‘Sliding Cupping Therapy’ for Psoriasis … or: HOW TO CHEAT WITH SEEMINGLY RELIABLE RESEARCH

I am sure that many of my readers have no idea what ‘Slinding Cupping Therapy’ is. It is a TCM therapy that, according to the authors of this paper, receives much appreciation for treating plaque psoriasis. This study was designed to test the hypothesis that sliding cupping therapy is non-inferior to narrowband ultraviolet B (NBUVB) therapy in improving disease severity in patients with plaque psoriasis.

This prospective trial recruited 60 patients with plaque psoriasis who were randomized to receive either sliding cupping intervention or NBUVB treatment. The cup was moved 30 times for each skin lesion until the target skin area turned purple. The initial dose (mJ/cm²) of ultraviolet radiation b (UVB) was determined based on sun-reactive skin types I through VI, which ranged from 300 mJ/cm² to 800 mJ/cm². Both treatments were performed 3 times per week for 8 weeks. The primary endpoint was the percentage reduction in Psoriasis Area and Severity Index (PASI) score at week 8, with secondary endpoints, including Physician’s Global Assessment (PGA), body surface area, visual analogue scale scores, and quality of life measures.

The total response rates were 69% (18/26) and 79% (19/24) for patients receiving sliding cupping intervention and those receiving NBUVB treatment, respectively, which showed no significant difference (P = .526). The PASI scores, body surface area, and PGA were reduced in patients with plaque psoriasis at W0, W4 and W8 after either sliding cupping intervention or NBUVB treatment (P <.001), and these reductions were not significantly different between the patients receiving sliding cupping intervention and those receiving NBUVB treatment at W0, W4, W8, and W12. At W8, the mean percentage reduction in PASI was 62.4% (95% CI, 54.9–69.8) in the sliding cupping group and 66.9% (95% CI, 59.6–74.2) in the NBUVB group, with no significant difference between groups. The total response rates were 69.23% (18/26) and 79.17% (19/24), respectively (P = .526). Patients receiving sliding cupping intervention and those receiving NBUVB treatment did not show statistically significant differences in these outcomes at W0, W4, W8, and W12 (P >.05).

The authors concluded that the overall results suggest that sliding cupping therapy exhibits statistically similar efficacy and safety profiles as NBUVB treatment, especially at 8 weeks after treatment.

Sliding cupping therapy is a form of cupping in which cups producing mild suction are placed on oiled skin and then moved along the body surface, generating a “reverse massage” that lifts rather than compresses the subcutaneous tissues. The negative pressure is thought to increase local blood flow and lymphatic drainage, reduce perceived muscle tension, and temporarily improve range of motion, though high‑quality clinical evidence for most claimed benefits remains limited.

The treatment is used mainly by massage therapists, physiotherapists, and TCM practitioners in musculoskeletal and sports‑rehab settings, as well as in wellness and spa‑oriented clinics; it is commonly applied to the back, shoulders, neck, limbs, and along fascial lines or acupuncture meridians, often for pain, stiffness, “trigger‑point”‑type tension, and post‑exercise recovery. The popularity of this therapy is best characterised as a niche within broader cupping and fascial‑release practice rather than a mainstream standard treatment.

The new study is a text-book example of how to mislead people with seemingly reliable research. The fact that it was grossly under-powered – and not the effectiveness of the sliding cupping therapy – is obviously the cause of the lack of a difference between the effective therapy (NBUVB) and the sliding quackery.

Let me give you an example: say, we compare antibiotics (A) to homeopathy (H) as treatments for bacterial pneumonia. We treat 10 patientsin each group, and 8 of them recover in group A within a week, while in the H-group the amount is 6 (many patients recover even without an effective treatment). We run statistical tests which tell us that the difference is not significant. Thus we falsely conclude that homeopathy is as effective as antibiotics in the treatment of pneumonia. The 2 treatments were, in fact, not equal but the lack of power of the small study failed to detect the existing difference.

It seems rather obvious to me that a similar thing has happened with the above study. Its authors are to be congratulated for cheating so slyly that neither the editors nor the reviewers of the journal ‘Medicine’ managed to see through their simple litte trick.