013 to 2018.

PARTICIPANTS

4.1-4.3 million enrollees each year from 2013 to 2018.

INTERVENTION

None.

PRIMARY OUTCOME

We employ a generalised linear mixed models to calculate ORs for opioid use, benzodiazepine or Z-drug (benzos/Z-drugs) use, opioid/benzos/Z-drugs 30-day use, gabapentinoid use and (selective serotonin reuptake inhibitors (SSRI) and serotonin norepinephrine reuptake inhibitors (SNRIs)) use, adjusted for the repeated measure of patient. We then created two models to calculate the ORs for each year and comparing to 2013.

RESULTS

Opioid and benzos/Z-drugs use decreased by 2018 (aOR 0.626; 95% CI 0.622 to 0.630) comparing to 2013. We demonstrate a 36.3% and 9.9% increase rate of gabapentinoid and SSRI/SNRI use, respectively. Furthermore, combined gabapentinoid and SSRI/SNRI use increased in 2018 (aOR 1.422; 95% CI 1.412 to 1.431).

CONCLUSION

Little is known about the prescribing pattern and trend of opioid and benzodiazepine alternatives as analgesics. There is a modest shift from prescribing opioid and benzos/Z-drugs (alone or in combination) towards prescribing non-opioid analgesics-gabapentinoids with and without non-benzos/Z-drugs that are indicated for anxiety. It is unclear if this trend towards opioid/benzos/Z-drugs alternatives is associated with fewer drug overdose death, better control of pain and comorbid anxiety, and improved quality of life.

Relevance of Sleep Disturbances to Orthopaedic Surgery: A Current Concepts Narrative and Practical Review

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Sleep disturbances can increase the risk of falls and motor vehicle accidents and may reduce bone density.

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Poor sleep can lead to worse outcomes after fracture, such as chronic pain and delayed recovery.

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Orthopaedic surgeons can play an important role in the screening of sleep disorders among their patients.

Acute Care Use by Breast Cancer Patients on Adjuvant Chemotherapy in Alberta: Demonstrating the Importance of Measurement to Improving Quality

Breast cancer patients receiving adjuvant chemotherapy are at increased risk of acute care use. The incidence of emergency department (ED) visits and hospitalizations (H) have been characterized in other provinces but never in Alberta. We conducted a retrospective population-based cohort study using administrative data of women with stage I-III breast cancer receiving adjuvant chemotherapy. Rates of ED and H use in the 180 days following chemotherapy initiation were determined, and logistic regression was performed to identify risk factors. We found that 47% of women receiving adjuvant chemotherapy experienced ED or H, which compared favourably to other provinces. However, Alberta had the highest rate of febrile neutropenia-related ED visits, and among the highest chemotherapy-related ED visits. The incidence of acute care use increased over time, and there were significant institutional differences despite operating under a single provincial healthcare system. Our study demonstrates the need for systematic measurement and the importance of quality improvement programs to address this gap.

Endogenous opiates and behavior: 2019

This paper is the forty-second consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2019 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

'Z-trip'? A Comprehensive Overview and a Case-series of Zolpidem Misuse

Although believed safer compared to short-acting benzodiazepines (BZD), in the past few years a growing concern has developed relating to the abuse of Z-drugs, and specifically of zolpidem. Here we aim to review the evidence for the misuse of zolpidem and describe several related cases collected in Italy. A comprehensive overview is here carried by using several databases, and by combining the search strategy of free text terms and exploding a range of MESH headings relating to the topics of Zolpidem and Abuse and/or Misuse as follows: ((Zolpidem[Title/Abstract]) AND (Abuse[Title/Abstract]) OR (Misuse[Title/Abstract])), without time and/or language restrictions. Furthermore, a case series of 8 cases of zolpidem misuse and/or abuse, collected in different Italian psychiatric settings (psychiatric public hospital, psychiatric private rehabilitation clinic, and private practice), have been here described. According to our findings, zolpidem should be prescribed with the same caution as BZDs, especially in patients with a history of drug abuse or in the elderly. Behavioural modifications, including bizarre behaviours, psychomotor agitation, sleep-related complex behaviours have been reported. Monitoring of zolpidem use in selected populations is warranted. Psychiatrists and physicians should be aware of the misuse potential of zolpidem and adopt measures restricting its use.

Opioid use in medical cannabis authorization adult patients from 2013 to 2018: Alberta, Canada

BACKGROUND

The opioid overdose epidemic in Canada and the United States has become a public health crisis - with exponential increases in opioid-related morbidity and mortality. Recently, there has been an increasing body of evidence focusing on the opioid-sparing effects of medical cannabis use (reduction of opioid use and reliance), and medical cannabis as a potential alternative treatment for chronic pain. The objective of this study is to assess the effect of medical cannabis authorization on opioid use (oral morphine equivalent; OME) between 2013 and 2018 in Alberta, Canada.

METHODS

All adult patients defined as chronic opioid users who were authorized medical cannabis by their health care provider in Alberta, Canada from 2013 to 2018 were propensity score matched to non-authorized chronic opioid using controls. A total of 5373 medical cannabis patients were matched to controls, who were all chronic opioid users. The change in the weekly average OME of opioid drugs for medical cannabis patients relative to controls was measured. Interrupted time series (ITS) analyses was used to assess the trend change in OME during the 26 weeks (6 months) before and 52 weeks (1 year) after the authorization of medical cannabis among adult chronic opioid users.

RESULTS

Average age was 52 years and 54% were female. Patients on low dose opioids (< 50 OME) had an increase in their weekly OME per week (absolute increase of 112.1 OME, 95% CI: 104.1 to 120.3); whereas higher dose users (OME > 100), showed a significant decrease over 6 months (- 435.5, 95% CI: - 596.8 to - 274.2) compared to controls.

CONCLUSIONS

This short-term study found that medical cannabis authorization showed intermediate effects on opioid use, which was dependent on initial opioid use. Greater observations of changes in OME appear to be in those patients who were on a high dosage of opioids (OME > 100); however, continued surveillance of patients utilizing both opioids and medical cannabis is warranted by clinicians to understand the long-term potential benefits and any harms of ongoing use.

Concurrent prescriptions for opioids and benzodiazepines and risk of opioid overdose: protocol for a retrospective cohort study using linked administrative data

INTRODUCTION

Opioid overdoses have increased substantially over the last 20 years, with over 400 000 deaths in North America. While opioid prescribing has been a target of research, benzodiazepine and opioid co-intoxication has emerged as a potential risk factor. Our aim was to assess the risk of opioid overdose associated with concurrent use of opioids and benzodiazepines relative to opioids alone.

METHODS AND ANALYSIS

A retrospective cohort study will be conducted using medical claims data from adult residents of Montréal, Canada. We will create a cohort of new users of opioids (ie, no opioid dispensations in prior year) in 2000-2014 from people with at least 2 years of continuous health insurance. Those with any diagnosis or hospitalisation for cancer or palliative care in the 2 years before their first opioid dispensation will be excluded. On each person-day of follow-up, exposure status will be classified into one of four mutually exclusive categories: (1) opioid-only, (2) benzodiazepine-only, (3) both opioid and benzodiazepine (concurrent use) or (4) neither. Opioid overdose will be measured using diagnostic codes documented in the hospital discharge abstract database, physician billing claims from emergency department visits and death records. Using a marginal structural Cox proportional hazards model, we will compare the hazard of overdose during intervals of concurrent opioid and benzodiazepine use to intervals of opioid use alone, adjusted for sociodemographics, medical and psychiatric comorbidities, and substance use disorders.

ETHICS AND DISSEMINATION

This study is approved by the McGill Faculty of Medicine Institutional Review Board and the Commission d'access à l'information (Québec privacy commission). Results will be relevant to clinicians, policymakers and other researchers interested in co-prescribing practices of opioids and benzodiazepines. Study findings will be disseminated at relevant conferences and published in biomedical and epidemiological peer-reviewed journals.

Concurrent use of opioids and benzodiazepines/Z-drugs in Alberta, Canada and the risk of hospitalisation and death: a case cross-over study

OBJECTIVES

Coprescribing of benzodiazepines/Z-drugs (BZDs) and opioids is a drug-use pattern of considerable concern due to risk of adverse events. The objective of this study is to estimate the effect of concurrent use of BZDs on the risk of hospitalisations/emergency department (ED) visits and deaths among opioid users.

DESIGN, SETTING AND PARTICIPANTS

We conducted a population-based case cross-over study during 2016-2018 involving Albertans 18 years of age and over who received opioids. From this group, we identified 1 056 773 people who were hospitalised or visited the ED, and 31 998 who died.

INTERVENTION

Concurrent use of opioids and BZDs.

OUTCOMES

We estimated the risk of incident all-cause hospitalisation/ED visits and all-cause mortality associated with concurrent BZD use by applying a matched-pair analyses comparing concurrent use to opioid only use.

RESULTS

Concurrent BZD use occurred in 17% of opioid users (179 805/1 056 773). Overall, concurrent use was associated with higher risk of hospitalisation/ED visit (OR 1.13, p<0.001) and all cause death (OR 1.90; p<0.001). The estimated risk of hospitalisation/ED visit was highest in those >65 (OR 1.5; p<0.001), using multiple health providers (OR 1.67; p<0.001) and >365 days of opioid use (OR 1.76; p<0.001). Events due to opioid toxicity were also associated with concurrent use (OR 1.8; p<0.001). Opioid dose-response effects among concurrent patients who died were also noted (OR 3.13; p<0.001).

INTERPRETATION

Concurrent use of opioids and BZDs further contributes to the risk of hospitalisation/ED visits and mortality in Alberta, Canada over opioid use alone, with higher opioid doses, older age and increased number of unique health providers carrying higher risks. Regulatory bodies and health providers should reinforce safe drug-use practices and be vigilant about coprescribing.