Therapy switching, augmentation, and discontinuation in patients with osteoarthritis and chronic low back pain.
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.


OBJECTIVE
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.
Avalon Health Solutions, Inc., Philadelphia, Pennsylvania, USA. mgore@avalonhealthsolutions.com
Mugdha
M
Gore
Alesia B
AB
Sadosky
Douglas L
DL
Leslie
Kei-Sing
KS
Tai
Paul
P
Emery
D000082:Acetaminophen / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage*; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage*; D015331:Cohort Studies; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D017116:Low Back Pain / Q000188:drug therapy*; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D010003:Osteoarthritis / Q000188:drug therapy*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D006113:United Kingdom
D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid; D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors; D000082:Acetaminophen