EA was superior to pharmacological treatment when the treatment duration lasted for three menstrual cycles , evidence d by significantly higher curative rate .
No statistically significant differences between EA at SP6 and control groups were found regarding the VRS , RSS-COX1 , and RSS-COX2 .
The findings of our study suggested that EA can provide considerable immediate analgesia effect for PD .
Electroacupuncture ( EA ) is considered to be a promising alternative therapy to relieve the menstrual pain for primary dysmenorrhea ( PD ) , but the conclusion is controversial .
Here , we conducted a systematic review and meta- analysis specifically to evaluate the clinical efficacy from r and omized controlled trials ( RCTs ) on the use of EA in patients with PD .
Undue reliance on I2 in assessing heterogeneity may mislead
Background The heterogeneity statistic I2 , interpreted as the percentage of variability due to heterogeneity between studies rather than sampling error , depends on precision , that is , the size of the studies included . Methods Based on a real meta- analysis , we simulate artificially ' inflating ' the sample size under the r and om effects model . For a given inflation factor M = 1 , 2 , 3 , ... and for each trial i , we create a M-inflated trial by drawing a treatment effect estimate from the r and om effects model , using si2MathType@MTEF@5@5@+=feaagaart1ev2aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi = xH8viVGI8Gi = hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY = rqGqVepae9pg0db9vqaiVgFr0xfr = xfr = xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaGaem4Cam3aa0baaSqaaiabdMgaPbqaaiabikdaYaaaaaa@2FBE@/M as within-trial sampling variance . Results As precision increases , while estimates of the heterogeneity variance τ2 remain unchanged on average , estimates of I2 increase rapidly to nearly 100 % . A similar phenomenon is apparent in a sample of 157 meta-analyses . Conclusion When deciding whether or not to pool treatment estimates in a meta- analysis , the yard-stick should be the clinical relevance of any heterogeneity present . τ2 , rather than I2 , is the appropriate measure for this purpose
EA was superior to pharmacological treatment when the treatment duration lasted for three menstrual cycles , evidence d by significantly higher curative rate .
No statistically significant differences between EA at SP6 and control groups were found regarding the VRS , RSS-COX1 , and RSS-COX2 .
The findings of our study suggested that EA can provide considerable immediate analgesia effect for PD .
Electroacupuncture ( EA ) is considered to be a promising alternative therapy to relieve the menstrual pain for primary dysmenorrhea ( PD ) , but the conclusion is controversial .
Here , we conducted a systematic review and meta- analysis specifically to evaluate the clinical efficacy from r and omized controlled trials ( RCTs ) on the use of EA in patients with PD .