(CNN)The duration of a prescription may give clues into how long a person ends up using a narcotic painkiller, a new study finds.
The study in the Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report finds that when you use a narcotic painkiller for just one day, you have only a 6% chance of still using that drug a year later. But when that prescription is for eight or more days, your likelihood of using the drug a year later jumps to 13.5%. And although just less than 7% of all prescriptions exceed a month's dosage, using for 31 days or more increases your chances of long-term opioid use to 29.9%.
"The initial prescription a clinician writes has a pretty profound impact on a person's (likelihood) for being a long-term opioid user," said Bradley Martin, co-author of the study and head of the Division of Pharmaceutical Evaluation and Policy at the University of Arkansas for Medical Sciences College of Pharmacy.
Considering that prescription opioids such as oxycodone and hydrocodone were involved in 24% of all drug overdoses in 2015, experts have said, management of prescription drug overdoses is a key element of fighting the opioid epidemic.
"Given how many people are injured or killed by opioids, it's surprising we don't know more basic information, like this information contained in this report," said Dr. Caleb Alexander, co-director of the Johns Hopkins Center for Drug Safety and Effectiveness, who was not involved in the new study.
The authors evaluated and followed 1.2 million patients who received prescriptions for opioid painkillers between 2006 and 2015, except those with cancer, who are frequently prescribed opioids on a long-term basis to manage pain. The data were drawn from the IMS LifeLink database, which uses information from health plans across the nation.
In addition to duration of prescription, the type of narcotic prescribed was an indicator of the odds someone would still be using the drug a year later.
The authors of the study found that long-acting or extended-release opioids, painkillers that have been formulated to provide a stable dosage over a longer period of time, were often an indicator of long-term use. Those patients who received a prescription for an extended-release opioid had a 27.3% chance to still be using it a year later and a 20.5% chance to be using it three years later.
Those who started with certain short-acting opioids, which are formulated to be taken more more frequently over the same period of time as a long-acting opioid, had a 8.9% chance to still be using after one year and a 5.3% chance after three years. When looking only at short-acting hydrocodone and oxycodone, the likelihood of still using a year later dropped to 5.1% and 4.7%, respectively.
Another concern about prescription pills is the fact that painkiller use has been linked to heroin use. According to the National Institute on Drug Abuse, half of all young people who inject heroin started by abusing painkillers. In fact, a quarter of all high school seniors report having used or abused prescription opioids, according to a new report in the journal Pediatrics (PDF).
The CDC study "should give doctors and patients pause. It further underscores the fact that opioids shouldn't be initiated cavalierly," Alexander said.
In 2016, the CDC established guidelines for prescribing narcotics for chronic pain. The bottom line: Non-opioid treatments are preferred methods to manage chronic pain, and opioids should be used only when the benefits outweigh the risks. The recommendations also called on prescribers to limit initial prescriptions to three days or less.
In addition, a handful of states -- Connecticut, Massachusetts, Rhode Island, New York and Maine -- adopted legislation that limits opioid prescriptions to seven days. This year, New Jersey became the strictest, limiting painkiller prescriptions to just five days.