Distribution characteristics of somatic hyperalgesic acupoints in patients with functional dyspepsia: A case-control study

Abstract

Objective

To investigate the distribution characteristics of somatic hyperalgesic acupoints in patients with functional dyspepsia (FD), at the same time, the receiver operating characteristic (ROC) curve was used with healthy subjects to evaluate the distribution characteristics of hyperalgesic acupoints, and summarize the objective rule of acupoint hyperalgesia in patients with FD, aiming to provide objective evidence for the acupoint sensitization theory and the scientific basis for optimizing acupoint selection strategies of acupuncture for FD.

Methods

A case-control study design was adopted with 40 patients with FD (FD group) and 38 healthy subjects (control group). The pressure pain threshold (PPT) and pain tolerance threshold (PTT) of acupoints on the abdomen, lumbar region, and lower limbs were measured by a pressure pain tester in both groups. The differences between the two groups were analyzed by statistical analysis, and the diagnostic efficacy of the sensitized acupoints was evaluated by ROC curve.

Results

(1) The PPT in the FD group was lower than that in the control group at Tianshu (ST25) (Right: 10.8 v.s. 12.6, P = 0.049) and Sanyinjiao (SP6) (Right: 16.3 v.s. 19.1, P = 0.023), respectively. (2) Compared with the control group, the PTT in the FD group was lower at Zhongwan (CV12) (22.8 v.s. 28.6, P = 0.002), Tianshu (ST25) (Left: 22.0 v.s. 28.2, P = 0.001. Right: 22.6 v.s. 27.3, P = 0.016), Zusanli (ST36) (Left: 21.3 v.s. 26.6, P = 0.007. Right: 51.8 v.s. 57.6, P = 0.030), Shangjuxu (ST37) (Left: 46.0 v.s. 52.7, P = 0.034. Right: 46.6 v.s. 58.4, P = 0.009), Xiajuxu (ST39) (Left: 44.9 v.s. 54.1, P = 0.021. Right: 44.8 v.s. 55.6, P = 0.006), Yinlingquan (SP9) (Left: 31.6 v.s. 44.1, P = 0.001. Right: 33.5 v.s. 42.8, P = 0.003), Sanyinjiao (SP6) (Left: 33.8 v.s. 43.7, P = 0.015. Right: 33.6 v.s. 41.5, P = 0.013), and Xiaochangshu (BL27) (Left: 41.9 v.s. 52.8, P = 0.007. Right: 46.5 v.s. 55.2, P = 0.038) separately. (3) The diagnostic efficacy of left Yinlingquan (SP9) was the best (AUC = 0.72, 95%CI: 0.61 to 0.83, P < 0.001), and the optimal cutoff value was < 44. Zhongwan (CV12) (AUC = 0.68) on the abdomen and left Tianshu (ST25) (AUC = 0.69) and right Xiajuxu (ST39) (AUC = 0.67) on the lower limbs, and the left Xiaochangshu (BL27) (AUC = 0.68) on the back all demonstrated the moderate diagnostic efficacy (AUC: 0.67 to 0.69). Furthermore, except for the PPT at the right Tianshu (ST25) (P = 0.17) and the PTT at the right Xiaochangshu (BL27) (P = 0.05), the results of ROC analysis for all the other acupoints showed statistical significance (P < 0.05), suggesting that the sensitization of these acupoints may be valuable potentially for the diagnosis of FD.

Conclusion

Patients with FD exhibit an objectively quantifiable hyperalgesic phenomenon, primarily characterized by a reduced PTT. The distribution of sensitized acupoints follows “horizontal distribution of acupoints” and “longitudinal division of meridians”, which may provide a scientific basis for acupoint selection in acupuncture for FD.