Association between opioid-related deaths and prescribed opioid dose and psychotropic medicines in England: a case-crossover study

Fatal drug overdoses in individuals treated pharmacologically for chronic pain: a nationwide register-based study

INTRODUCTION

Chronic pain patients may be at an increased risk for drug overdoses as a result of comorbid psychiatric disorders and treatment with risk-increasing prescription medications, such as opioids. We aimed to characterise fatal drug overdoses and investigate factors associated with the deaths among individuals who had been treated pharmacologically for chronic pain.

METHODS

We included all individuals who received analgesics reimbursed for chronic pain in Norway during 2010-9 (n=569 047). Among this population, we identified all individuals with drug overdoses as cause of death (cases). Extracting data from national registries on diagnoses, filled prescriptions, and socioeconomic variables, we used a nested case-control design to compare the cases with age- and sex-matched controls from the study population.

RESULTS

Overall, 623 (0.11%) individuals in the study population died of an overdose. Most, 66.8%, had overdosed accidentally, and 61.9% as a result of pharmaceutically available opioids. Compared with the controls (n=62 245), overdoses overall were associated strongly with substance use disorders (adjusted odds ratio 7.78 [95% confidence interval 6.20-9.77]), use of combinations of opioids, benzodiazepines and related drugs and gabapentinoids (4.60 [3.62-5.85]), previous poisoning with pharmaceuticals (2.78 [2.20-3.51]), and with living alone the last year of life (2.11 [1.75-2.54]). Intentional overdoses had a stronger association with previous poisonings with pharmaceuticals whereas accidental overdoses were strongly associated with substance use disorders.

CONCLUSIONS

This study shows the need for better identification of overdose and suicide risk in individuals treated for chronic pain. Extra caution is needed when treating complex comorbid disorders, especially with overdose risk-increasing medications.

Preventable deaths involving opioids in England and Wales, 2013-2022: a systematic case series of coroners' reports

BACKGROUND

Opioid deaths have increased in England and Wales. Coroners' Prevention of Future Deaths reports (PFDs) provide important insights that may enable safer use and avert harms, yet reports implicating opioids have not been synthesized. We aimed to identify opioid-related PFDs and explore coroners' concerns to prevent future deaths.

METHODS

In this systematic case series, we screened 3897 coronial PFDs dated between 01 July 2013 and 23 February 2022, obtained by web scraping the UK's Courts and Tribunals Judiciary website. PFDs were included when an opioid was implicated in the death. Included PFDs were descriptively analysed, and content analysis was used to assess concerns reported by coroners.

RESULTS

Opioids were involved in 219 deaths reported in PFDs (5·6% of PFDs), equating to 4418 years of life lost (median 33 years/person). Morphine (29%), methadone (23%) and diamorphine (16%) were the most common implicated opioids. Coroners most frequently raised concerns regarding systems and protocols (52%) or safety issues (15%). These concerns were most often addressed to National Health Service (NHS) organizations (51%), but response rates were low overall (47%).

CONCLUSIONS

Opioids could be used more safely if coroners' concerns in PFDs were addressed by national organizations such as NHS bodies, government agencies and policymakers, as well as individual prescribing clinicians.

Evaluating the use of methods to mitigate bias from non-transient medications in the case-crossover design: A systematic review

PURPOSE

The case-crossover design is a self-controlled study design used to compare exposure immediately preceding an event occurrence with exposure in earlier control periods. The design is most suitable for transient exposures in order to avoid biases that can be problematic when using the case-crossover design for non-transient (i.e., chronic) exposures. Our goal was to conduct a systematic review of case-crossover studies and its variants (case-time-control and case-case-time-control) in order to compare design and analysis choices by medication type.

METHODS

We conducted a systematic search to identify recent case-crossover, case-time-control, and case-case-time-control studies focused on medication exposures. Articles indexed in MEDLINE and EMBASE using these study designs that were published between January 2015 and December 2021 in the English language were identified. Reviews, methodological studies, commentaries, articles without medications as the exposure of interest, and articles with no available full text were excluded. Study characteristics including study design, outcome, risk window, control window, reporting of discordant pairs, and inclusion of sensitivity analyses were summarized overall and by medication type. We further evaluated the implementation of recommended methods to account for biases introduced by non-transient exposures among articles that used the case-crossover design on a non-transient exposure.

RESULTS

Of the 2036 articles initially identified, 114 articles were included. The case-crossover was the most common study design (88%), followed by the case-time-control (17%), and case-case-time-control (3%). Fifty-three percent of the articles included only transient medications, 35% included only non-transient medications, and 12% included both. Across years, the proportion of case-crossover articles evaluating a non-transient medication ranged from 30% in 2018 to 69% in 2017. We found that 41% of the articles that evaluated a non-transient medication did not apply any of the recommended methods to account for biases and more than half of which were conducted by authors with no previous publication history of case-crossover studies.

CONCLUSION

Using the case-crossover design to evaluate a non-transient medication remains common in pharmacoepidemiology. Researchers should apply appropriate design and analysis choices when opting to use a case-crossover design with non-transient medication exposures.

Inhaled Δ9-tetrahydrocannabinol does not enhance oxycodone-induced respiratory depression: randomised controlled trial in healthy volunteers

BACKGROUND

In humans, the effect of cannabis on ventilatory control is poorly studied, and consequently, the effect of Δ⁹-tetrahydrocannabinol (THC) remains unknown, particularly when THC is combined with an opioid. We studied the effect of THC on breathing without and with oxycodone pretreatment. We hypothesised that THC causes respiratory depression, which is amplified when THC and oxycodone are combined.

METHODS

In this randomised controlled crossover trial, healthy volunteers were administered inhaled Bedrocan® 100 mg (Bedrocan International B.V., Veendam, The Netherlands), a pharmaceutical-grade high-THC cannabis variant (21.8% THC; 0.1% cannabidiol), after placebo or oral oxycodone 20 mg pretreatment; THC was inhaled 1.5 and 4.5 h after placebo or oxycodone intake. The primary endpoint was isohypercapnic ventilation at an end-tidal Pco₂ of 55 mm Hg or 7.3 kPa (V_E55), measured at 1-h intervals for 7 h after placebo/oxycodone intake.

RESULTS

In 18 volunteers (age 22 yr [3]; 9 [50%] female), oxycodone produced a 30% decrease in V_E55, whereas placebo was without effect on V_E55. The first cannabis inhalation resulted in V_E55 changing from 20.3 (3.1) to 23.8 (2.4) L min^-1 (P=0.06) after placebo, and from 11.8 (2.8) to 13.0 (3.9) L min^-1 (P=0.83) after oxycodone. The second cannabis inhalation also had no effect on V_E55, but slightly increased sedation.

CONCLUSIONS

In humans, THC has no effect on ventilatory control after placebo or oxycodone pretreatment.

CLINICAL TRIAL REGISTRATION

2021-000083-29 (EU Clinical Trials Register.).

Risk of parkinsonism and related movement disorders with gabapentinoids or tramadol: A case-crossover study

INTRODUCTION

A safety signal concerning parkinsonism and related movement disorders with gabapentinoids (gabapentin and pregabalin) or tramadol was detected by reviewing individual case reports and data mining in spontaneous report databases. Well-designed pharmacoepidemiological studies are needed to assess the signal.

OBJECTIVE

This study aimed to investigate the association of exposure to gabapentinoids or tramadol with the risk of parkinsonism and related movement disorders.

METHODS

We conducted a case-crossover study using a Japanese electronic medical records database. Patients with newly diagnosed parkinsonism or related movement disorders between January 1, 2007, and April 14, 2019, were identified. The diagnosis date of outcomes was defined as the index date. We assessed the exposure of each patient to gabapentinoids or tramadol during a 90-day hazard period ending 1 day before the index date and in three 90-day reference periods. Multivariable conditional logistic regression models were employed to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). To confirm the robustness of the primary findings, we also performed sensitivity analyses using a case-case-time-control design, a different time window for hazard and reference periods, a different definition of outcome, and different number of reference periods.

RESULTS

A total of 28,972 eligible cases were included in the primary analysis. Exposure to gabapentinoids (aOR, 2.12; 95% CI, 1.73-2.61) and tramadol (aOR, 2.04; 95% CI, 1.57-2.64) was associated with increased risk. Results were consistent across sensitivity analyses.

CONCLUSION

Our findings serve as a caution to physicians who prescribe gabapentinoids or tramadol in routine clinical practice.

Pharmacological data science perspective on fatal incidents of morphine treatment

Morphine prescribed for analgesia has caused drug-related deaths at an estimated incidence of 0.3% to 4%. Morphine has pharmacological properties that make it particularly difficult to assess the causality of morphine administration with a patient's death, such as its slow transfer between plasma and central nervous sites of action and the existence of the active metabolite morphine-6-glucuronide with opioid agonistic effects, Furthermore, there is no well-defined toxic dose or plasma/blood concentration for morphine. Dosing is often adjusted for adequate pain relief. Here, we summarize reported deaths associated with morphine therapy, including associated morphine exposure and modulating patient factors such as pharmacogenetics, concomitant medications, or comorbidities. In addition, we systematically analyzed published numerical information on the stability of concentrations of morphine and its relevant metabolites in biological samples collected postmortem. A medicolegal case is presented in which the causality of morphine administration with death was in dispute and pharmacokinetic modeling was applied to infer the administered dose. The results of this analytical review suggest that (i) inference from postmortem blood concentrations to the morphine dose administered has low validity and (ii) causality between a patient's death and the morphine dose administered remains a highly context-dependent and collaborative assessment among experts from different medical specialties.

Opioid epidemic: lessons learned and updated recommendations for misuse involving prescription versus non-prescription opioids

INTRODUCTION

In the past decades, the opioid crisis has heavily impacted parts of the US society and has been followed by an increase in the use of opioids worldwide. It is of paramount importance that we explore the origins of the US opioid epidemic to develop best practices to tackle the rising tide of opioid overdoses.

AREAS COVERED

In this expert review, we discuss opioid (over)prescription, change in perception of pain, and false advertisement of opioid safety as the leading causes of the US opioid epidemic. Then, we review the evidence about opioid dependence and addiction potential and provide current knowledge about predictors of aberrant opioid-related behavior. Lastly, we discuss different approaches that were considered or undertaken to combat the rising tide of opioid-related deaths by regulatory bodies, pharmaceutical companies, and health-care professionals. For this expert review, we considered published articles relevant to the topic under investigation that we retrieved from Medline or Google scholar electronic database.

EXPERT OPINION

The opioid epidemic is a dynamic process with many underlying mechanisms. Therefore, no single approach may be best suited to combat it. In our opinion, the best way forward is to employ multiple strategies to tackle different underlying mechanisms.

Increasing trend in accidental pharmaceutical opioid overdose deaths and diverging overdose death correlates following the opioid prescription policy liberalization in Norway 2010-2018

BACKGROUND

During the last decade, opioid prescription policies in Norway have been liberalised and pharmaceutical opioid (PO) dispensing has increased. Against this backdrop, we examined the trends in and the correlates of accidental overdose deaths attributable to PO in the period 2010-2018 in comparison with traditional heroin overdose deaths.

METHODS

Accidental overdose deaths attributable to PO or heroin were identified through the Norwegian Cause of Death Registry (n = 1267) and cross-linked with population and patient registries. Overdose death correlates were examined using multivariable logistic regression.

FINDINGS

The trend in accidental overdose deaths attributable to PO increased significantly from 2010 to 2018. Females, people aged 50 years or older, disability pension recipients and/or those with the highest net wealth had a greater risk of a PO vs. heroin overdose death, while those dying in public spaces, living in urban areas, having recent specialized drug treatment encounters, and/or criminal charge(s) had a lower risk. Among those with primary health care encounters, those with back problems and accidents and injuries had a greater risk of a PO vs. heroin overdose death, while those with a substance use disorder had a lower risk.

CONCLUSION

The increase in accidental overdose deaths attributable to PO coincides with the period of opioid prescription policy liberalization and an increase in PO consumption in Norway. The PO and heroin overdose deaths differed in terms of the associated sociodemographic characteristics, primary and secondary health care encounters, diagnoses, and criminal charges, indicating a need for additional interventions aimed at preventing PO overdose deaths specifically.

Association between prescription opioid use and unplanned intensive care unit admission and mortality in the adult population of the Netherlands: a registry study

BACKGROUND

Opioid overdoses are increasing in the Netherlands, and there may be other harms associated with prescription opioid use. We investigated the relationship between prescription opioid use and unplanned ICU admission and death.

METHODS

This is an analysis of linked government registries of the adult Dutch population (age ≥18 years) alive on January 1, 2018. The co-primary outcomes were ICU admission and death up to 1 year. Crude event rates and event-specific adjusted hazard rates (aHRs) with 95% confidence intervals (CIs) were calculated using multivariable analysis for people with and without exposure to an opioid prescription.

RESULTS

We included 13 813 173 individuals, of whom 32 831 were admitted to the ICU and 152 259 died during the 1 year follow-up. Rates of ICU admission and death amongst people who reimbursed an opioid prescription were 5.87 and 62.2 per 1000 person-years, and rates of ICU admission and death in those without a prescription were 2.03 and 6.34, respectively. Exposed individuals had a higher rate of both ICU admission (aHR 2.53; 95% CI: 2.45-2.60) and death (aHR 7.11; 95% CI: 7.02-7.19) compared with unexposed individuals. Both outcomes were more frequent amongst prescription opioid users across a range of subgroups.

CONCLUSIONS

The rate of ICU admission and death was higher amongst prescription opioid users than non-users in the full cohort and in subgroups. These findings represent an important public health concern.