Effectiveness of self-management of dry and wet cupping therapy for low back pain: A systematic review and meta-analysis

Low back pain is a significant global problem that affects 70% of the adult population at least once in life, resulting in costs estimated at $134.5 billion in the United States. Conventional treatments include medication, physical therapy, and surgery, but each has limitations and side effects. Cupping therapy, an ancient complementary medicine practice, has gained interest as a therapeutic alternative. This systematic review and meta-analysis, the first to categorically distinguish between dry and wet cupping, investigated the efficacy of each modality in the treatment of low back pain.

The researchers conducted a comprehensive search of five electronic databases, identifying 656 initial studies. After a rigorous selection process, 10 randomized clinical trials involving 690 participants were included in the final analysis. Dry cupping involves only the application of cups with vacuum-induced suction, while wet cupping adds small skin incisions before suction, allowing extraction of a small amount of blood. The methodology used validated self-report scales: the Visual Analog Scale (VAS), the Present Pain Intensity (PPI), and the Oswestry Disability Index (ODI) to measure pain and quality of life.

Results revealed important differences between the two modalities. Wet cupping demonstrated a significant reduction in pain intensity measured by the PPI scale (p < 0.01), while dry cupping did not show a significant difference in pain reduction on the VAS (p = 0.19). Both modalities, however, significantly improved patients' quality of life as measured by the ODI (p < 0.01). Meta-regression identified that the number of treatment sessions was significantly associated with results, suggesting that more sessions provide greater benefits.

The proposed mechanism for the efficacy of wet cupping involves the removal of potentially harmful substances such as cholesterol, free radicals, and heavy metals through bloodletting, similar to the effects of therapeutic phlebotomy. The negative pressure common to both modalities may activate the gate control theory of pain and stimulate the neuro-endocrine-immune system. Treatment protocols varied across studies, with durations of 1 to 4 weeks and 1 to 8 sessions. Application sites included primarily BL-22 to BL-26 in the lumbar region and Ashi points (tender points).

Most studies used 40-120 cc disposable cups with retention times of 3-15 minutes. Study limitations include high heterogeneity across trials (I² > 50%), indicating a lack of standardization in treatment protocols. No study directly compared dry versus wet cupping, limiting conclusions about relative superiority. The difficulty of blinding due to the visible marks left by cups represents another methodological challenge.

Methodological quality varied across studies, with a mean score of 6 ± 2.3 on the PEDro scale. Clinical implications suggest that cupping therapy may be a safe complementary therapeutic option for low back pain, with the wet modality being more effective for pain reduction and both improving quality of life. The choice between modalities should consider patient preferences, practitioner experience, and specific treatment goals. Future research should focus on protocol standardization, direct comparisons between modalities, and investigation of mechanisms of action to strengthen the evidence base for cupping therapy in low back pain management.