|The "cups" come in various forms and sizes... and no, there's no meta-analysis yet that can tell you what the optimal size and form for the treatment of a given disease / problem would be ;-)|
With Phelps strongly believing in the practice, it is quite obvious that it would have worked its alleged recovery magic irrespective of whether the increased blood flow to the cupped area has any local or systemic health effects whic allegedly range from anti-viral therapy to blood pressure management - you call that "placebo effect".
From a science perspective, though, there is some preliminary evidence that Phelps' trust is / was not totally misplaced, though - here's an overview of what we know...
- Initial evidence of cupping to treat chronic neck pain (Lauche. 2013) - Chronic neck pain is a major public health problem with very few evidence-based complementary treatment options.
It would thus be great, if the positive results of a 2013 study that tested the efficacy of 12 weeks of a partner-delivered home-based cupping massage, and compared it to the same period of progressive muscle relaxation in patients with chronic non-specific neck pain, could be reproduced in a more tightly controlled setting.
Figure 1: Cupping vs. PMR home-treatment in a 12-week study in patients w/ chronic neck pain (Lauche. 2013).
After treatment, both groups showed significantly less pain compared to baseline however without significant group differences. Significant effects in favor of cupping massage were only found for wellbeing and pressure pain thresholds.
"In conclusion, cupping massage is no more effective than progressive muscle relaxation in reducing chronic non-specific neck pain. Both therapies can be easily used at home and can reduce pain to a minimal clinically relevant extent. Cupping massage may however be better than PMR in improving well-being and decreasing pressure pain sensitivity but more studies with larger samples and longer follow-up periods are needed to confirm these results" (Lauche. 2013), the Lauche and colleagues from the University of Duisburg-Essen conclude.
- Preliminary evidence of a reduction of symptoms of osteoarthritis (Teut. 2012) - Scientists from the Charité University Medical Center in Berlin investigated the effectiveness of cupping in relieving the symptoms of knee osteoarthritis (OA) in a two-group, randomized controlled exploratory pilot study.
Image 1: Much in contrast to most other studies, the osteoarthritis didn't use "cups" and heating, but this adaptable silicone cup at the knee (Teut. 2012).
In addition, the subjects' use of Paracetamol was documented within the 4-week treatment period. Analyses were performed by analysis of covariance adjusting for the baseline value for each outcome.
Figure 2: Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score and Visual Analogue Scale (VAS) for pain intensity after 4 and 12 weeks of cupping or control (Teut. 2012).
"In this exploratory study dry cupping with a pulsatile cupping device relieved symptoms of knee OA compared to no intervention. Further studies comparing cupping with active treatments are needed," Teut et al. conclude and forget to mention that everything could be placebo... after all, simply not doing anything is not a valid / significant "treatment" to evaluate the effects of cupping. This and the fact that the dosage of pain-killers are things you should keep in mind when evaluating the study results.
|"Wet" = bloody cupping - Geez!|
- Promising effects in chronic low back pain, systematic review says (Huang. 2016) - It's just published as a letter, but the systematic review Huang and colleagues from Taiwan argue that "the research results show that cupping therapy is promising for pain control and improvement of quality of life, and minimises the potential risks of treatment" (ibid.). Huang et al. base this assessment on their review of one randomised controlled trial (RCT, level I evidence), six non-RCTs (level II evidence), 20 case reports (level IV evidence) and two mechanism-based reasoning studies (see Table 1):
Table 1: Overview of studies with levels I and II evidence Huang et al. (2016) included in their review.
It should not be forgotten, though, that the evidence is rather preliminary than water-tight. Accordingly, Huang et al. are 100% right, when they demand that "further studies are needed to determine the potential role of cupping therapy in the treatment of low back pain" (Huang. 2016).
|Table 2: Estimate effect of cupping for pain management (all types of diseases) from 16 included trials (Cao. 2014).|
- A plethora of additional possible benefits (Cao. 2012) - While pain management appears to be the closest to being a proven benefit of cupping, the literature that was reviewed among others by Cao, Li and Liu lists other purported benefits.
The scientists from the University of Western Sydney and the Beijing University of Chinese Medicine managed to identify the impressive number of 135 RCTs published from 1992 through 2010; studies that were generally of low methodological quality, but investigated diseases ranging from herpes zoster, facial paralysis (Bell palsy), cough and dyspnea, over acne, lumbar disc herniation, to cervical spondylosis.
Figure 3: Types of cupping therapy used in the studies in the meta-analysis (Cao. 2012).
- Akhtar, Jamal, and M. Khalid Siddiqui. "Utility of cupping therapy Hijamat in Unani medicine." Indian J Trad Knowl 7.4 (2008): 572-4.
- Cao, Huijuan, Xun Li, and Jianping Liu. "An updated review of the efficacy of cupping therapy." PLoS One 7.2 (2012): e31793.
- Cao, Huijuan, et al. "Cupping therapy for acute and chronic pain management: a systematic review of randomized clinical trials." Journal of Traditional Chinese Medical Sciences 1.1 (2014): 49-61.
- Huang, Chia-Yu, Mun-Yau Choong, and Tzong-Shiun Li. "Effectiveness of cupping therapy for low back pain: a systematic review." Acupuncture in Medicine (2013): acupmed-2013.
- Kawthar, Abeer Mohammed. "Effect of compining antilipids drugs with wet cupping on lipid blood level." (2007).
- Lauche, Romy, et al. "Effectiveness of home-based cupping massage compared to progressive muscle relaxation in patients with chronic neck pain—A randomized controlled trial." PloS one 8.6 (2013): e65378 [FFT]
- Lee, Myeong Soo, et al. "Cupping for hypertension: a systematic review." Clinical and experimental hypertension 32.7 (2010): 423-425.
- Teut, Michael, et al. "Pulsatile dry cupping in patients with osteoarthritis of the knee–a randomized controlled exploratory trial." BMC complementary and alternative medicine 12.1 (2012): 1.
- Zarei, Mohammad, et al. "The efficacy of wet cupping in the treatment of hypertension." ARYA Atheroscler (2012): S145-S148.