Risk and impact of herpes zoster among COPD patients: a population-based study, 2009-2014

Background: The objective of this study was to assess the incidence of Herpes Zoster (HZ) among patients with chronic obstructive pulmonary disease (COPD) and the impact of HZ on the underlying COPD. Methods: A retrospective cohort of all subjects older than 49 years was followed up between 2009 and 2014 using population and health databases of Valencia Region (Spain). HZ and COPD were identified using ICD-9 codes, differentiating COPD patients with inhaled corticosteroids prescriptions (COPD-ICS). The incidence of HZ was compared among 3 groups [non-COPD, COPD and COPD-ICS populations] and use of healthcare resource due to HZ for 6 months following HZ diagnosis through different statistical generalized linear models (GLM). We also compared resources consumption due to COPD before and after HZ. Results: The cohort consisted of 2,289,485 subjects, including 161,317 COPD patients of which 29,708 were COPD-ICS. HZ incidence rates were 11 (95% confidence interval [CI]: 10.7-11.4) and 13 (95% CI: 12.3-13.8) cases/1000 persons-year for COPD and COPD-ICS populations respectively. Incidence increased with age in all groups. The risk of HZ rose by 45 and 61% among COPD and COPD-ICS patients respectively compared to non-COPD (95% credible intervals [Crl]: 1.41-1.5 and 1.52-1.71 respectively). COPD patients consumed more resources due to their HZ than non-COPD. There was no statistically significant impact of the HZ on the resources consumed due to COPD during the 6 months post-HZ compared to the 6 months pre-HZ. Conclusions: The presence of COPD increases the risk, severity and impact of zoster episodes.