We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library, Issue 12, 2014), MEDLINE (January 2008 to December 2014), EMBASE (January 2008 to December 2014), ISI Web of Science (January 2008 to December 2014), World Health Organization Clinical Trials Registry, ClinicalTrials.gov, and reference lists of articles to identify additional studies. We applied no language restrictions.
SELECTION CRITERIA: DATA COLLECTION AND ANALYSIS: We included 59 trials involving 7667 participants. We rated two trials at low risk of bias in all domains (selection, attrition, reporting, blinding and other). We rated 25 trials at high risk in one or more risk-of-bias domains. Compared with
sham treatment,
PC6 acupoint stimulation significantly reduced the incidence of
nausea (RR 0.68, 95% CI 0.60 to 0.77; 40 trials, 4742 participants),
vomiting (RR 0.60, 95% CI 0.51 to 0.71; 45 trials, 5147 participants) and the need for rescue
antiemetics (RR 0.64, 95% CI 0.55 to 0.73; 39 trials, 4622 participants). As heterogeneity among trials was substantial and there were study limitations, we rated the quality of evidence as low. Using trial sequential analysis, the required information size and boundary for benefit were reached for both primary outcomes.
PC6 acupoint stimulation was compared with six different types of
antiemetic drugs (
metoclopramide,
cyclizine,
prochlorperazine,
droperidol.
ondansetron and
dexamethasone). There was no difference between
PC6 acupoint stimulation and
antiemetic drugs in the incidence of
nausea (RR 0.91, 95% CI 0.75 to 1.10; 14 trials, 1332 participants),
vomiting (RR 0.93, 95% CI 0.74 to 1.17; 19 trials, 1708 participants), or the need for rescue
antiemetics (RR 0.87, 95% CI 0.65 to 1.16; 9 trials, 895 participants). We rated the quality of evidence as moderate, due to the study limitations. Using trial sequential analyses, the futility boundary was crossed before the required information size was surpassed for both primary outcomes.Compared to
antiemetic drugs, the combination of
PC6 acupoint stimulation and
antiemetic therapy reduced the incidence of
vomiting (RR 0.56, 95% CI 0.35 to 0.91; 9 trials, 687 participants) but not
nausea (RR 0.79, 95% CI 0.55 to 1.13; 8 trials, 642 participants). We rated the quality of evidence as very low, due to substantial heterogeneity among trials, study limitations and imprecision. Using trial sequential analysis, none of the boundaries for benefit, harm or futility were crossed for
PONV. The need for rescue
antiemetic was lower in the combination
PC6 acupoint stimulation and
antiemetic group than the
antiemetic group (RR 0.61, 95% CI 0.44 to 0.86; 5 trials, 419 participants).The side effects associated with
PC6 acupoint stimulation were minor, transient and self-limiting (e.g. skin irritation, blistering, redness and
pain) in 14 trials. Publication bias was not apparent in the contour-enhanced funnel plots.
AUTHORS' CONCLUSIONS: There is low-quality evidence supporting the use of
PC6 acupoint stimulation over
sham. Compared to the last update in 2009, no further
sham comparison trials are needed. We found that there is moderate-quality evidence showing no difference between
PC6 acupoint stimulation and
antiemetic drugs to prevent
PONV. Further
PC6 acupoint stimulation versus
antiemetic trials are futile in showing a significant difference, which is a new finding in this update. There is inconclusive evidence supporting the use of a combined strategy of
PC6 acupoint stimulation and
antiemetic drug over
drug prophylaxis, and further high-quality trials are needed.