Comparative pain reduction of oral non-steroidal anti-inflammatory drugs and opioids for knee osteoarthritis: systematic analytic review.

OBJECTIVE:

Summarize the comparative effectiveness of oral non-steroidal anti-inflammatory drugs (NSAIDs) and opioids in reducing knee osteoarthritis (OA) pain.

METHODS:

Two reviewers independently screened reports of randomized controlled trials (RCTs), published in English between 1982 and 2015, evaluating oral NSAIDs or opioids for knee OA. Included studies were at least 8 weeks duration, conducted in Western Europe, the Americas, New Zealand, or Australia, and reported baseline and follow-up pain using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain subscale (0-100, 100-worst). Effectiveness was evaluated as reduction in pain, accounting for study dropout and heterogeneity.

RESULTS:

Twenty-seven treatment arms (nine celecoxib, four non-selective NSAIDs [diclofenac, naproxen, piroxicam], eleven less potent opioids [tramadol], and three potent opioids [hydromorphone, oxycodone]) from 17 studies were included. NSAID and opioid studies reported similar baseline demographics and efficacy withdrawal rates; NSAID studies reported lower baseline pain and toxicity withdrawal rates. Accounting for efficacy-related withdrawals, all drug classes were associated with similar pain reductions (NSAIDs: -18; less potent opioids: -18; potent opioids: -19). Meta-regression did not reveal differential effectiveness by drug class but found that study cohorts with a higher proportion of male subjects and worse mean baseline pain had greater pain reduction. Similarly, results of the network meta-analysis did not find a significant difference in WOMAC Pain reduction for the three analgesic classes.

CONCLUSION:

NSAIDs and opioids offer similar pain relief in OA patients. These data could help clinicians and patients discuss likely benefits of alternative analgesics.