Table 2.

Meta-analysis of outcomes and level of evidence

Variable	Overall effect						Studies (N)	Sample size (N)	Level of evidence
	MD	95% CI	P values	I2	P values	Statistical method
Cupping versus waitlist (sole)
Pain (VAS)	−2.42	−3.98 to –0.86	0.002	93	<0.00001	Random inverse variance	5	241	Very low
Pain (VAS) omitting one study	−1.48	−1.86 to –1.10	<0.00001	0	0.57	Random inverse variance	4	181	–
Disability (NDI)	−4.34	−6.77 to –1.91	0.0005	6	0.35	Random inverse variance	3	141	Low
QoL  (physical component of SF-36)	2.46	−0.36 to 5.29	0.09	24	0.27	Random inverse variance	3	141	Low
QoL  (mental component of SF-36)	5.32	0.83 to 9.80	0.02	32	0.23	Random inverse variance	3	141	Low
Cupping versus active control (sole)
Pain (VAS)	−0.89	−1.42 to –0.37	0.0009	88	<0.00001	Random inverse variance	9	870	Low
Pain (VAS) of dry cupping	−1.48	−1.86 to –1.10	<0.00001	0	0.57	Random inverse variance	3	149	–
Pain (VAS) of wet cupping	−0.70	−1.32 to –0.07	0.03	92	<0.00001	Random inverse variance	6	721	–
Pain (VAS) of wet cupping omitting one study	−0.49	−0.78 to –0.20	0.0008	35	0.19	Random inverse variance	5	521	–
Disability (NDI)	−4.36	−8.67 to –0.04	0.05	62	0.05	Random inverse variance	4	213	Very low
QoL (SF-36)  (physical component of SF-36)	5.44	2.09 to 8.78	0.001	7	0.30	Random inverse variance	2	109	Low
QoL (SF-36)  (mental component of SF-36)	0.44	−4.05 to 4.93	0.85	0	0.59	Random inverse variance	2	109	Low
Cupping with active control versus control (add-on)
Pain (VAS)	−0.87	−1.14 to –0.61	<0.00001	19	0.29	Random inverse variance	5	534	Low
Disability (NDI)	3.61	−3.93 to 11.15	0.35	–	–	Random inverse variance	1	56	Low

MD, mean difference; NDI, Neck Disability Index; QoL, quality of life; SF-36, 36-Item Short Form Health Survey; VAS, visual analogue scale.