Oral or transdermal opioids for osteoarthritis of the knee or hip
Abstract
Background
Osteoarthritis is the most common form of joint disease and the leading cause of pain and physical disability in the elderly. Opioids may be a viable treatment option if patients suffer from severe pain or if other analgesics are contraindicated. However, the evidence about their effectiveness and safety is contradictory.
Objectives
To determine the effects on pain and function and the safety of oral or transdermal opioids as compared with placebo or no intervention in patients with osteoarthritis of the hip or knee.
Search methods
We searched CENTRAL, MEDLINE, EMBASE, and CINAHL (up to 28 July 2008), checked conference proceedings, reference lists, and contacted authors.
Selection criteria
Studies were included if they were randomised or quasi‐randomised controlled trials that compared oral or transdermal opioids with placebo or no treatment in patients with osteoarthritis of the knee or hip. Studies of tramadol were excluded. No language restrictions were applied.
Data collection and analysis
We extracted data in duplicate. Standardised mean differences (SMDs) and 95% confidence intervals (CI) were calculated for pain and function, and risk ratios for safety outcomes. Trials were combined using inverse‐variance random‐effects meta‐analysis.
Main results
Ten trials with 2268 participants were included. Oral codeine was studied in three trials, transdermal fentanyl and oral morphine in one trial each, oral oxycodone in four, and oral oxymorphone in two trials. Overall, opioids were more effective than control interventions in terms of pain relief (SMD ‐0.36, 95% CI ‐0.47 to ‐0.26) and improvement of function (SMD ‐0.33, 95% CI ‐0.45 to ‐0.21). We did not find substantial differences in effects according to type of opioid, analgesic potency (strong or weak), daily dose, duration of treatment or follow up, methodological quality of trials, and type of funding. Adverse events were more frequent in patients receiving opioids compared to control. The pooled risk ratio was 1.55 (95% CI 1.41 to 1.70) for any adverse event (4 trials), 4.05 (95% CI 3.06 to 5.38) for dropouts due to adverse events (10 trials), and 3.35 (95% CI 0.83 to 13.56) for serious adverse events (2 trials). Withdrawal symptoms were more severe after fentanyl treatment compared to placebo (SMD 0.60, 95% CI 0.42 to 0.79; 1 trial).
Authors' conclusions
The small to moderate beneficial effects of non‐tramadol opioids are outweighed by large increases in the risk of adverse events. Non‐tramadol opioids should therefore not be routinely used, even if osteoarthritic pain is severe.
PICOs
Plain language summary
Opioids for osteoarthritis
This summary of a Cochrane review presents what we know from research about the effect of opioids on osteoarthritis.
The review shows that in people with osteoarthritis:
‐ Opioids moderately improve pain or physical function.
‐ Opioids probably cause side effects. However, we do not have precise information about rare but serious side effects.
What is osteoarthritis and what are opioids?
Osteoarthritis (OA) is a disease of the joints, such as your knee or hip. When the joint loses cartilage, the bone grows to try and repair the damage. Instead of making things better, however, the bone grows abnormally and makes things worse. For example, the bone can become misshapen and make the joint painful and unstable. This can affect your physical function or ability to use your knee.
Opioids are powerful pain‐relieving substances that are used for the pain of cancer or osteoarthritis. Some examples of opioids are codeine‐containing Tylenol® (1, 2, 3 and 4), hydromorphone (Dilaudid), oxycodone (Percocet, Percodan), morphine and others. They can be taken in a pill form, as an injection, or as a patch placed on the painful area.
Best estimate of what happens to people with osteoarthritis who take Opioids
Pain
‐ People who took opioids rated improvement in their pain to be about 3 on a scale of 0 (no pain) to 10 (extreme pain) after 1 month.
‐ People who took a placebo rated improvement in their pain to be about 2 on a scale of 0 (no pain) to 10 (extreme pain) after 1 month.
Another way of saying this is:
‐ 35 people out of 100 who use opioids respond to treatment (35%).
‐ 31 people out of 100 who use placebo respond to treatment (31%).
‐ 4 more people respond to treatment with opioids than with placebo (difference of 4%).
Physical Function
‐ People who took opioids rated improvement in their physical function to be about 2 on a scale of 0 (no disability) to 10 (extreme disability) after 1 month.
‐ People who took a placebo rated improvement in their physical function to be about 1 on a scale of 0 (no disability) to 10 (extreme disability) after 1 month.
Another way of saying this is:
‐ 29 people out of 100 who use opioids respond to treatment (29%).
‐ 26 people out of 100 who use placebo respond to treatment (26%).
‐ 3 more people respond to treatment with opioids than with placebo (difference of 3%).
Side effects
‐ 23 people out of 100 who used opioids experienced side effects (23%).
‐ 15 people out of 100 who used a placebo experienced side effects (15%).
‐ 7 more people experienced side effects with opioids than with placebo (difference of 7%).
