People addicted to opioid painkillers are nearly six times more likely to die than healthy individuals, according to a comprehensive new study. Opioid addicts were also found to have a higher risk of death than alcoholics or people hooked on methamphetamine, marijuana or other drugs.
The study by Canada’s Centre for Addiction and Mental Health (CAMH), is the largest North American study to compare mortality rates among different drug users. It tracked records of more than 800,000 individuals hospitalized in California with drug dependence between 1990 and 2005. Of that group, more than 188,000 people died over the 15-year study period.
“These are not occasional, recreational drug users, but people who have been hospitalized for drug dependence,” said study co-author Dr. Stephen Kish, a senior scientist at CAMH.
The abuse of prescription painkillers is a major health problem in the both the U.S. and Canada. The U.S. Centers for Disease Control and Prevention estimates over 15,000 Americans die annually from prescription opiate overdoses — more than from cocaine and heroin combined.
Researchers say the risk of death for opioid addicts was 5.71 times higher than healthy individuals of the same age, gender and race. That means if 10 individuals in the general population died, then over the same period there would be 57 deaths among people addicted to opioids, which includes prescription drugs such as oxycodone, as well as heroin.
Methamphetamine addicts had the second highest risk of death (4.67 times the general population), followed by patients addicted to cannabis (3.85), alcohol (3.83) and cocaine (2.96). Alcohol dependence was related to the highest number of deaths overall.
“One reason for undertaking this study was to examine whether methamphetamine posed a particular threat to drug users, as it has been called ‘America’s most dangerous drug,'” says CAMH scientist Dr. Russell Callaghan, who led the study. “The risk is high, but opioids are associated with a higher risk.”
“One surprising finding was the high rate of death among cannabis users,” said Callaghan. “There could be many potential reasons, including the fact that they may have other chronic illnesses such as psychiatric illnesses or AIDS, which can also increase the risk of death.”
Alcohol abuse affected the most patients, with 166,482 deaths and 582,771 hospitalizations of alcoholics over the study period. In the methamphetamine group, there were 4,122 deaths out of 74,139 hospitalizations, and for opioids, 12,196 deaths out of 67,104 hospitalizations.
Specific causes of death were not examined in this study, so the deaths may not have been directly caused by drugs but were due to injuries, infectious disease or other reasons. The researchers are now looking at mortality causes for each drug group – hoping to learn why women have a higher risk of death for alcohol, cocaine and opioids than males.
To calculate mortality rates, researchers examined hospital records of all California inpatients with a diagnosis of methamphetamine, alcohol, opioid, cannabis or cocaine-related disorders from 1990-2005. The inpatient records were then matched to death records from the California Vital Statistics Database and adjusted for age, sex and race. The study is available online in the journal Drug and Alcohol Dependence.