Incidence, risk factors, and severity of herpesvirus infections in a cohort of 121 patients with primary dermatomyositis and dermatomyositis associated with a malignant neoplasm.

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.