Summary of findings for the main comparison.

Acupuncture compared with sham for chronic neck pain
Patient or population: patients with chronic mechanical neck pain (pain for more than 90 days) Settings: varied, mostly at university or hospital clinics Intervention: acupuncture Comparison: sham
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	Number of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Sham	Acupuncture
Pain intensity (VAS) short term	Mean pain intensity ranged across sham groups from 3 points on a 0 to 10 scale to 47 points on a 0 to 100 scale	Mean pain intensity in intervention groups was 0.23 standard deviations lower (0.20 to 0.07 higher)	‐0.23 (‐0.20 to ‐0.07)	560 (8 studies)	⊕⊕⊕⊝ Moderate Limitations: ‐1 Inconsistency: 0 Indirectness: 0 Imprecision: 0 Other: 0	Statistical pooling was appropriate in this instance because of statistical homogeneity. Results of the meta‐analysis favoured acupuncture
Disability (NPQ) short term	Mean disability ranged across control groups from 24 points on a 0 to 100 scale to 26 points on a 0 to 100 scale	Mean disability in intervention groups was 0.38 standard deviations lower (0.62 to 0.15 higher)	‐0.38 (‐0.62 to ‐0.15)	290 (2 studies)	⊕⊕⊝⊝ Low Limitations: ‐1 Inconsistency: 0 Indirectness: 0 Imprecision: ‐1 Other: 0	Two small trials were in favour of acupuncture. On the basis of the GRADE scale, quality level of evidence was downgraded to low because only 1 of the 2 studies (50%) was at low risk with small sample size
Disability (NDI) short term	Mean disability ranged across control groups from 11 points on a 0 to 100 scale to 15 points on a 0 to 100 scale	Mean disability in intervention groups ranged from 3 points on a 0 to 10 scale to 11 points on a 0 to 100 scale	‐‐	173 (3 studies)	N/A	All 3 studies, 2 with low risk of bias, did not show a statistically significant result in favour of acupuncture
Quality of life (SF‐36) short term	Mean quality of life across control groups ranged from 86 points on a 0 to 100 scale to 86 points on a 0 to 100 scale	Mean quality of life in intervention groups ranged from 84 points on a 0 to 100 scale to 85 points on a 0 to 100 scale	‐‐	178 (1 study)	⊕⊕⊝⊝ Low Limitations: 0 Inconsistency: 0 Indirectness: ‐1 Imprecision: ‐1 Other: 0	One study with low risk of bias favoured acupuncture
*The basis for the assumed risk (e.g. median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI) CI: confidence interval; RR: risk ratio
Adverse effects were reported in 14 studies and included increased pain, bruising, fainting, worsening of symptoms, local swelling and dizziness. No life‐threatening adverse effects were noted by these studies. GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate Very low quality: We are very uncertain about the estimate