Acupuncture for peripheral joint osteoarthritis: Cochrane systematic review

Abstract

Assessed as up to date: 2008/04/16

Background

Peripheral joint osteoarthritis is a major cause of pain and functional limitation. Few treatments are safe and effective.

Objectives

To assess the effects of acupuncture for treating peripheral joint osteoarthritis.

Search strategy

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2008, Issue 1), MEDLINE, and EMBASE (both through December 2007), and scanned reference lists of articles.

Selection criteria

Randomized controlled trials (RCTs) comparing needle acupuncture with a sham, another active treatment, or a waiting list control group in people with osteoarthritis of the knee, hip, or hand.

Data collection and analysis

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. We calculated standardized mean differences using the differences in improvements between groups.

Main results

Sixteen trials involving 3498 people were included. Twelve of the RCTs included only people with OA of the knee, 3 only OA of the hip, and 1 a mix of people with OA of the hip and/or knee. In comparison with a sham control, acupuncture showed statistically significant, short-term improvements in osteoarthritis pain (standardized mean difference -0.28, 95% confidence interval -0.45 to -0.11; 0.9 point greater improvement than sham on 20 point scale; absolute percent change 4.59%; relative percent change 10.32%; 9 trials; 1835 participants) and function (-0.28, -0.46 to -0.09; 2.7 point greater improvement on 68 point scale; absolute percent change 3.97%; relative percent change 8.63%); however, these pooled short-term benefits did not meet our predefined thresholds for clinical relevance (i.e. 1.3 points for pain; 3.57 points for function) and there was substantial statistical heterogeneity. Additionally, restriction to sham-controlled trials using shams judged most likely to adequately blind participants to treatment assignment (which were also the same shams judged most likely to have physiological activity), reduced heterogeneity and resulted in pooled short-term benefits of acupuncture that were smaller and non-significant. In comparison with sham acupuncture at the six-month follow-up, acupuncture showed borderline statistically significant, clinically irrelevant improvements in osteoarthritis pain (-0.10, -0.21 to 0.01; 0.4 point greater improvement than sham on 20 point scale; absolute percent change 1.81%; relative percent change 4.06%; 4 trials;1399 participants) and function (-0.11, -0.22 to 0.00; 1.2 point greater improvement than sham on 68 point scale; absolute percent change 1.79%; relative percent change 3.89%). In a secondary analysis versus a waiting list control, acupuncture was associated with statistically significant, clinically relevant short-term improvements in osteoarthritis pain (-0.96, -1.19 to -0.72; 14.5 point greater improvement than sham on 100 point scale; absolute percent change 14.5%; relative percent change 29.14%; 4 trials; 884 participants) and function (-0.89, -1.18 to -0.60; 13.0 point greater improvement than sham on 100 point scale; absolute percent change 13.0%; relative percent change 25.21%). In the head-on comparisons of acupuncture with the 'supervised osteoarthritis education' and the 'physician consultation' control groups, acupuncture was associated with clinically relevant short- and long-term improvements in pain and function. In the head on comparisons of acupuncture with 'home exercises/advice leaflet' and 'supervised exercise', acupuncture was associated with similar treatment effects as the controls. Acupuncture as an adjuvant to an exercise based physiotherapy program did not result in any greater improvements than the exercise program alone. Information on safety was reported in only 8 trials and even in these trials there was limited reporting and heterogeneous methods.

Authors' conclusions

Sham-controlled trials show statistically significant benefits; however, these benefits are small, do not meet our pre-defined thresholds for clinical relevance, and are probably due at least partially to placebo effects from incomplete blinding. Waiting list-controlled trials of acupuncture for peripheral joint osteoarthritis suggest statistically significant and clinically relevant benefits, much of which may be due to expectation or placebo effects.

Author(s)

Manheimer Eric, Cheng Ke, Linde Klaus, Lao Lixing, Yoo Junghee, Wieland Susan, van der Windt Daniëlle AWM, Berman Brian M, Bouter Lex M

Summary

Acupuncture for osteoarthritis

This summary of a Cochrane review presents what we know from research about the effect of acupuncture on osteoarthritis.

The review shows that in people with osteoarthritis,

-Acupuncture may lead to small improvements in pain and physical function after 8 weeks.

-Acupuncture may lead to small improvements in pain and physical function after 26 weeks.

We often do not have precise information about side effects and complications. This is particularly true for rare but serious side effects. Possible side effects of acupuncture treatment include minor bruising and bleeding at the site of needle insertion.

What is osteoarthritis and what is acupuncture?

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.

According to the philosophy of traditional acupuncture, energy circulates in 'meridians' located throughout the body.  Pain or ill health happens when something occurs to cause this meridian energy circulation to be blocked. The way to restore health is to stimulate the appropriate combination of acupuncture points in the body by inserting very thin needles.  Sometimes in painful conditions, electrical stimulation along with the needles is also used.  According to acupuncture theory, one way you can tell that acupuncture is relieving pain is that you may feel numbness or tingling, called de qi, where the needle is inserted.

Best estimate of what happens to people with osteoarthritis who have acupuncture:

Pain after 8 weeks:

-People who had acupuncture rated their pain to be improved by about 4 points on a scale of 0 to 20.
-People who received sham acupuncture rated their pain to be improved by about 3 points on a scale of 0 to 20.

-People who received acupuncture had a 1 point greater improvement on a scale of 0-20.  (5% absolute improvement).

Pain after 26 weeks:

-People who had acupuncture rated their pain to be improved by slightly more than 3 points on a scale of 0 to 20.
-People who received sham acupuncture rated their pain to be improved by slightly less than 3 points on a scale of 0 to 20.

-People who received acupuncture had under a 1 point greater improvement on a scale of 0-20.  (2% absolute improvement). 

Physical function after 8 weeks :

-People who had acupuncture rated their function to be improved by about 11 points on a scale of 0 to 68.
-People who received sham acupuncture rated their function to be improved by about 8 points on a scale of 0 to 68.

-People who received acupuncture had about a 3 point greater improvement on a scale of 0-68.  (4% absolute improvement) 

Physical function after 26 weeks :

-People who had acupuncture rated their function to be improved by about 11 points on a scale of 0 to 68.
-People who received sham acupuncture rated their function to be improved by about 10 points on a scale of 0 to 68.

-People who received acupuncture had about a 1 point greater improvement on a scale of 0-68.  (2% absolute improvement)

Reviewer's Conclusions

Implications for practice

The effects of true acupuncture relative to sham do not meet our pre-specified thresholds for clinical relevance. Thus, the effects of acupuncture relative to sham acupuncture are too small to be perceived by participants as beneficial; however, few if any other commonly used treatments for osteoarthritis meet these thresholds for minimal clinically important differences. For example, NSAIDS (relative to an inert placebo) do not meet these thresholds, yet NSAIDs are used regularly by half of all people with painful osteoarthritis. Acupuncture, in contrast, is used by only about 1% of people with osteoarthritis, and most of these people do not use it specifically for treating their osteoarthritis.

The effects of true acupuncture relative to a waiting list control and some of the other active treatment control groups do exceed our thresholds for clinical relevance. The only other non-pharmacological treatment for osteoarthritis with benefits close to or exceeding the thresholds for clinical relevance is exercise, with standardized mean differences of .39 for pain and .31 for function, relative to a non-exercise control group. However, in both cases, sham treatments were not used as controls, so some of the benefits measured may be attributable to expectation or placebo effects. Although exercise cannot be compared with sham exercise, acupuncture can be compared with sham acupuncture, although sham acupuncture may not be an inert placebo. While the comparison of acupuncture with sham, which shows very small benefits of acupuncture at best, is useful for estimating the specific biological effects of acupuncture, it may be less relevant for clinical applications. Rather, the evaluation of the whole package of acupuncture, including both its specific and non-specific components (as is the case with exercise and education), may be of equal or greater clinical relevance. Overall, the studies suggest that people with osteoarthritis find meaningful benefits through acupuncture, although these benefits may be largely mediated through placebo effects.

The fact that few if any OA treatments have specific effects that meet the threshold for clinically relevant benefits should not be interpreted to mean that we simply have no effective treatment for osteoarthritis. Rather, it may be that the threshold for clinical relevance is too high for any individual treatment alone, and that a multidisciplinary approach to OA patient management, with a focus on combining several nonpharmacological therapies is necessary. Some clinicians and patients may consider acupuncture as one treatment option in such a multidisciplinary integrative approach to treating knee osteoarthritis.

The relative benefits of acupuncture compared with other treatments cannot be reliably assessed because there is a scarcity of direct comparisons. Comparing different OA treatments by using indirect comparisons of effect sizes from different meta-analyses can be misleading because of differences in the numbers of studies, comparators used, and characteristics of participants. Indeed, the recent Osteoarthritis Research International recommendations state that at best we can only examine whether there is no overlap of the 95% confidence intervals between the meta-analytic effect sizes of different treatments to see whether there may be differential benefits. And yet because for most OA treatments there are small effect sizes with wide confidence intervals, and differences in point estimates across different meta-analyses evaluating the same treatments, it is unreliable to estimate the relative effects of acupuncture compared to other active treatments using indirect comparisons.

Safety and costs are other considerations. Safety is best determined with large prospective surveys of practitioners, and 3 such surveys show that serious adverse events after acupuncture are rare. There were no adverse events associated with acupuncture in this review, although heterogeneous reporting and relatively small sample sizes limit the usefulness of this safety data. In addition to efficacy and safety, people with OA and their clinicians will also need to consider costs because acupuncture treatment often needs to be paid for out of pocket, at least in part.

Implications for research

Considering the prevalence of knee osteoarthritis and its burden on the health system and society in general and the dearth of safe and effective treatments, it seems warranted to conduct additional RCTs evaluating the cost-effectiveness of acupuncture, as well as its short- and long-term effects relative to other active treatments and shams. Pragmatic comparisons (including cost-effectiveness studies) are now of particular clinical relevance, and some future trials should perhaps shift from sham controls to active controls. Also, future trials might shift focus from the knee to other peripheral joints, for which the current evidence is scarce.

The results of this systematic review may help inform the design of future trials in several ways. First, current RCT results suggest that benefits may attenuate over time, and therefore for future trials that assess long-term outcomes, it may be important to maintain monthly acupuncture treatments in the months prior to the long-term assessment. Second, our sensitivity analysis suggests that electrical stimulation may be associated with better outcomes, and the two sham-controlled trials in this review that used intensive electrical stimulation of all local knee points showed the greatest benefits. While these findings might indicate a superiority of electroacupuncture over needle acupuncture without electrical stimulation, the finding may also be explained by the fact that electroacupuncture is probably more difficult to blind than needle acupuncture and some of the extra benefit seen with electroacupuncture may be due to incomplete blinding or placebo effects. Third, our sensitivity analysis suggests that an adequate number of treatments delivered over a time period of a sufficient duration may be associated with better outcomes. Fourth, acupuncture may elicit a greater placebo effect or meaning response than usual care therapies, particularly among participants who have a preference for acupuncture, and therefore investigators conducting future pragmatic trials that compare acupuncture with other active therapies might consider asking participants about their preferences and expectations (before and after the intervention), and studying the potential effects of pre-treatment preferences on study outcomes. Furthermore, to minimize the recruitment of participants with a preference for acupuncture, advertisements to recruit participants should ideally not specify that acupuncture is one of the treatments being investigated. Fifth and last, our review suggests that skin-penetrating needle shams may be best at insuring blinding success, but that such penetrating shams may also have physiological activity. Future trials should therefore consider the use of non-insertive shams; however, because such non-insertive shams may be less believable to participants, if they are used, their credibility should be tested, certainly before the trial starts, and perhaps also during the trial.

There are at least three large and rigorous ongoing sham-controlled trials, all of which should be published within the next couple of years. The largest of these three trials, which was recently presented at a conference, found no difference between true and sham acupuncture, but found significant differences between both the true and sham acupuncture groups and the waiting list control group. The results of the two other sham-controlled trials currently ongoing will be unlikely to shift the currently very small pooled benefits of acupuncture relative to sham towards the threshold for clinical relevance; however, these ongoing trials, likely to be successfully blinded, will be important to further assess how much of the currently observed benefit of acupuncture relative to sham is due to expectation or placebo effects and how much is due to specific effects of the needle placement. However, the truth about acupuncture effects will always be difficult to assess, even through a systematic review of well-designed and well-reported RCTs. The complexities and potential biases inherent to both the non-acupuncture and sham acupuncture control designs makes it difficult to evaluate the subjective, patient-reported outcomes in peripheral joint osteoarthritis.

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