Corticosteroid Use and Risk of Herpes Zoster in a Population-Based Cohort

Objective: To examine the relationship between corticosteroid use and herpes zoster risk. Methods: With data from a large cohort of adults (the 45 and Up Study) recruited between 2006 and 2009 and linked to health data sets, the effect of corticosteroid use on zoster risk was analyzed by Cox proportional hazards models, adjusting for age, sex, and other characteristics. Results: During 602,152 person-years (median, 7.36 years) of follow-up, there were 20,048 new systemic corticosteroid users and 6294 incident herpes zoster events among 94,677 participants (zoster incidence, 11.0 per 1000 person-years). Compared with nonusers, the risk of zoster was 59% higher in those using systemic corticosteroids (adjusted hazard ratio [aHR], 1.59; 95% CI, 1.48 to 1.71) and greater with higher cumulative doses: aHR of 1.32 (95% CI, 1.17 to 1.48), 1.74 (95% CI, 1.55 to 1.95), and 1.80 (95% CI, 1.61 to 2.02) for use of less than 500 mg, 500 mg to less than 1000 mg, and 1000 mg or more prednisolone equivalents, respectively (P value for trend, <.001). Compared with nonusers, zoster risk increased significantly (aHR, 6.00; 95% CI, 4.85 to 7.42) in the month after a single prescription of systemic corticosteroids and returned to levels similar to those in nonusers by the third month after dispensing (aHR, 0.91; 95% CI, 0.49 to 1.69). Conclusion: Practitioners should be alert to the increased risk of zoster among patients taking systemic corticosteroids. Given the significant morbidity from zoster, particularly in older adults, these findings support judicious prescribing of corticosteroids, including using as low a dose and as short a course as possible.