Mortality in cancer patients previously diagnosed with herpes zoster in the hospital setting: a nationwide cohort study

Background: Herpes zoster (HZ) is associated with underlying immunodeficiency and may thereby predict mortality of subsequent cancer. Methods: By using Danish nationwide medical databases, we identified all cancer patients with a prior hospital-based HZ diagnosis during 1982–2011 ( n =2754) and a matched cancer cohort without prior HZ ( n =26 243). We computed adjusted mortality rate ratios (aMRRs) associating prior HZ with mortality following cancer. Results: Prior HZ was associated with decreased mortality within the year after cancer diagnosis (aMRR 0.87; 95% confidence interval (CI): 0.81–0.93), but not thereafter (aMRR 1.07; 95% CI: 0.99–1.15). However, prior HZ predicted increased mortality throughout the entire follow-up among patients aged