Incidence, Risk Factors, and Severity of Herpesvirus Infections in a Cohort of 121 Patients With Primary Dermatomyositis and Dermatomyositis Associated With a Malignant Neoplasm

Abstract

OBJECTIVE: Opportunistic infections have been reported in 15% to 21% of patients with inflammatory myositis. However, to our knowledge, no data are available regarding the incidence, risk factors, and severity of herpesvirus infections. DESIGN: Retrospective inception cohort study. SETTING: Two departments in tertiary teaching hospitals. Patients All patients diagnosed as having dermatomyositis (DM) according to the criteria of Bohan and Peter seen during a 13-year period. MAIN OUTCOME MEASURES: Cumulative incidence rates of herpesvirus infections using the Kaplan-Meier method and risk factors for herpesvirus infections during the first year of DM using Cox proportional hazards models. RESULTS: A total of 121 patients met the inclusion criteria (mean [SD] age, 52 [15] years; 85 were women [70%]). Seventy-six percent had primary dermatomyositis, and 24% had dermatomyositis associated with a malignant neoplasm. The mean (SD) duration of follow-up was 42 (33) months. During follow-up, 20 patients developed a total of 22 herpesvirus infections (16 developed herpes zoster infections). The incidence rates for herpesvirus and for herpes zoster infections were 49 and 33 episodes per 1000 patient-years, respectively. In multivariate analysis, a positive association was noted between the risk of herpesvirus infection and use of systemic corticosteroid therapy (hazard ratio [HR], 3.71 [95% confidence interval {CI}, 1.02-13.41]; P = .04), lymphocyte count lower than 6000/microL (HR, 3.55 [95% CI, 1.00-12.65]; P = .05), and creatine phosphokinase level higher than 300 U/L (HR, 4.81 [95% CI, 1.28-18.06]; P = .02). Dermatomyositis associated with a malignant neoplasm tended to be negatively associated with the risk of herpesvirus infection (HR, 0.16 [95% CI, 0.02-1.29]; P = .08). CONCLUSIONS: The risk of serious herpesvirus infections in patients with DM is high. Educational strategies and studies evaluating the risk-to-benefit and the cost-to-benefit balances of a prophylaxis with valacyclovir hydrochloride in selected patients with DM are warranted.