The prevalence of OI was 6.4% in our myositis cohort, higher than the rest of the inpatients of our hospital (1.7%; P < 0.01). High-dose glucocorticoids at disease onset and severe immunosuppression are the main factors implicated.

We conducted the current study to determine the prevalence, incidence density, and clinical significance of thyroid disease in a series of 109 patients diagnosed with idiopathic inflammatory myopathy. We analyzed 109 patients diagnosed with idiopathic inflammatory myopathy during a 20-year period (1986-2006). Routine determination of thyroid profile, including hormone levels and antithyroid antibodies (antithyroid peroxidase and antithyroglobulin antibody systematically, and antithyroid-stimulating hormone receptor antibody when appropriate) was carried out at onset and at least once again during the follow-up period. Human leukocyte antigen (HLA) study was performed by polymerase chain reaction sequence-specific oligonucleotide typing. Six patients (5.5%) developed thyroid disease (hypo- or hyperthyroidism), with an incidence density of 8.7 new cases per 1000 person-years; 4 of the 6 cases were of autoimmune origin (3.6%). Thyroid dysfunction, whether autoimmune or not, was clearly related with onset or relapse of disease activity. Neoplastic disease was detected in 3 of 4 (75%) patients with autoimmune thyroid disease, a significantly higher frequency than was observed in the remaining patients in the series (12 of 103, 11.7%; p < 0.05; RR: 22.8; 95% confidence interval, 2.2-236.6). HLA DRB1*04 was found in 4 of the 6 patients with thyroid disease and inflammatory myopathy. Thyroid disorders are clinically relevant in patients with inflammatory myopathies. An association was observed between autoimmune thyroid disease and cancer. Thyroid assessment is strongly recommended in patients with idiopathic inflammatory myopathy and clinical relapse.

BackgroundIdiopathic inflammatory myopathies, also known as myositis, are a heterogeneous group of acquired diseases of probable autoimmune origin, characterized by the presence of inflammatory muscle infiltrates.Infectious complications are not uncommon in myositis, and some predisposing factors, such as upper esophageal involvement, calcinosis cutis, ventilatory insufficiency due to diaphragm involvement, and immunosuppressive drug therapies, seem to be implicated.ObjectivesTo describe the prevalence, clinical characteristics, and risk factors for opportunistic infection (OI) in a cohort of patients with inflammatory myopathies, and compare mortality rates between those with and without OIs.MethodsIn total, 204 patients from our myositis cohort were reviewed to identify patients who had experienced an OI during the period 1986–2014. The patients' clinical characteristics, treatment received, and outcome were systematically recorded. Disease activity at the OI diagnosis and cumulative doses of immunosuppressive drugs were analyzed, as well as the specific pathogens involved and affected organs.ResultsThe prevalence of OI in the total cohort, was 6.4%: viruses, 44.4% (varicella-zoster virus, cytomegalovirus); bacteria, 22.2% (Salmonella sp., Mycobacterium tuberculosis, M. chelonae); fungi, 16.7% (Candida albicans, Pneumocystis jirovecii); and parasites, 16.7% (Toxoplamosis gondii, Leishmania spp.) were the pathogens detected. Lung and skin/soft tissues were the organs most commonly affected (27.8%). Overall, 55.6% of OIs developed during the first year after the myositis diagnosis and were significantly associated with administration of high-dose glucocorticoids (p=0.0148). Fever at onset of myositis (p=0.0317), biological therapy (p<0.001) and sequential administration of 4 or more immunosuppressive agents during myositis evolution (p=0.0032) were significantly associated with OI. All-cause mortality in the OI group was 3.69 deaths per 100 patients/year versus 3.40 in the remainder of the cohort (p=0.996).ConclusionsThe prevalence of OI was 6.4% in our myositis cohort. High-dose glucocorticoids at disease onset and severe immunosuppression are implicated in the development of these complications. Mortality did not differ from the remainder of the cohort.Disclosure of InterestNone declared