Background: Recommended pain treatments for osteoarthritis (OA) and chronic low back pain (CLBP) are suboptimal, and limited information is available regarding patterns of pharmacotherapy among patients with these conditions.
Aims: Evaluate patterns of therapy switching, augmentation, and discontinuation after treatment initiation with select pain medications in patients with OA and CLBP.
Methods: Using the U.K. The Health Improvement Network (THIN) database, OA and CLBP patients newly prescribed (index-event) nonselective nonsteroidal anti-inflammatory drugs (NS-NSAIDs), cyclooxygenase-2 inhibitors (Cox-2s), acetaminophen, tramadol and weak or strong opioids were selected. Descriptive statistics, Kaplan-Meier analyses, and COX proportional hazards models were used to evaluate patterns of changes in pharmacotherapy during the 12-month postindex period.
Results: Rates of therapy switching, augmentation, and discontinuation, respectively, were significantly different (all P values<0.0001) across the evaluated medication cohorts for both OA and CLBP patients. Discontinuation rates in OA patients were 91.9% (NS-NSAIDs), 86.9% (Cox-2s), 91.4% (acetaminophen), 89.7% (tramadol), 93.2% (weak opioids), and 84.3% (strong opioids); and in CLBP patients were 97.2% (NS-NSAIDs), 94.0% (Cox-2s), 95.0% (acetaminophen), 92.8% (tramadol), 97.0% (weak opioids), and 86.8% (strong opioids). The rates of switching (range 30.0% to 59.6%) and augmentation (range 7.5% to 15.2%) were lower. Estimated probability evaluations suggested that two-thirds of patients who switched, augmented, or discontinued therapy did so within the first couple of months, and a majority did so within 6-months of treatment initiation.
Conclusions: This study demonstrates that therapy switching and discontinuation of select pain medications were common among OA and CLBP patients in the U.K. and may result from inadequate pain relief or undesirable side effects.
© 2011 The Authors. Pain Practice © 2011 World Institute of Pain.