Stimulated by Wu et al 2023.
SR – systematic reviewkey to acronyms
IF – impact factor
RCT – randomised controlled trial
CBT – cognitive behaviour therapy
THI – tinnitus handicap inventory
PTA – pure tone average
dB – decibel (a logarithmic scale of sound level)
Well, I was struggling a bit to find something interesting this week, so delayed choosing and got on with other tasks. Then on Sunday morning, the latest paper out on PubMed was this large SR on tinnitus in the American Journal of Otolaryngology (IF 2.873).
There have been a few previous meta-analyses,[2–4] including one in Acupuncture in Medicine, but none as extensive as this one, which includes 34 RCTs with 3086 patients. The prior reviews included 11, 8, and 5 RCTs each. The number reducing with advancing years – the opposite of what you might expect of course.
With this sort of discrepancy in the number of included trials, you need to check the search, inclusion, and exclusion criteria. The most recent of the other meta-analyses was clearly different in scope, examining acupuncture plus physical and mental interventions, such as music therapy and CBT.
The other two seemed similar in their searches and inclusion criteria apart from the finish dates of the searches of course. So, it is hard to explain why the current, largest review, does not include the older papers written in English and based outside China. In fact, all but one of the RCTs in the current review are from China and written in Chinese. Whilst it is useful to have a summary of this literature, it is curious that almost all the trials from outside China are either explicitly excluded or missed.
The primary outcome used in the current paper was THI, which has 25 items and a maximum score of 100. The pooled data from 19 comparisons and >1000 patients shows a mean reduction in THI of just over 8 points (percent). This is similar in size to the pooled data for THI in one of the previous meta-analyses, but it does not strike me as being large enough to be clinically relevant, since the difference between the midpoint of each of the 5 grades of severity on the THI is 20 points.
Most outcomes are subjective for this condition, but PTA was measured in 7 trials and over 500 patients. Audiograms are not totally objective since they rely on the patients’ perceptions of pure tones, but they are likely to be more so than a simple rating of effectiveness. The pooled data showed an improvement in PTA of just over 5dB, which is about half the sound intensity of breathing or a ticking watch. So, again, not too impressive, but 5dB more than I might have expected.
It is interesting to note that the one paper included from outside China was a clear outlier in the forest plot for the THI outcomes, with a mean benefit of almost 3 times the average. It is also intriguing to note that the PTA outcome in this paper showed absolutely no effect for acupuncture over sham.
Frankly, it is all rather unconvincing, but let us just pretend that there is a real effect of acupuncture in reducing the actual perceived volume of tinnitus. Could it be that the spontaneous output from dysfunctional hair cells in the cochlear is amplified in a similar way to other sensory inputs to the CNS, and that that amplification can be reduced by a course of acupuncture? If this is the case, tinnitus may be another item that I am forced to add the list of conditions and symptoms I treat.
1 Wu Q, Wang J, Han D, et al. Efficacy and safety of acupuncture and moxibustion for primary tinnitus: A systematic review and meta-analysis. Am J Otolaryngol 2023;44:103821. doi:10.1016/j.amjoto.2023.103821
2 Liu F, Han X, Li Y, et al. Acupuncture in the treatment of tinnitus: a systematic review and meta-analysis. Eur Arch Otorhinolaryngol 2016;273:285–94. doi:10.1007/s00405-014-3341-7
3 Huang K, Liang S, Chen L, et al. Acupuncture for tinnitus: a systematic review and meta-analysis of randomized controlled trials. Acupunct Med 2021;39:264–71. doi:10.1177/0964528420938380
4 Li Y, Sang D, Wu Z, et al. Systematic Evaluation of the Efficacy of Acupuncture Associated with Physical and Mental Intervention when Treating Idiopathic Tinnitus and the Improvement of Tinnitus Symptoms. Comput Math Methods Med 2022;2022:6764909. doi:10.1155/2022/6764909
5 Kuzucu I, Karaca O. Acupuncture Treatment in Patients with Chronic Subjective Tinnitus: A Prospective, Randomized Study. Med Acupunct 2020;32:24–8. doi:10.1089/acu.2019.1367
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