Opioid users exhibit worse baseline knee osteoarthritis, faster degenerative progression
Patients with knee osteoarthritis who use opioids showed worse baseline structural degeneration and faster progression and had greater quality of life loss compared with controls, according to data published in Arthritis Research & Therapy.
“Treatment of KOA symptoms with opioids is not recommended, as opioids do not sufficiently reduce pain or disability, compared to placebo, but are associated with a broader spectrum of common side effects, including nausea, constipation, dizziness, somnolence and addiction,” Jannis Bodden, MD, of the University of California, San Francisco, and colleagues wrote. “Moreover, a higher mortality rate among KOA patients receiving tramadol for pain control has been reported.”
“Furthermore, a randomized trial that assessed treatment-related effects of opioids and non-steroidal anti-inflammatory drugs reported an association between the use of transdermal fentanyl and radiographic KOA progression over 12 weeks,” they added. “However, most previous studies suffer from a low external validity, adherent to in vitro designs, and the aforementioned in-patient trial used radiographs to measure outcomes, which have been shown to be inferior to magnetic resonance imaging, in particular in early stages of the degenerative disease.”
To examine the links between opioid use and magnetic resonance-based structural joint degeneration and symptoms, Bodden and colleagues conducted cross-sectional and longitudinal analyses of patients with knee OA from the Osteoarthritis Initiative. For their cross-sectional cohort, the researchers included 181 patients with baseline opioid use and available right knee magnetic resonance data. For the longitudinal cohort, they included 79 patients with baseline opioid use and available right knee magnetic resonance data who continued opioid use for at least 1 year between baseline and 4-year follow-up.
Participants were frequency matched 1:2 to non-opioid users. The researchers obtained whole-organ magnetic resonance imaging scores (WORMS), including a total summation score and sub-scores for cartilage and menisci, as well as bone marrow abnormalities and subchondral cyst-like lesions. They also reported on patients’ Knee Injury Osteoarthritis Outcomes score (KOOS) symptoms, quality of life (QOL) and pain at baseline and follow-up. The researchers used linear regression models to analyze associations between baseline and longitudinal findings.
Determining that pain could affect the observations, the researchers also conducted a sensitivity analysis for the longitudinal findings.
All analyses were adjusted for sex, BMI, age, race and Kellgren-Lawrence grade, they wrote.
According to the researchers, opioid users demonstrated greater structural degeneration at baseline, with a WORMS total summation score coefficient of 7.1 (95% CI, 5.5-8.8), as well as a greater increase of degeneration over 4 years (4.7; 95% CI, 2.9-6.5), compared with controls. Additionally, patients who used opioids experienced greater increases in cartilage and meniscus scores, compared with controls (P .001). This finding was consistent after adjusting for baseline pain (P .002).
All baseline KOOS scores were lower among opioid users, compared with controls (P < .001). Meanwhile, QOL loss was greater in opioid users, when adjusted for baseline KOOS pain, with a change of –6.9 (95% CI, –11.6 to –2.1).
“Despite the use of opioids, baseline symptom and pain control were worse in opioid users compared to controls,” Bodden and colleagues wrote. “Loss of QOL was more rapid in opioid users, when adjusted for baseline pain scores, further questioning long-term opioid use, particularly in view of major adverse effects associated with this medication.”
“Strong associations between the continued use of opioids and progression of knee structural degeneration were found that withstood adjustments for baseline Kellgren-Lawrence grade and baseline pain scores,” they added. “However, findings may in part be related to a confounding bias. Thus, further studies are needed to determine, if opioid use itself imposes a risk for KOA progression.”