Drug Use Disorders and Mortality
In 2000, approximately 193,000 deaths worldwide were linked to illicit drug use.44 Mortality rates among persons using illicit drugs are more than 10 times greater than those in the general population matched for age and gender.45 However, different drugs carry different mortality risks, with primary opioid users having a higher risk than users of other drugs.46-49 A recent review of cohort studies of cocaine users concluded that SMRs are about 4-8 times higher among cocaine users than their age- and gender-matched peers in the general population.50
Young men who use illicit drugs are particularly at risk for premature mortality, especially those who have used drugs for a decade or more.45 Although men account for 75% of drug-related deaths, the SMRs associated with illicit drug use among women are higher than those of men. In other words, female illicit drug users are substantially more likely to die relative to nonusing women than are male illicit drug users in comparison to nonusing men probably because the mortality rate among women in the general population is lower than that for men. Although drug overdose (especially among opioid and cocaine users) is a primary cause of death among illicit drug users, suicide and such diseases as HIV, HCV, and HBV, as well as trauma (e.g., from violence and motor vehicle accidents) also are prevalent causes.45
Regarding treated samples, the fact that the mortality rate among individuals treated for drug addiction is higher than that for the general population51 should come as no surprise. In one study, mortality among heroin injection drug users who had public drug treatment was 13 times greater than that in the general population.52 In another study, 4-year mortality in a sample of patients in drug treatment programs was about six times higher than that for the age-matched general population.53 Individuals hospitalized for opioid-related disorders were at greater risk of dying (SMR = 5.7) than those hospitalized for methamphetamine (4.7), cannabis (3.9), cocaine (3.0), or alcohol (3.8) disorders.54
Fortunately, treatment, especially prolonged, stable treatment, is linked to lower mortality.45 For example, an early study observed that although patients in methadone maintenance had a risk of mortality that was eight times that of the general population, the risk among untreated, heroin-dependent “street addicts” was substantially higher (63 times the expected rate).55 Similarly, Zanis and Woody56 found that although the mortality rate among patients remaining in methadone treatment was 1% over 12 months, 8% of patients who dropped out or were unfavorably discharged from methadone maintenance died over the same period.
Among individuals hospitalized for drug addiction and followed for 8 years, mortality averaged 2.2% annually.48 Heroin users who did not enter methadone treatment had the highest annual mortality rate (4.4%), whereas no deaths occurred over the 8 years among HIV-negative methadone patients. Importantly, Peles, Schreiber, and Adelson57 found that individuals who stayed in methadone treatment 1 year or more survived longer compared to those who left treatment after less than a year. Whereas overdose was the most prevalent cause of death among those who dropped out of methadone treatment, cancer was the most frequent cause of death for those who remained in treatment.52,57,58 Similarly, in a retrospective study, Bartu and colleagues46 found that drug users who had received specialty drug treatment were less likely to die than were those who never received treatment or who had discontinued treatment at least 6 months previously.
As was the case for persons treated for AUDs, inpatient care for drug use disorders is associated with a higher mortality risk relative to outpatient care.59 These findings may be explained in part by the greater severity of disorder among persons receiving inpatient treatment and by the fact that individuals seem especially vulnerable to overdose in the first month after leaving inpatient treatment.58,60
As was the case for persons with AUDs, better drug use outcomes following treatment are associated with a reduced mortality risk. For example, among treated opioid-dependent individuals, even though they continued to have an SMR seven times higher than the general population, those with stable abstinence reduced their risk of premature death by 56% relative to patients who continued to use drugs.61 Similar findings have emerged for studies of injection drug users.62