Four years after the initiation of treatment, 16 percent of those who received opioids at the start were still on opioids, whereas only 5 percent of those who were treated with non-opioids initially were on opioids after four years. They concluded that those who were initially treated with opioids had a higher rate of surgery and a greater chance of being on opioids four years later but no significant change in overall outcome (Radcliff et al., 2013).