BY SARAH OWENS
Patients with polyneuropathy who took opioids continuously for at least 90 days had no improvement in functional status and had a higher risk of adverse events, including overdose, compared to patients who had a shorter duration of opioid use, according to a new study published in the May 22 online edition of JAMA Neurology.
Short-term trials have suggested that opioids can be effective for treating non-cancer pain, but data from long-term trials are less substantial, and long-term opioid use has been linked with a higher risk of opioid use disorders. Still, opioids are commonly prescribed to treat neuropathic pain associated with polyneuropathy, a prevalent disorder in the elderly, despite rising concerns about an opioid-related morbidity pandemic.
"Our results suggest unintended consequences of long-term opioid therapy when it is used for or in the setting of polyneuropathy," the study authors, led by E. Matthew Hoffman, DO, PhD, a resident in adult neurology at the Mayo Clinic School of Graduate Medical Education in Rochester, MN, wrote.
For the study, researchers retrospectively analyzed a cohort of participants in the Rochester Epidemiology Project living in Olmsted County, MN, who received prescriptions between January 1, 2006 and December 31, 2010; patients were followed through November 25, 2016.
They found that among 2,892 patients with polyneuropathy and 14,435 controls, the patients with polyneuropathy were significantly more likely to receive long-term opioids than controls (18.8 percent vs. 5.4 percent, respectively). Among patients with polyneuropathy, those with long-term opioid use had no improvement in functional status markers, and in fact had several markers that were somewhat poorer, including reliance on gait aids (adjusted odds ratio, 1.9; 95% CI, 1.4-2.6), even after adjusting to account for medical comorbidities.
Additionally, of the 1,993 patients with polyneuropathy who were prescribed opioids, patients who received long-term opioid therapy (one or multiple consecutive opioid prescriptions resulting in ≥90 days of continuous use) were significantly more likely to experience an adverse event, including depression, opioid dependence, or opioid overdose, to those who were on opioid therapy for a shorter duration.
The findings, the study authors concluded, show that long-term opioid therapy "appears to increase the risk of adverse outcomes without benefiting functional status" among patients with polyneuropathy. The findings "should be considered by physicians counseling patients with neuropathic pain who are considering opioid analgesic therapy, as well as by authors of guidelines, policy, and consensus statements," they concluded.
The researchers noted several limitations to their study. Among them were the retrospective study design; that they used administrative codes, which may be subject to error, to ascertain polyneuropathy and to identify adverse outcomes; and a dose effect could not be determined because daily morphine equivalents were not calculated.
For more on the safety and efficacy of opioids for neurological conditions, read bit.ly/NT-Opioids.
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