A systematic review and meta-analysis of risk factors for postherpetic neuralgia

Patients with herpes zoster can develop persistent pain after rash healing, a complication known as postherpetic neuralgia.By preventing zoster through vaccination, the risk of this common complication is reduced.We searched MEDLINE and Embase for studies assessing risk factors for postherpetic neuralgia, with a view to informing vaccination policy.Nineteen prospective studies were identified.Meta-analysis showed significant increases in the risk of postherpetic neuralgia with clinical features of acute zoster including prodromal pain (summary rate ratio 2.29, 95% confidence interval: 1.42-3.69),severe acute pain (2.23, 1.71-2.92),severe rash (2.63, 1.89-3.66),and ophthalmic involvement (2.51, 1.29-4.86).Older age was significantly associated with postherpetic neuralgia; for individual studies, relative risk estimates per 10-year increase ranged from 1.22 to 3.11.Evidence for differences by gender was conflicting, with considerable between-study heterogeneity.A proportion of studies reported an increased risk of postherpetic neuralgia with severe immunosuppression (studies, n 5 3/5) and diabetes mellitus (n 5 1/4).Systemic lupus erythematosus, recent trauma, and personality disorder symptoms were associated with postherpetic neuralgia in single studies.No evidence of higher postherpetic neuralgia risk was found with depression (n 5 4) or cancer (n 5 5).Our review confirms a number of clinical features of acute zoster are risk factors for postherpetic neuralgia.It has also identified a range of possible vaccine-targetable risk factors for postherpetic neuralgia; yet aside from age-associated risks, evidence regarding risk factors to inform zoster vaccination policy is currently limited.