Using meta-regression approach to explore the dose-response association between acupuncture sessions and acupuncture effects on chronic prostatitis/chronic pelvic pain syndrome.

BACKGROUND

The benefits of acupuncture on chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) have been well established according to previous studies. However, uncertainty exists regarding the dose-response relationship between acupuncture sessions and acupuncture effects for CP/CPPS. The objective of this study is to explore the association between the acupuncture sessions and its effects based on previously published data.

METHODS

A non-linear meta-regression approach with restricted cubic spline (RCS) was used to investigate the dose-response relationship between acupuncture sessions and its effects on the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI). PubMed, EMBASE, and Cochrane CENTRAL were searched up to May 20, 2018. Randomized controlled trials (RCTs) and case series studies (CSSs) reported the treatment sessions of acupuncture for CP/CPPS with at least two categories were eligible for inclusion.

RESULTS

Ten studies involving 329 participants were included, the results showed a J-shaped dose-response association between acupuncture sessions and NIH-CPSI score (range 0 to 43, with higher score indicating greater CP/CPPS symptoms). Overall, more acupuncture sessions received for CP/CPPS patients is associated with increased symptom relieving. After 6 acupuncture sessions, the NIH-CPSI decreased from 26.1 (95% CI: 25.3-27.0) to 18.5 (95% CI: 11.6-25.4), with a between-session difference of -7.6 (95% CI: -14.6 to -0.7). Considering the 95%CI, both robust-error meta-regression modeling [MD: -8.3 (95% CI: -10.4 to -6.3)] and sensitivity analysis without CSSs [MD: -8.1 (95% CI: -9.5 to -6.7)] demonstrated that 18 acupuncture sessions could reach a clinically meaningful improvement regarding NIH-CPSI score.

CONCLUSIONS

There appear to be dose-response relationship between acupuncture sessions and CP/CPPS outcome. Prolonged acupuncture sessions were associated with less NIH-CPSI score. According to current evidence, six acupuncture sessions might be the minimal required 'dose' to reach its clinical effects.