Systematic Evaluation And Meta - Analysis Of Acupuncture And Moxibustion Treatment Of Postherpetic Neuralgia

BackgroundPostherpetic neuralgia (PHN) is a syndrome characterized by persistent pain following resolution of herpes zoster (HZ). The time interval used in the case definition of PHN varies in the literature from 1 to 6 months after rash resolution. The nature of neuropathic pain in PHN is variable; it may be described as continuous or paroxysmal, evoked or spontaneous, burning or lancinating, and be associated with a range of other sensory abnormalities in the skin such as paresthesia, dysesthesia and hyperesthesia. Although age, acute pain severity, rash severity, psychological distress, diabetes mellitus, nutritional deficiencies, and diminished cell-mediated immunity appear to be correlated with incidence of PHN, accurate predictors for PHN have not been defined. However, the most relevant risk factor is old age; the incidence of PHN increases sharply with advancing age, almost 10% in people with HZ over 40 years old, and 20% to 50% in people over 60 years. Due to chronic pain, individuals may experience depression, difficulty with concentrating, fatigue, insomnia, altered activities of daily life, and decrease of socialization.Treatments with established efficacy for the treatment of PHN include lidocaine, opioid analgesics, antiepileptic drugs (e.g., gabapentin and pregabalin) and tricyclic antidepressants (TCAs). However, treatment of PHN is difficult and a variety of treatments are offered without consensus about their effectiveness. What’s more, two systematic reviews concluded that there was insufficient evidence to recommend lidocaine or antidepressants as first-line treatment for PHN. Moreover, TCAs can cause adverse events (AEs) for PHN in older adults including sedation, xerostomia, confusion, dysrhythmia, weight gain and dizziness. Somnolence, dizziness, fatigue, ataxia and other AEs are also reported to be brought from antiepileptic drugs, lidocaine and opioid.Nowadays, PHN has been treated with various acupuncture methods in hospitals in China for many years. Two systematic reviews published in China with low-quality evidence for acupuncture treatment of PHN have implied that acupuncture may be beneficial to PHN. Some recently published randomized controlled trials (RCTs) have provided better evidence with which to assess the effectiveness of acupuncture for treating PHN. Thus, this current systematic review was conducted to assess the effectiveness and safety of acupuncture forPHN.ObjectivesThis systematic review assessed the effectiveness and safety of acupuncture for treating PHN.MethodsWe electronically searched the following databases:Cochrane Skin Group Trials Register, MEDLINE, EMBASE, CENTRAL, Chinese Biomedical Literature, Chinese Medical Current Content, and China National Knowledge Infrastructure, and manually searched other journals. Randomized controlled trials (RCTs) using acupuncture for PHN were included. Outcome measurements included pain intensity, global impression, quality of life, safety, and costs. Risk ratios (RR) were analyzed for dichotomous data, and mean difference (MD) or standardized mean difference for continuous data.ResultsEleven RCTs (n=668) were analyzed; all were Chinese. High or unclear risks of bias and heterogeneity were observed. Outcome assessment was at the end of treatment, with follow-up in only one trial. None of the RCTs used sham acupuncture or no treatment as control. Acupuncture was superior to drugs in reducing pain (MD-2.67,95% Cl-3.09 to-2.25, four RCTs) and improving global impression (RR 1.25,95% Cl 1.16 to 1.35, eight RCTs). Acupuncture plus drugs reduced pain more than drugs alone (MD-2.21,95% Cl-3.94 to-0.93, two RCTs) but with substantial heterogeneity (I2=87%, P=0.005). There was no statistical difference between acupuncture plus drugs and drugs alone in global impression (RR 1.29,95% Cl 0.90-1.84, two RCTs). Acupuncture was superior to drugs in improving four categories on the Medical Outcome Study 36-item short-form health survey (P=0.05 to 0.0001, one RCT). Adverse effects were described in six of 351 trials; none were severe. None of the RCTs mentioned cost.ConclusionThe evidence that acupuncture is superior to drugs (e.g., pregabalin, carbamazepine, indomethacin, vitamin B1, vitamin B12, cobalt amine, etc.) for treating PHN is encouraging but not conclusive, and the benefit of acupuncture as an adjunct to drugs is unclear. Acupuncture for PHN is safe.