Trends in overdose deaths from drug misuse in Europe: what do the data tell us?

Real-world patterns of opioid therapy initiation in Spain, 2012-2018: A population-based, retrospective cohort study with 957,080 patients and 1,509,488 initiations

Introduction: Europe has seen a steady increase in the use of prescription opioids, especially in non-cancer indications. Epidemiological data on the patterns of use of opioids is required to optimize prescription. We aim to describe the patterns of opioid therapy initiation for non-cancer pain and characteristics of patients treated in a region with five million inhabitants in the period 2012 to 2018. Methods: Population-based retrospective cohort study of all adult patients initiating opioid therapy for non-cancer pain in the region of Valencia. We described patient characteristics at baseline and the characteristics of baseline and subsequent treatment initiation. We used multinominal regression models to identify individual factors associated with initiation. Results: A total of 957,080 patients initiated 1,509,488 opioid treatments (957,080 baseline initiations, 552,408 subsequent initiations). For baseline initiations, 738,749 were with tramadol (77.19%), 157,098 with codeine (16.41%) 58,436 (6.11%) with long-acting opioids, 1,518 (0.16%) with short-acting opioids and 1,279 (0.13%) with ultrafast drugs. When compared to tramadol, patients initiating with short-acting, long-acting and ultrafast opioids were more likely to be older and had more comorbidities, whereas initiators with codeine were more prone to be healthier and younger. Treatments lasting less than 7 days accounted for 41.82% of initiations, and 11.89% lasted more than 30 days. 19.55% of initiators with ultrafast fentanyl received more than 120 daily Morphine Milligram Equivalents (MME), and 16.12% of patients initiating with long-acting opioids were prescribed more than 90 daily MME (p < 0.001). Musculoskeletal indications accounted for 65.05% of opioid use. Overlap with benzodiazepines was observed in 24.73% of initiations, overlap with gabapentinoids was present in 11.04% of initiations with long-acting opioids and 28.39% of initiators with short-acting opioids used antipsychotics concomitantly. In subsequent initiations, 55.48% of treatments included three or more prescriptions (vs. 17.60% in baseline initiations) and risk of overlap was also increased. Conclusion: Opioids are initiated for a vast array of non-oncological indications, and, despite clinical guidelines, short-acting opioids are used marginally, and a significant number of patients is exposed to potentially high-risk patterns of initiation, such as treatments lasting more than 14 days, treatments surpassing 50 daily MMEs, initiating with long-acting opioids, or hazardous overlapping with other therapies.

The impact of opiate substitution treatment on mortality risk in drug addicts: a natural experiment study

Background

Opiate substitution treatment (OST) is the main treatment for people addicted to heroin and other opioid drugs. However, there is limited information on how the delivery of this treatment affects mortality risk.

Objectives

To investigate the associations of mortality risk with periods during treatment and following cessation of treatment, medication type, co-prescription of other medication and dosing regimens during titration and detoxification. The trends with time of prescribed medication, dose and treatment duration were also explored.

Design

Prospective longitudinal observational study.

Setting

UK primary care between 1998 and 2014.

Participants

A total of 12,780 patients receiving methadone, buprenorphine or dihydrocodeine.

Main outcome measures

All-cause mortality relating to 657 deaths and drug-related poisoning relating to 113 deaths.

Data sources

Clinical Practice Research Datalink with linked information on cause of death from the Office for National Statistics.

Results

For both outcomes, the lowest mortality risk was observed after 4 weeks of treatment and the highest risk was observed in the first 4 weeks following cessation of treatment [e.g. for drug-related poisoning, incidence rate ratio (IRR) 8.15, 95% confidence interval (CI) 5.45 to 12.19]. There was evidence that the treatment period risks varied with OST medication. The largest difference in risk was for the first 4 weeks of treatment for both outcomes, with patients on buprenorphine being at lower risk than those on methadone (e.g. for drug-related poisoning, IRR 0.08, 95% CI 0.01 to 0.48). The co-prescription of benzodiazepines was associated with linearly increasing the risk of drug-related deaths by dose (IRR 2.02, 95% CI 1.66 to 2.47), whereas z-drugs (zolpidem, zopiclone and zaleplon) were associated with increased risk of both all-cause (IRR 1.83, 95% CI 1.59 to 2.12) and drug-related (IRR 3.31, 95% CI 2.45 to 4.47) mortality. There was weak evidence that higher initial and final doses were associated with increased all-cause mortality risk. In the first 4 weeks of treatment, the risk increased by 4% for each 5-mg increment in methadone dose (1-mg increase in buprenorphine) (hazard ratio 1.04, 95% CI 1.00 to 1.09). In the first 4 weeks after treatment ceased, a similar increment in final dose increased the risk by 3% (hazard ratio 1.03, 95% CI 0.99 to 1.07). There were too few deaths to evaluate the effects on drug-related poisoning. The proportion of OST patients receiving buprenorphine increased between 1998 and 2006. Median treatment duration was consistently shorter for buprenorphine than for methadone for each year studied (overall median duration of 48 and 106 days, respectively).

Limitations

As this was an observational study, the possibility remains of bias from unmeasured factors, which covariate adjustment and inverse probability weighting can eliminate only partially.

Conclusions

Using buprenorphine as an alternative to methadone may not reduce mortality overall despite resulting in lower IRRs from shorter treatment duration. Clinical guidance needs to consider strengthening warnings about the co-prescription of a range of drugs for OST patients.

Future work

Our analyses need to be replicated using other clinical data sets in the UK and in other countries. New interventions and trials are required to investigate improving the retention of OST patients in primary care.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

A cross-national analysis of the association between years of implementation of opioid substitution treatments and drug-related deaths in Europe from 1995 to 2013

Data at the individual-level provide evidence that opioid substitution treatment (OST) programs protect against mortality for opioid dependent populations. Prior research has not examined the merits of national implementation of opioid substitution programs for reducing mortality at the country-level. This study elucidates longitudinal associations between country-level implementation of opioid substitution treatment programs on mortality rates of drug related deaths (DRD) from 1995 to 2013 in 30 European nations. Cases of DRD were measured using National Definitions for each country from official sources of data. Preliminary analysis of dispersion of cases of DRD using means and variances justified use of the negative binomial regression model with a population offset. Year and country-level fixed effects negative binomial regression models investigated the association between years of implementation of methadone maintenance therapy (MMT), OST in prison, and high dose buprenorphine treatment (HDBT) implementation and mortality rates from drug related deaths after adjusting for unemployment rates, heroin seizures and per capita expenditures on health. Beta coefficients were converted to Incidence Rate Ratios (IRR) and standard errors bootstrapped using non-parametric methods to adjust for bias (SD_bs). The mean mortality rate of DRD was 1.81 from 1995 to 2013. In adjusted models, each additional year of MMT (IRR = .61, SD = .04, p < .001; SD_bs = .08, p < .001), prison OST (IRR = .90, SD = .01, p < .001; SD_bs = .02, p < .001), and HDBT (IRR = .09, SD = .02, p < .001; SD_bs = .02, p < .01) was significantly associated with lower rates of DRDs after adjusting for country and year fixed effects. Implementation of OST programs in the general population and in prison settings may have protected against mortality from drug use at the country-level in Europe from 1995 to 2013.

Higher methadone doses are associated with lower mortality in patients of opioid dependence in Taiwan

Optimal methadone dosage and service profile is challenging in treatment of opioid dependence. This study explores the impact of methadone dosage on the mortality of opioid-dependent patients in methadone maintenance therapy by using a large-scale and continual supervised dosing registry information system. Database of nationwide enrolled opioid-dependent patients at methadone clinics in Taiwan during 2006-2008 was assessed. The relative risk of age, sex, marital status, HIV infection and methadone dosage were analyzed by Cox regression analysis. Among all of the 33,549 recruited patients, the crude mortality rate was 134.78/10,000 person-years, and the standardized mortality ratio was 4.68. A dose-response relationship of higher- vs. lower-dosage groups on the risk of mortality risk was observed (adjusted HR = 0.68, P = 0.016). In further sub-grouping analysis, this trend was more significant in HIV positive patients, in subgroup of patients who continuously staying in MMT, and in subgroup of patients who re-enter MMT. This dosage effect is not significantly seen in patients receiving MMT more than 365 days. Further exploration of other treatment-related factors may be important for understanding the long-term treatment outcome of opioid addiction patients.

Influence of war on quantitative and qualitative changes in drug-induced mortality in Split-Dalmatia County, Croatia

Aim

To study drug-induced mortality and characteristics of overdose deaths in the war (1991-1995), pre-war (1986-1990), and post-war period (1996-2000) in Split-Dalmatia County.

Methods

We retrospectively searched through Databases of the Department of Forensic Medicine, University Hospital Split, the national register of death records, the archives of the Split-Dalmatia County Police, and the Register of Treated Drug Addicts of the Croatian National Institute of Public Health, covering the period from 1986 to 2000, according to drug poisoning codes IX and X of the International Classification of Diseases. The indicators were statistically analyzed.

Results

There were 146 registered drug-induced deaths, with 136 (93%) deceased being men. The median age of all cases was 27 years (interquartile range 8). Most of them were single (70.6%), unemployed (44.6%), and secondary school graduates (69.2%). In the war period, there were 4.8 times more deaths than in the pre-war period (P = 0.014), and in the post-war period there were 5.2 times more deaths than in the pre-war period (P = 0.008). The most common site of death was the deceased person’s home. The toxicological analyses showed that 59 (61%) deaths were heroin related, alcohol use was found in 62 cases (42.5%), and multi-substance use was found in more than a half of the cases. In 133 (91.1%) cases, deaths were classified as unintentional, whereas 13 (8.9%) were classified as suicides.

Conclusion

The war, along with other risk factors, contributed to unfavorable developments related to drug abuse in Split-Dalmatia County, including the increase in the drug-induced mortality rate.

Trends and pattern of drug abuse deaths in Maryland teenagers

The Office of the Chief Medical Examiner of Maryland recorded a total of 149 drug abuse deaths of teenagers aged 13-19 years between 1991 and 2006. Of these deaths, 96 (64.4%) were caused by the use of narcotic drugs only, 29 (19.5%) by both narcotics and cocaine, four (2.7%) by both narcotics and methylenedioxymethamphetamine, six (4.0%) by cocaine only, and 14 (9.4%) by volatile substances (e.g., butane, Freon, nitrous oxide, and propane). The annual death rate from drug abuse for teenagers increased from 1.4 deaths per 100,000 population in 1991 to 2.7 deaths per 100,000 population in 2006 (chi-square test for time trend, p<0.01). The increase in teenager drug abuse deaths occurred in 1999 and since has remained at a higher rate. Further analysis revealed that the increase in drug abuse deaths was attributable to a large degree to narcotic drugs, particularly heroin/morphine and methadone, and was confined to teenagers residing in the suburban and rural areas.

Problem drug use, drug misuse and deliberate self-harm: trends and patient characteristics, with a focus on young people, Oxford, 1993-2006

BACKGROUND

Drug misuse is related to self-harm and suicide. However, relatively little is known about deliberate self-harm (DSH) in patients with drug problems and whether drug misuse by DSH patients is increasing.

METHODS

We used data collected by the Oxford Monitoring System for Attempted Suicide to study the characteristics of DSH patients with drug problems who presented to the general hospital in Oxford between 1993 and 2006, and who underwent psychosocial assessment at their first presentation in the study period. We also studied trends in problem drug use and drugs misused over this period.

RESULTS

During the 14-year study period, 11,426 patients presented of whom 9,248 underwent psychosocial assessment and it was known whether or not they had a drug problem. Problem drug use was present in 805/9,248 (8.7%) patients. Problem drug use was more common in males (13.6%) than in females (5.3%). Problem drug users were younger, more likely to be socially disadvantaged, to have a personality disorder and comorbid alcohol problems and to have a further episode of DSH within a year. Problem drug use in young females was associated with higher suicidal intent scale (SIS) scores. During the study period, problem drug use and drug misuse increased in females, but not in males. Cannabis and cocaine misuse increased with time.

CONCLUSIONS

Provision of help for DSH patients with problem drug use is particularly challenging due to their complex social and clinical characteristics and increased risk of further self-harm, suicide and accidental death. It may require extensive liaison between different services. The increasing misuse of drugs by female DSH patients and the higher SIS scores of young females are of concern.

Risk of death during and after opiate substitution treatment in primary care: prospective observational study in UK General Practice Research Database

OBJECTIVE

To investigate the effect of opiate substitution treatment at the beginning and end of treatment and according to duration of treatment.

DESIGN

Prospective cohort study. Setting UK General Practice Research Database.

PARTICIPANTS

Primary care patients with a diagnosis of substance misuse prescribed methadone or buprenorphine during 1990-2005. 5577 patients with 267 003 prescriptions for opiate substitution treatment followed-up (17 732 years) until one year after the expiry of their last prescription, the date of death before this time had elapsed, or the date of transfer away from the practice.

MAIN OUTCOME MEASURES

Mortality rates and rate ratios comparing periods in and out of treatment adjusted for sex, age, calendar year, and comorbidity; standardised mortality ratios comparing opiate users' mortality with general population mortality rates.

RESULTS

Crude mortality rates were 0.7 per 100 person years on opiate substitution treatment and 1.3 per 100 person years off treatment; standardised mortality ratios were 5.3 (95% confidence interval 4.0 to 6.8) on treatment and 10.9 (9.0 to 13.1) off treatment. Men using opiates had approximately twice the risk of death of women (morality rate ratio 2.0, 1.4 to 2.9). In the first two weeks of opiate substitution treatment the crude mortality rate was 1.7 per 100 person years: 3.1 (1.5 to 6.6) times higher (after adjustment for sex, age group, calendar period, and comorbidity) than the rate during the rest of time on treatment. The crude mortality rate was 4.8 per 100 person years in weeks 1-2 after treatment stopped, 4.3 in weeks 3-4, and 0.95 during the rest of time off treatment: 9 (5.4 to 14.9), 8 (4.7 to 13.7), and 1.9 (1.3 to 2.8) times higher than the baseline risk of mortality during treatment. Opiate substitution treatment has a greater than 85% chance of reducing overall mortality among opiate users if the average duration approaches or exceeds 12 months.

CONCLUSIONS

Clinicians and patients should be aware of the increased mortality risk at the start of opiate substitution treatment and immediately after stopping treatment. Further research is needed to investigate the effect of average duration of opiate substitution treatment on drug related mortality.

Missing targets on drugs-related deaths, and a Scottish paradox

The 10-year drug strategy for England and Wales was published in February 2008. It dropped drugs-related deaths (DRDs) as a key performance indicator. Scotland retained a necessary strong focus on DRDs. Scotland's DRDs numbered 1006 in 2000-02 and 1009 in 2003-05. The previous Scottish administration's claim that its number of current injectors had decreased substantially between 2000 and 2003 implied, paradoxically, that their DRD rate would have to have increased. Worse was to come: Scotland's DRDs had increased to 876 in 2006+2007. We analyse UK's DRDs by sex and age-group to reveal temporal trends (2000-02 versus 2003-05 versus 2006+2007) with different public health and epidemiological implications. We also address the above Scottish paradox and assess, by age-group, how consistent Scotland's 876 DRDs in 2006+2007 are with Scottish injectors' DRD rate in 2003-05 of around 1 per 100 injector-years. Public health success in the UK in reducing DRDs at younger ages should not be overshadowed by the late consequence in terms of older-age DRDs of UK's injector epidemics; in the early 1980s in Scotland, and late 1980s in England and Wales. Targets for reducing DRDs should pay heed to UK's injector epidemics.

Hepatitis C infection among injecting drug users in England and Wales (1992-2006): there and back again?

Changes in hepatitis C virus (HCV) prevalence from 1992 to 2006 were examined by using 24,311 records from unlinked anonymous surveillance of injecting drug users in England and Wales. Bayesian logistic regression was used to estimate annual prevalence, accounting for changing recruitment patterns (age, gender, injecting duration, geographic region, interactions) and the sensitivity and specificity of different oral fluid testing devices. After controlling for these differences, the authors found that the adjusted HCV prevalence decreased from 70% (95% credible interval: 62, 78) in 1992 to 47% (95% credible interval: 43, 51) in 1998 before rising again to 53% (95% credible interval: 48, 58) in 2006. Women injecting drug users had a higher HCV risk than did men (odds ratio = 1.50, 95% credible interval: 1.31, 1.73). Two regions (London and North West) had a markedly higher HCV prevalence than did the rest of England and Wales. Among individuals who had injected for less than 1 year, the adjusted HCV prevalence in 2006 was higher than that in 1992 (28% vs. 19%, respectively). HCV infection can be prevented. The public health challenge in England and Wales is to increase action in order to regain a downward trend in HCV risk and the benefit that has been lost since 1998.

Assessing IDU prevalence and health consequences (HCV, overdose and drug-related mortality) in a primary care trust: implications for public health action

BACKGROUND

We report on an exercise to estimate the prevalence of injecting drug use (IDU) and associated harms in a single primary care trust.

METHODS

Covariate capture-recapture methods to estimate (i) IDU prevalence; respondent driven sampling to measure (ii) prevalence of HCV and HIV and record linkage to measure (iii) mortality risk.

RESULTS

(i) The overall estimated number of IDU was 5540 (95% confidence interval, CI: 4710-6780) for all cases and 3280 (95% CI: 1940-4610) for cases matched to primary care register, i.e. a prevalence of 2.2 and 1.3% aged 15-54, respectively. (ii) The prevalence of HCV, hepatitis B and HIV was: 53, 32 and 0.7%. Over 70% of IDU in Bristol reported having at least one vaccination for HBV; more than half of those who were HCV positive were undiagnosed. (iii) The all-cause and overdose mortality rates for IDU were 0.75 and 0.4% respectively; and the standardized mortality ratio was 7.8 (95% CI: 5.4-10.8).

CONCLUSION

Locally specific and useful intelligence on injecting and its health consequence can be generated to inform local public health action, and may contribute information to validate national prevalence estimates.