Herpes Zoster recurrence and its associated risk factors: A population-based study in primary care in Madrid region (central Spain)

Abstract

Background

Although Herpes Zoster (HZ) recurrence rates seem to be increasing, there are few studies exploring them in the general population. We aimed to investigate the HZ recurrence rates and associated risk factors in a large population-based study.

Methods

The Primary Care Electronic Health Records from the Community of Madrid were used to identify initial HZ episodes from January 1, 2016 to December 31, 2024. These cases were followed through December 31, 2024 to identify recurrences. Recurrence cumulative incidence rate was calculated. The association of multiple risk factors with recurrence was estimated by Cox regression, including multivariate analysis.

Results

There were 10,470 recurrences out of 290,170 initial episodes with a mean of 4.23 years of follow-up. The recurrence rate was 8.81 per 1000 person-years (3.6%). Risk factors significantly associated with recurrence were post herpetic neuralgia (PHN) [hazard ratio [HR] = 2.94; 95% confidence interval [CI], 2.69–3.36], other complications arising from HZ [HR = 1.71; 1.38–1.96], cardiovascular disease [HR = 1.20; 1.03–1.40], age over 60 years-old (1.20; 1.10–1.32) and sex (women) [HR = 1.08; 1.03–1.12].

Conclusion

Our results suggest that HZ recurrence is relatively frequent and multicausal. Complications of the first episode, specially PHN, play an important role in predicting recurrence.