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Acupuncture for chronic headache in primary care: large, pragmatic, randomised trial

BMJ 2004; 328 doi: https://doi.org/10.1136/bmj.38029.421863.EB (Published 25 March 2004) Cite this as: BMJ 2004;328:744

Rapid Response:

Acupuncture as prophylactic treatment for 'chronic headache'

Dear editors,

Vickers et al conclude that "acupuncture leads to persisting and
clinically relevant benefits for patients with chronic headache"(1). We
compliment the authors for their laudable attempt in conducting such a
complicated pragmatic trial but we are inclined to arrive at opposite
conclusions. We feel that the observed differences versus control were
clinically irrelevant, and that the control group was "doing much worse"
than to be expected rather than the acupuncture group "doing better" .

The primary efficacy score (weekly headache score) is unusual, not
recommended by accepted guidelines(2), and not validated with respect to
reliability, reproducibility and clinical relevance. Its calculation is
not explained unambiguously. As we understand it, headache severity was
assessed four times daily on a 0-5 score. Thus, the maximum weekly
headache score is 7 x 4 x 5 = 140.

The weekly headache score improved after one year from 24.6 to 16.2
in the acupuncture group and from 26.7 to 22.3 in the usual care group.
This is a difference of 4.6 on a total scale of 140 (3.3 %). We are
uncertain as to the clinical relevance of this statistically significant
difference.

The average baseline weekly headache scores were 24.6 and 26.7 and
the (calculated) average weekly number of days with headache is around 4.
From this we would calculate that the maximum average headache severity
per day was 26.7 / 4 days / 4 assessment points = 1.7. This is less than
grade 2, which was defined as "mild headache that can be ignored at
times". Such a low severity is extremely unlikely for migraine
headaches(3)

The lack of a clinically relevant improvement is also reflected in
the minute or even statistically barely significant improvements for the
secondary outcome measures. For example, after one year the difference in
reduction of number of headache days per month is 1.8 days with an average
headache severity of less than grade 2. Is this a clinically relevant
gain? Similarly, out of 9 SF-36 health status scales, only one showed a
statistically significantly improvement.

We are also unsure as to whether the one year primary endpoint
assessment was based on patients continuing to assess their headaches
scores 4 times daily for 12 months, or on a one week assessment at the end
of the year. The first would be highly unlikely, the second is
statistically unsatisfactory.

Another major problem seems to be the lack of a sham procedure in the
control group and the unblinded design with "open randomisation". The
authors describe that suitable patients were actively invited to
participate in this study, but then 50% were randomised to no treatment
other than usual care. In contrast to blinded controlled studies where
patients do not know that they have been assigned to "no treatment", here
patients were fully aware and may have been greatly disappointed,
potentially resulting in a negative placebo effect. This could explain the
remarkably low response in the control group of only 15% at three and 12
months for both the weekly headaches score and the proportion of patients
with at least a 50% reduction in days with headache. This compares
unfavourably with the usual placebo effects of 20-40%(2) found in migraine
prophylaxis studies. The acupuncture responder rate of 30% is also much
lower than is usually seen for active treatments in migraine prophylactic
trials and more in line of what is seen for placebo rates(2).

Finally, we are concerned that 6% of the study patients did not have
migraine, but instead tension-type headache. Because of the fundamentally
different pathophysiological basis of both disorders, this doesn't seem to
help to understand why acupuncture would work in the first place. Why not
excluding these patients from the analysis? The new work places
complementary therapies squarely on the agenda for research, but can in no
way be taken as proof for the effect of acupuncture in the treatment of
migraine. Moreover, it certainly should not be a basis for funding
widespread uncontrolled application of this approach.

Guus G. Schoonman,
Research fellow
Department of Neurology
Leiden University Medical Centre, Leiden, The Netherlands

Natalie J. Wiendels,
Research fellow
Department of Neurology
Leiden University Medical Centre, Leiden, The Netherlands

Peter J. Goadsby,
Professor of Neurology
Institute of Neurology
The National Hospital for Neurology and Neurosurgery, Queen Square London
UK

Michel D. Ferrari,
Professor of Neurology
Department of Neurology
Leiden University Medical Centre, Leiden, The Netherlands

References

1. Vickers AJ, Rees RW, Zollman CE, McCarney R, Smith CM, Ellis N et
al. Acupuncture for chronic headache in primary care: large, pragmatic,
randomised trial. BMJ 2004;328:744.

2. Tfelt-Hansen P, Block G, Dahlof C, Diener HC, Ferrari MD, Goadsby
PJ et al. Guidelines for controlled trials of drugs in migraine: second
edition. Cephalalgia 2000;20:765-86.

3. Goadsby PJ, Lipton RB, Ferrari MD. Migraine- current
understanding and treatment. N.Engl.J.Med. 2002; 346:257-70.

Competing interests:
None declared

Competing interests: No competing interests

13 April 2004
Guus G Schoonman
Research fellow
Natalie J. Wiendels, Peter J. Goadsby, Michel D. Ferrari
Department of Neurology, Leiden University Medical Centre (2333 ZA, Leiden, the Netherlands)