Trial results do not support opioid therapy for back or OA pain
medwireNews: Results of the SPACE trial suggest that opioids do not offer superior pain relief to nonopioid medications for patients with chronic back pain or osteoarthritis (OA).
As reported in JAMA, the SPACE (Strategies for Prescribing Analgesics Comparative Effectiveness) investigators randomly assigned patients with moderate-to-severe chronic back pain or hip or knee OA pain despite analgesic use to receive opioid or nonopioid treatment regimens for 1 year.
Both groups were given multiple treatment options – chosen based on the assigned group and considerations including comorbidities and patient preference – delivered in a three-step process. The 119 participants in the opioid group were given immediate-release morphine, hydrocodone/acetaminophen, or immediate-release oxycodone in the first step, followed by sustained-action morphine or oxycodone in step two, and transdermal fentanyl in step three.
For the 119 patients in the nonopioid group, the first step was acetaminophen or nonsteroidal anti-inflammatory drugs, followed by adjuvant oral medications (nortriptyline, amitriptyline, or gabapentin) and topical agents (capsaicin or lidocaine) in step two. The final step involved drugs requiring prior authorization from the treatment center (pregabalin and duloxetine) and tramadol.
Improvements in pain-related function, as measured by the Brief Pain Inventory (BPI) interference scale, were not significantly different between the two groups at the 12-month follow-up, with mean scores decreasing from 5.4 points at baseline to 3.4 points at 12 months for the opioid group, and from 5.5 to 3.3 points in the nonopioid group.
Pain intensity at 12 months was significantly worse in the opioid group, with mean BPI severity scores of 4.0 versus 3.5 points in the nonopioid group, and patients receiving opioids experienced significantly more medication-related adverse events, at a mean of 1.8 versus 0.9 events.
The only secondary outcome favoring opioids was anxiety symptoms, with patients in the opioid group having significantly better mean scores on the 7-Item Generalized Anxiety Disorder Questionnaire at 12 months (2.5 vs 2.8 points). However, the researchers note that the clinical importance of this finding is “uncertain” given the small magnitude of the difference between the groups and the low baseline level of anxiety among study participants.
“Overall, opioids did not demonstrate any advantage over nonopioid medications that could potentially outweigh their greater risk of harms,” summarize Erin Krebs (Minneapolis Veterans Affairs Health Care System, Minnesota, USA) and fellow SPACE investigators.
And they conclude that the results “do not support initiation of opioid therapy for moderate to severe chronic back pain or hip or knee osteoarthritis pain.”
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