OUD is described by the CDC as a problematic pattern of opioid use that causes significant impairment or distress. The United States has experienced a sharp increase in the incidence of opiate use disorder over the last 3 decades. In 2020, 91,799 drug overdose deaths occurred in the US and an estimated 2.7 million people ages 12 or older reported having an OUD.1 This corresponds with increased use of both prescription and illicit opioids. The number of overdose deaths due to opioids, including prescription opioids, heroin, and synthetic opioids was 10 times higher in 2021 than in 1999.2
The effect of opioid agonists on mortality:
Santo et al performed a systematic review and meta-analysis of 15 randomized controlled trials (RCT) and 36 primary cohort studies.3 The study found that the risk of all-cause, overdose, suicide, alcohol-related, cancer, and cardiovascular-related mortality was significantly lower for people with opioid dependence during opioid agonist treatment (OAT). The rate of all-cause mortality during OAT was more than half of the rate seen during time out of OAT. The findings were not significantly different when comparing methadone vs buprenorphine. Notably, the all-cause mortality was 6 times higher in the 4 weeks after OAT cessation.
Krawczyk et al studied a total of 48,274 adults admitted to outpatient specialty treatment programs in 2015-16 for primary diagnosis of opioid use disorder in Maryland.4 The study population experienced 371 opioid overdose deaths. Periods in medication treatment were associated with substantially reduced hazard of opioid overdose death compared with periods in non-medication treatment. Periods after discharge from non-medication treatment and medication treatment had similar and substantially elevated risks compared with periods in non-medication treatments. Methadone and buprenorphine were associated with significantly lower overdose death compared with non-medication treatments during care but not after treatment is discontinued.
Pearce et al evaluated outcomes of 55,347 people with opioid use disorder who received OAT between 1 January 1996 and 30 September 2018.5 The all-cause standardized mortality ratio was substantially lower on OAT (4.6) than off OAT (9.7). Retention on OAT was associated with substantial reductions in the risk of mortality for people with opioid use disorder. The protective effect of OAT on mortality increased as fentanyl and other synthetic opioids became common in the illicit drug supply.
Effectiveness of Agonists:
Mattick et al reviewed 31 studies evaluating buprenorphine maintenance compared to placebo and to methadone maintenance in the management of opioid dependence.6 The overall conclusions revealed buprenorphine to be an effective medication in the maintenance treatment of heroin dependence, retaining people in treatment at any dose above 2 mg and suppressing illicit opioid use (at doses 16 mg or greater) based on placebo-controlled trials. However, compared to methadone, buprenorphine retained fewer people when doses are flexibly delivered and at low fixed doses. If fixed medium or high doses are used, buprenorphine and methadone appear no different in effectiveness (retention in treatment and suppression of illicit opioid use).
In a 2009 meta-analysis of 11 studies, Mattick et al evaluated 1969 participants for the effectiveness of methadone maintenance therapy.7 Methadone appeared statistically significantly more effective than non-pharmacological approaches in retaining patients in treatment and in the suppression of heroin use. Methadone was determined to be an effective maintenance therapy intervention for the treatment of heroin dependence as it retains patients in treatment and decreases heroin use better than treatments that do not utilize opioid replacement therapy. It does not show a statistically significant superior effect on criminal activity or mortality.
Klimas et al evaluated the retention rates reported by randomized controlled trials (RCTs) and controlled observational studies that compared methadone to buprenorphine (or buprenorphine-naloxone).8 The overall conclusion stated the meta-analysis of existing RCTs suggests retention in oral fixed-dose opioid agonist therapy with methadone appears to be generally equal to buprenorphine (or buprenorphine-naloxone)
Degenhardt et al examined buprenorphine compared with methadone in the treatment of opioid dependence across a wide range of primary and secondary outcomes.9 The study included 32 RCTs and 69 observational studies comparing buprenorphine and methadone, in addition to 51 RCTs and 124 observational studies that reported on treatment retention with buprenorphine. Evidence from the studies suggest that treatment retention is better for methadone than for sublingual buprenorphine. Comparative evidence on other outcomes examined showed few statistically significant differences and was generally based on small numbers of studies.
Naloxone and Education
Walley et al assessed the impact of state supported overdose education and nasal naloxone distribution (OEND) programs on rates of opioid related death from overdose and acute care utilization.10 OEND was implemented among opioid users at risk for overdose, social service agency staff, family, and friends of opioid users. Communities that implemented OEND had significantly reduced adjusted rate ratios compared with communities with no implementation. Opioid overdose death rates were reduced in communities where OEND was implemented. This study provides observational evidence that by training potential bystanders to prevent, recognize, and respond to opioid overdoses, OEND is an effective intervention.
McDonald et al reviewed 1164 records from 22 observational studies regarding the effectiveness of take-home naloxone programs.11 Using Bradford Hill criteria, they found epidemiologic evidence that these programs reduced overdose mortality among participants and have a low rate of adverse events.
Patient preferences and service needs
Friedrichs et al reviewed 25 trials that were conducted between 1986 and 2014.12 In their evaluation, two studies found that patients with substance use disorder preferred to be actively involved in treatment decisions and three studies showed that matching patients to their preferences resulted in a reduction of substance use. However, several studies found no statistically significant effect. The findings related to shared decision making differed across patient populations and optional therapeutic techniques.
Friedman et al analyzed prospective data from a US cohort of addiction treatment patients who reported service needs beyond core rehabilitative services (n = 3103).13 Matching comprehensive services to needs during treatment improved their drug use outcomes in the year following treatment relative to the year before. The strongest effects on drug use improvement were from matching needs for vocational and housing services.
Assessment and Treatment Plan:
In the 2020 focused update, the American Society of Addiction Medicine (ASAM) made the following recommendations regarding the initial evaluation of patients beginning treatment for opiate use disorder14:
- Completion of the patient’s medical history should include screening for concomitant medical conditions including psychiatric disorders, infectious diseases, acute trauma, and pregnancy.
- A physical examination should be completed as a component of the comprehensive assessment process.
- Initial laboratory testing should include a complete blood count, liver enzyme tests, and tests for TB, hepatitis B and C, and HIV.
- Patients being evaluated for OUD, and/or for possible medication use in the treatment of OUD, should undergo (or have completed) an assessment of mental health status and possible psychiatric disorders.
In the 2014 publication by the ASAM entitled ‘Standards of Care for the Addiction Specialist Physician’15 the following recommendation was made regarding therapeutic alternatives, ‘The addiction specialist physician discusses and offers all available clinically indicated psychosocial and pharmacological therapies to all patients, assisting the patient to collaborate in clinical decision-making, assuring that the patient is aware of therapeutic alternatives. This will include the advantages and disadvantages of medications for addiction, taking into consideration cost, availability, and potential for diversion. When pharmacotherapies are part of the treatment plan, the addiction specialist physician decides with the patient about the setting for treatment, assuring appropriate dosage and duration for the medication, monitors adherence, and assures psychosocial therapies occur throughout the treatment process.’