Infection-related morbidity and mortality in patients with connective tissue diseases: a systematic review

Patients suffering from connective tissue diseases (CTDs) constitute an important subgroup of immunosuppressed patients at risk for developing serious infections. Prophylactic antibiotic administration may decrease infection-related morbidity and mortality burden in patients with CTD, though one needs first to evaluate the overall effect of infection on morbidity and mortality in such patients and the presence of adequate prognostic/risk factors for infection development. Studies focusing on infection-related morbidity and mortality in patients with CTD were reviewed. Data on disease type, therapeutic regimens used, including corticosteroid dose and method of administration as well as other immunosuppressive agents, and outcome were extracted to evaluate the existence of specific treatment patterns predisposing to infection as well as infectious disease-related morbidity and mortality in patients with CTD. Thirty-nine studies focusing on infection incidence and/or outcome in patients with CTD were identified and analyzed; the majority of the reviewed studies (20) included patients with systemic lupus erythematosus (SLE). The mortality attributed to infection was 5.2%, while the overall mortality was 20%. There were no adequate data on the specific effect patterns of corticosteroid and immunosuppressant treatment on infection risk. Pneumocystis jiroveci (carinii) pneumonia, evaluated independently, exhibited significant mortality in patients with Wegener's granulomatosis, polymyositis/dermatomyositis, and SLE. In conclusion, infectious diseases are a major cause of mortality in patients with CTD. However, treatment-related factors predisposing to serious infections have not been adequately outlined. In addition, there are no data regarding the effect of prophylactic practices involving antibiotic administration in morbidity and mortality.