All-Cause and Overdose Mortality Risk Among People Prescribed Opioids: A Systematic Review and Meta-analysis

A Dynamic Model of Opioid Overdose Deaths in Canada during the Co-Occurring Opioid Overdose Crisis and COVID-19 Pandemic

With over 40,000 opioid-related overdose deaths between January 2016 and June 2023, the opioid-overdose crisis is a significant public health concern for Canada. The opioid crisis arose from a complex system involving prescription opioid use, the use of prescription opioids not as prescribed, and non-medical opioid use. The increasing presence of fentanyl and its analogues in the illegal drugs supply has been an important driver of the crisis. In response to the overdose crisis, governments at the municipal, provincial/territorial, and federal levels have increased actions to address opioid-related harms. At the onset of the COVID-19 pandemic, concerns emerged over how the pandemic context may impact the opioid overdose crisis. Using evidence from a number of sources, we developed a dynamic mathematical model of opioid overdose death to simulate possible trajectories of overdose deaths during the COVID-19 pandemic. This model incorporates information on prescription opioid use, opioid use not as prescribed, non-medical opioid use, the level of fentanyl in the drug supply, and a measure of the proportion deaths preventable by new interventions. The simulated scenarios provided decision makers with insight into possible trajectories of the opioid crisis in Canada during the COVID-19 pandemic, highlighting the potential of the crisis to take a turn for the worse under certain assumptions, and thus, informing planning during a period when surveillance data were not yet available. This model provides a starting point for future models, and through its development, we have identified important data and evidence gaps that need to be filled in order to inform future action.

Mortality associated with bacterial and fungal infections and overdose among people with drug use diagnoses

PURPOSE

Hospital visits for drug use-related bacterial and fungal infections have increased alongside overdose deaths. The incidence of mortality from these infections and the comparison to overdose mortality is not established.

METHODS

This cohort study examined mortality outcomes among adults with drug use diagnoses who were insured by public and private plans during 2007 through 2018 in North Carolina. We examined bacterial- and fungal infection-related mortality and overdose mortality using cumulative incidence functions.

RESULTS

Among 131,522 people with drug use diagnoses, the median age was 45 years (interquartile range: 31-57), 58% were women and 65% had an opioid use disorder diagnosis. The 1-year incidence of bacterial and fungal infection-associated mortality was progressively higher as age increased (35-49 years: 9 per 10,000 people, 50-64 years: 23 per 10,000, 65+ years: 50 per 10,000 people). Conversely, the 1-year incidence of overdose mortality was markedly lower among older adults compared to those under the age of 65 (18-34 years: 34 deaths per 10,000 people; 35-49 years: 47 per 10,000; 50-64 years: 41 per 10,000; 65+ years: 9 per 10,000).

CONCLUSIONS

Bacterial and fungal infections and overdose were notable causes of death among adults with drug use diagnoses, and varied by age group.

Correlation Between Opioid Drug Prescription and Opioid-Related Mortality in Spain as a Surveillance Tool: Ecological Study

BACKGROUND

Opioid drug prescription (ODP) and opioid-related mortality (ORM) have increased in Spain. However, their relationship is complex, as ORM is registered without considering the type of opioid (legal or illegal).

OBJECTIVE

This ecological study aimed to examine the correlation between ODP and ORM in Spain and discuss their usefulness as a surveillance tool.

METHODS

This was an ecological descriptive study using retrospective annual data (2000-2019) from the Spanish general population. Data were collected from people of all ages. Information on ODP was obtained from the Spanish Medicines Agency in daily doses per 1000 inhabitants per day (DHD) for total ODP, total ODP excluding those with better safety protocols (codeine and tramadol), and each opioid drug separately. Rates of ORM (per 1,000,000 inhabitants) were calculated based on deaths registered (International Classification of Diseases, 10th Revision codes) as opioid poisoning by the National Statistics Institute, derived from the drug data recorded by medical examiners in death certificates. Opioid-related deaths were considered to be those that indicated opioid consumption (accidental, infringed, or self-inflicted) as the main cause of death: death due to accidental poisoning (X40-X44), intentional self-inflicted poisoning (X60-X64), drug-induced aggression (X85), and poisoning of undetermined intention (Y10-Y14). A descriptive analysis was carried out, and correlations between the annual rates of ORM and DHD of the prescribed opioid drugs globally, excluding medications of the least potential risk of overdose and lowest treatment tier, were analyzed using Pearson linear correlation coefficient. Their temporal evolution was analyzed using cross-correlations with 24 lags and the cross-correlation function. The analyses were carried out using Stata and StatGraphics Centurion 19.

RESULTS

The rate of ORM (2000-2019) ranged between 14 and 23 deaths per 1,000,000 inhabitants, with a minimum in 2006 and an increasing trend starting in 2010. The ODP ranged between 1.51 to 19.94 DHD. The rates of ORM were directly correlated with the DHD of total ODP (r=0.597; P=.006), total ODP without codeine and tramadol (r=0.934; P<.001), and every prescribed opioid except buprenorphine (P=.47). In the time analysis, correlations between DHD and ORM were observed in the same year, although not statistically significant (all P≥.05).

CONCLUSIONS

There is a correlation between greater availability of prescribed opioid drugs and an increase in opioid-related deaths. The correlation between ODP and ORM may be a useful tool in monitoring legal opiates and possible disturbances in the illegal market. The role of tramadol (an easily prescribed opioid) is important in this correlation, as is that of fentanyl (the strongest opioid). Measures stronger than recommendations need to be taken to reduce off-label prescribing. This study shows that not only is opioid use directly related to the prescribing of opioid drugs above what is desirable but also an increase in deaths.

Association between prescribed opioid dose and risk of motor vehicle crashes

ABSTRACT

Opioid-involved motor vehicle traffic fatalities have increased over the past 2 decades. However, the extent to which prescribed opioids increase the risk of motor vehicle crashes remains uncertain. This study used real-world healthcare claims data to examine the association between prescription opioid dose and motor vehicle crash risk. Using nationwide US commercial insurance claims data for 2010 to 2018, we identified 772,404 adults who received incident, noncancer opioid therapy. We examined associations between daily prescription opioid dose, calculated in morphine milligram equivalents (MME) from filled prescription claims, and risk of motor vehicle crashes, assessed as diagnoses of motor vehicle injuries in claims for emergency visits, inpatient hospitalizations, and ambulance transportation. We estimated associations using a within-individual design, which ruled out all time-stable confounding. We complemented the design with time-varying statistical adjustment for other pharmacotherapies and a negative control pain pharmacotherapy analysis (with incident cyclic antidepressant prescriptions). During 2,150,009 person-years of follow-up, there were 12,123 motor vehicle crashes (5.64 crashes per 1000 person-years). In within-individual comparisons, crash risk was greater during opioid prescription periods involving doses ≤60 MME/day (odds ratio [OR], 3.86; 95% confidence interval [CI], 3.54, 4.21), >60 to 120 MME/day (OR, 5.46; 95% CI, 4.44, 6.73), and >120 MME/day (OR, 3.45; 95% CI, 2.31, 5.15) than during off-treatment periods. The negative control analysis supported the specificity of the results to opioids rather than to other processes associated with pharmacologic pain management. These findings suggest that the receipt of prescription opioids, even at doses ≤60 MME/day, is associated with an increased risk of motor vehicle crashes.

County-level predictors of US drug overdose mortality: A systematic review

BACKGROUND

This systematic review summarized published literature on county-level predictors of drug overdose mortality in the United States (US).

METHODS

Peer-reviewed studies and doctoral dissertations published in English between 1990 and July 19, 2022 were identified from PubMed, Web of Science, ProQuest Dissertations & Theses, PsycINFO, CINAHL, and EconLit. Eligible studies examined at least one county-level predictor of drug overdose mortality in US counties. Two reviewers independently completed screening, quality assessment (with an adapted National Institutes of Health Quality Assessment Tool), and data extraction. Results were qualitatively summarized and grouped by predictor categories.

RESULTS

Of 56 studies included, 42.9% were subnational, and 53.6% were limited to opioid overdose. In multiple studies, measures related to opioid prescribing, illness/disability, economic distress, mining employment, incarceration, family distress, and single-parent families were positively associated with drug overdose mortality outcomes, while measures related to cannabis dispensaries, substance use treatment, social capital, and family households were negatively associated with drug overdose mortality outcomes. Both positive and negative associations were documented for smoking, uninsurance, healthcare professional shortage status, physicians per capita, unemployment, income, poverty, educational attainment, racial composition, and rurality. Findings within studies also differed by subpopulation (by race/ethnicity, gender, age, or rurality) and the type of drugs involved in overdose.

CONCLUSIONS

The findings of this review provide relatively mixed evidence regarding many county-level predictors of overdose mortality, several of which also vary between subpopulations, supporting the importance of additional research to elucidate pathways through which the county context may shape risk of fatal overdose.

Associations of opioid prescription dose and discontinuation with risk of substance-related morbidity in long-term opioid therapy

ABSTRACT

Efforts to reduce opioid-related harms have decreased opioid prescription but have provoked concerns about unintended consequences, particularly for long-term opioid therapy (LtOT) recipients. Research is needed to address the knowledge gap regarding how risk of substance-related morbidity changes across LtOT and its discontinuation. This study used nationwide commercial insurance claims data and a within-individual design to examine associations of LtOT dose and discontinuation with substance-related morbidity. We identified 194,839 adolescents and adults who initiated opioid prescription in 2010 to 2018 and subsequently received LtOT. The cohort was followed for a median of 965 days (interquartile range, 525-1550), of which a median of 176 days (119-332) were covered by opioid prescription. During follow-up, there were 17,582 acute substance-related morbidity events, defined as claims for emergency visits, inpatient hospitalizations, and ambulance transportation with substance use disorder or overdose diagnoses. Relative to initial treatment, risk was greater within individual during subsequent periods of >60 to 120 (adjusted odds ratio [OR], 1.29; 95% CI, 1.12 to 1.49) and >120 (OR, 1.48; 95% CI, 1.24-1.76) daily morphine milligram equivalents. Risk was also greater during days 1 to 30 after discontinuations than during initial treatment (OR, 1.19; 95% CI, 1.05-1.35). However, it was no greater than during the 30 days before discontinuations, indicating that the risk may not be wholly attributable to discontinuation itself. Results were supported by a negative control pharmacotherapy analysis and additional sensitivity analyses. They suggest that LtOT recipients may experience increased substance-related morbidity risk during treatment subsequent to initial opioid prescription, particularly in periods involving higher doses.

Less Well-Known Consequences of the Long-Term Use of Opioid Analgesics: A Comprehensive Literature Review

BACKGROUND

The adverse effects of short-term opioid analgesics are well known and acknowledged; however, the spectrum of the sequelae of long-term use seems less clear. Some effects may remain undetected but still have the potential to cause harm and reduce patients' quality of life.

OBJECTIVE

To review the literature on the adverse effects of long-term opioid therapy.

METHODS

We performed a quasi-systematic search, analyzing articles published in the MEDLINE database between January 2000 and March 2021 that identified adverse effects of opioids used for chronic pain treatment.

RESULTS

Growing evidence indicates that there are multiple serious adverse effects of opioid treatment. Long-term opioid use may have significant effects on the endocrine, immune, cardiovascular, respiratory, gastrointestinal, and neural systems. Studies show that long-term opioid treatment increases the risk of fractures, infections, cardiovascular complications, sleep-disordered breathing, bowel dysfunction, overdose, and mortality. Opioids may potentially affect cancer development. Most consequences of the long-term use of opioids have been identified in studies of patients with non-malignant pain.

CONCLUSION

Studies indicate that long-term use of opioids increases the risk of drug-related events in a significant number of patients. Clinicians should be aware of these complications associated with prescribing opioids, discuss them with patients, prevent complications, if possible, and diagnose them early and manage adequately. More human studies are needed to assess the risk, including trials with individual opioids, because they have different adverse effect profiles.

Population-Based Study on the All-Cause and Cause-Specific Risks of Mortality among Long-Term Opioid Analgesics Users without Cancer in Taiwan

(1) Background: The prevalence of opioid use in Taiwan increased by 41% between 2002 and 2014. However, little is known regarding the risk of mortality among long-term opioid analgesics users who do not have cancer. This study investigated this mortality risk with an emphasis on the calendar year and patients’ age and sex. (2) Methods: This retrospective cohort study included 12,990 adult individuals without cancer who were long-term users of opioid analgesics and were randomly selected from the data set of Taiwan’s National Health Insurance program from 2000 to 2012. They were then followed up through 2013. Information on the underlying causes of death was retrieved from the Taiwan Death Registry. Age, sex, and calendar year-standardized mortality ratios (SMRs) of all-cause and cause-specific mortality were calculated with reference to those of the general population. (3) Results: With up to 14 years of follow-up, 558 individuals had all-cause mortality in 48,020 person-years (cumulative mortality: 4.3%, mortality rate: 11.62 per 1000 person-years). Compared with the general population, the all-cause SMR of 4.30 (95% confidence interval (95% CI): 3.95–4.66) was significantly higher: it was higher in men than in women, declined with calendar year and age, and was significantly higher for both natural (4.15, 95% CI: 3.78–4.53) and unnatural (5.04, 95% CI: 3.88–6.45) causes. (4) Conclusions: Long-term opioid analgesics use among individuals without cancer in Taiwan was associated with a significantly increased risk of mortality. The notably increased mortality in younger adults warrants attention. Strategies to reduce long-term opioid analgesics use, especially their overuse or misuse, are in an urgent need.

HIV Infection and Depression Among Opiate Users in a US Epicenter of the Opioid Epidemic

Using a mobile research facility, we enrolled 141 opioid users from a neighborhood of Philadelphia, an urban epicenter of the opioid epidemic. Nearly all (95.6%) met DSM-5 criteria for severe opioid use disorder. The prevalence of HIV infection (8.5%) was more than seven times that found in the general population of the city. Eight of the HIV-positive participants (67.0%) reported receiving antiretroviral treatment but almost all of them had unsuppressed virus (87.5%). The majority of participants (57.4%) reported symptoms consistent with major depressive disorder. Severe economic distress (60.3%) and homelessness were common (57%). Polysubstance use was nearly universal, 72.1% had experienced multiple overdoses and prior medication for opioid use disorder (MOUD) treatment episodes (79.9%), but few currently engaged in addiction care. The prevalence, multiplicity and severity of chronic health and socioeconomic problems highlight consequences of the current opioid epidemic and underscore the urgent need to develop integrated models of treatment.

Fatal self-injury in the United States, 1999-2018: Unmasking a national mental health crisis

BACKGROUND

Suicides by any method, plus 'nonsuicide' fatalities from drug self-intoxication (estimated from selected forensically undetermined and 'accidental' deaths), together represent self-injury mortality (SIM)-fatalities due to mental disorders or distress. SIM is especially important to examine given frequent undercounting of suicides amongst drug overdose deaths. We report suicide and SIM trends in the United States of America (US) during 1999-2018, portray interstate rate trends, and examine spatiotemporal (spacetime) diffusion or spread of the drug self-intoxication component of SIM, with attention to potential for differential suicide misclassification.

METHODS

For this state-based, cross-sectional, panel time series, we used de-identified manner and underlying cause-of-death data for the 50 states and District of Columbia (DC) from CDC's Wide-ranging Online Data for Epidemiologic Research. Procedures comprised joinpoint regression to describe national trends; Spearman's rank-order correlation coefficient to assess interstate SIM and suicide rate congruence; and spacetime hierarchical modelling of the 'nonsuicide' SIM component.

FINDINGS

The national annual average percentage change over the observation period in the SIM rate was 4.3% (95% CI: 3.3%, 5.4%; p<0.001) versus 1.8% (95% CI: 1.6%, 2.0%; p<0.001) for the suicide rate. By 2017/2018, all states except Nebraska (19.9) posted a SIM rate of at least 21.0 deaths per 100,000 population-the floor of the rate range for the top 5 ranking states in 1999/2000. The rank-order correlation coefficient for SIM and suicide rates was 0.82 (p<0.001) in 1999/2000 versus 0.34 (p = 0.02) by 2017/2018. Seven states in the West posted a ≥ 5.0% reduction in their standardised mortality ratios of 'nonsuicide' drug fatalities, relative to the national ratio, and 6 states from the other 3 major regions a >6.0% increase (p<0.05).

INTERPRETATION

Depiction of rising SIM trends across states and major regions unmasks a burgeoning national mental health crisis. Geographic variation is plausibly a partial product of local heterogeneity in toxic drug availability and the quality of medicolegal death investigations. Like COVID-19, the nation will only be able to prevent SIM by responding with collective, comprehensive, systemic approaches. Injury surveillance and prevention, mental health, and societal well-being are poorly served by the continuing segregation of substance use disorders from other mental disorders in clinical medicine and public health practice.

FUNDING

This study was partially funded by the National Centre for Injury Prevention and Control, US Centers for Disease Control and Prevention (R49CE002093) and the US National Institute on Drug Abuse (1UM1DA049412-01; 1R21DA046521-01A1).