Herpes zoster and postherpetic neuralgia: incidence and risk indicators using a general practice research database

BACKGROUND: Postherpetic neuralgia (PHN) is a frequent complication of herpes zoster (HZ). Treatment results of this severe and long-lasting pain syndrome are often disappointing. From the point of view of possible prevention and early treatment, it is important to identify HZ patients who have an increased risk of developing PHN. OBJECTIVES: Our goals were to determine the incidence of HZ and PHN in a primary care population and to identify risk indicators for the occurrence of PHN. METHODS: A search for HZ and PHN was conducted in a general practice research database, comprising 22 general practices and representing 49 000 people, over a 5-year period. Potential risk indicators were analysed using multivariate logistic regression. RESULTS: A total of 837 patients had been diagnosed with HZ incidence 3.4/1000 patients/year, 95% confidence interval (CI) 2.9-3.9. The risk of developing PHN 1 month after the start of the zoster rash was 6.5% (95% CI 4.9-8.3). This risk was 11.7% (95% CI 8.5-14.9) for patients aged > or =55 years. Independent risk indicators for the occurrence of PHN were age 55-74 years, adjusted odds ratio (OR) 4.2, 95% CI 1.8-9.7; >75 years, OR 10.7, 95% CI 4.6-25.1 and ophthalmic localization (OR 2.3, 95% CI 1.0-4.6). CONCLUSIONS: The risk of developing PHN increases with age. Preventive strategies should focus on patients with herpes zoster aged >55 years and with ophthalmic localization.