Prognostic Modeling and Clinical Evaluation of Adverse Factors in Postherpetic Neuralgia Treated With Botulinum Toxin Type A: A Randomized Controlled Trial.

[OBJECTIVES] This study aims to evaluate the efficacy of Botulinum toxin type A (BTX-A) in patients with postherpetic neuralgia (PHN) and to identify key prognostic factors associated with treatment response.

[METHODS] This prospective, randomized controlled trial enrolled patients with PHN from November 2023 to January 2024. Sixty patients were randomized into 2 groups: the BTX-A group (standard care plus BTX-A injections) and the control group (standard care alone). The primary outcome was the change in pain intensity, assessed using the Visual Analog Scale (VAS) before and after treatment. Secondary outcomes included changes in inflammatory factor levels, the use of analgesics, and the occurrence of adverse events.

[RESULTS] Compared with the control group, the BTX-A group showed significantly lower VAS scores and decreased inflammatory markers ( P <0.001). After 1 month, the frequency of analgesic use decreased in both groups ( P <0.001), but there was no difference between the groups. Multivariate logistic regression results showed that BTX-A was the only significant factor associated with pain reduction in PHN patients ( P <0.001). Cox regression prognostic model results identified Gabapentin frequency, IL-6, and C-reactive protein as significant predictors of BTX-A treatment response ( P <0.05). ROC analysis further showed that IL-6 was a strong predictor of BTX-A treatment response (AUC=0.804, P =0.034). Adverse events were rare and similar between groups.

[CONCLUSIONS] BTX-A may offer benefit in relieving pain and reducing inflammation in PHN patients compared with standard treatment, and IL-6 may be a strong predictor of efficacy.