Incidence and time trends of herpes zoster in rheumatoid arthritis: A population-based cohort study

Objective: To determine the incidence, time trends, risk factors, and severity of herpes zoster in a population-based cohort of patients with newly diagnosed rheumatoid arthritis (RA) compared to a group of individuals without RA from the same population. Methods: All residents of Olmsted County, Minnesota fulfilling for the first time the 1987 American College of Rheumatology criteria for RA between January 1, 1980 and December 31, 2007 and a cohort of similar residents without RA were assembled and followed by retrospective chart review until death, migration, or December 31, 2008. Results: There was no difference in the presence of herpes zoster prior to the RA incidence/index date between the cohorts (P = 0.85). During followup, 84 patients with RA (rate 12.1 cases per 1,000 person-years) and 44 subjects without RA (rate 5.4 cases per 1,000 person-years) developed herpes zoster. Patients with RA were more likely to develop herpes zoster than those without RA (hazard ratio [HR] 2.4 [95% confidence interval (95% CI) 1.7-3.5]). Herpes zoster occurred more frequently in patients diagnosed with RA more recently (HR 1.06 per year [95% CI 1.02-1.10]). Erosive disease, previous joint surgery, and use of hydroxychloroquine and corticosteroids were significantly associated with the development of herpes zoster in RA. There was no apparent association of herpes zoster with the use of methotrexate or biologic agents. Complications of herpes zoster occurred at a similar rate in both cohorts. Conclusion: The incidence of herpes zoster is increased in RA and has risen in recent years. There also has been an increasing incidence of herpes zoster in more recent years in the general population. RA disease severity is associated with the development of herpes zoster.