1. In this pragmatic, randomized controlled trial, opioids did not result in better pain management or function compared to non-opioid treatments for patients with chronic pain.
2. Opioids resulted in more medication-related symptoms than non-opioid treatments.
Evidence Rating Level: 2 (Excellent)
Study Rundown: Chronic pain remains one of the most difficult conditions to treat in medicine, and with rising rates of opioid abuse, there has been much scrutiny as to their usefulness in treating chronic pain. Despite this, there has yet to be a randomized trial comparing opioid to non-opioid treatments that measures long term pain severity, function, and quality of life outcomes. In this pragmatic, randomized controlled trial of Minnesota VA patients with knee or back osteoarthritis, non-opioid therapies decreased pain intensity more than opioids to a moderate though significant degree and neither pain-related functioning nor health-related quality of life differed between groups after 1 year of treatment. In addition, there were more medication-related symptoms in the opioid group compared to the non-opioid group, though the rate of adverse events were similar between groups. Subgroup analysis by location of pain was similar to analysis of the whole.
Though the pragmatic nature of the trial has certain weaknesses, namely increased uncontrolled variables such as non-pharmacological pain control and lack of blinding, the strength of analyzing patients under real-world conditions greatly strengthens the conclusions of the study. The major weakness lies in the generalizability of the study results, as VA patients are not always representative of other populations, especially in terms of gender. Still, the high retention rate of subjects and strong design greatly support the assertion that opioid treatments may not be the most suitable for chronic musculoskeletal pain.
In-Depth [randomized controlled trial]: A total of 240 patients (98% follow-up rate) from 62 Minnesota VA primary care clinicians were randomized to receive opioid or non-opioid treatment for chronic pain due to back or knee osteoarthritis for 12 months in the Strategies for Prescribing Analgesics Comparative Effectiveness (SPACE) trial. Patients were excluded if they were already on long-term opioid therapy, had contraindications to either treatment including substance use disorder, and had conditions that could interfere with a 12-month assessment, such as life expectancy less than 12 months. Patients were encouraged to seek out other non-pharmacological pain treatments, and patients with depression or PTSD were not excluded. Using the Brief Pain Inventory scores, patients who received non-opioid treatment displayed better BPI pain severity ratings than those who received opioids (difference 0.5; CI95 0.0 to 1.0). The two groups were comparable for pain-related function (difference 0.1; -0.5 to 0.7), physical health-related quality of life (difference -1.3; CI95 -3.8 to 1.3), and mental health-related quality of life (difference 0.7; CI95 -2.4 to 3.8). Opioids were associated with a higher rate of adverse events (difference 0.9; CI95 0.3 to 1.5) but no significant differences in adverse events or misuse measures (p > 0.5). Post-hoc tests for interaction of pain location and treatment were non-significant (p > 0.5) and adjusting for baseline smoking status as a sensitivity analysis did not change the associations.
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