Infections in systemic autoimmune diseases

Infections are a major cause of morbidity and mortality in patients with systemic autoimmune diseases. The aim of the present study is to describe the frequency of infections in a historical cohort of the SAD polyclinic of the Maciel Hospital, according to the type of disease and treatment received.

An analytical, retrospective and observational study was conducted in 339 patients with SAD attended at the outpatient clinic in the period from January 1, 2012 to February 28, 2019. Infectious complications were analysed according to treatment and disease.

339 cases, median age 56, mostly female. Most cases presented SLE (30.1%) and RA (23.6%), followed by antiphospholipid syndrome (20.4%) and Sjögren's syndrome (12.1%). Hydroxychloroquine (66%), followed by corticosteroids (55.5%) were the most frequently used treatments. Thirteen point three percent received biological therapies: 46.9% of the cases presented some infectious complication, 95% were non-opportunistic. Respiratory infections were the most frequent (48.6%) followed by urinary infections (31.7%) and skin and soft tissue infections (17.6%). On comparing the infected and non-infected groups, significant differences were found in the following variables: methotrexate, mycophenolate, corticoids, biological therapies, combination of drugs, active disease, RA and cases with overlap. The use of hydroxychloroquine and sulfasalazine was associated with a lower risk of infection in patients with RA.

Infections are a frequent complication in patients with RA, due to the immune disturbances of the disease itself and prescribed treatments, mainly corticoids and biologicals. The importance of screening and infection prophylaxis before starting treatment is stressed.