Characteristics of herpes zoster-associated hospitalizations in Madrid (SPAIN) before vaccine availability

Objectives: This study aimed to estimate the frequency of hospitalizations due to herpes zoster (HZ) and to describe their clinical characteristics by sex and age group. Methods: Descriptive population-based cross-sectional study of hospital admissions due to HZ from 2003 to 2013 among residents in the Autonomous Community of Madrid. Sex, age, comorbidities, length of stay and outcomes were collected and described. Crude and age-adjusted cumulative incidence rates, and stratified by sex and age, were estimated. Robust Poisson regression analysis was used to calculate the incidence rate ratios by age group. Results: 2039 hospitalizations were identified (51.0% in women). Complicated HZ caused 48.7% of them (50.9% in women). The hospitalization rate was 2.98/100,000 person-years and 7.19/1000 cases of HZ in primary care. Both rates were significantly higher in men, except in the extreme age groups. An immunosuppression-associated comorbidity was identified in 32.8% of the cases and was less common in patients >= 75 years of age. The median length of stay was 6 days, and in-hospital mortality was 1.4%. Conclusions: Hospitalization rates due to HZ were higher in men and increased with age. In two out of every three cases, a comorbidity that potentially caused immunosuppression could not be identified. These cases could benefit from vaccination. (C) 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.