Pneumocystis Pneumonia in Patients with Autoimmune Diseases: A Retrospective Study Focused on Clinical Characteristics and Prognostic Factors Related to Death

BACKGROUND: With the increasing use of immunosuppressive agents, the number of opportunistic infections has risen in patients with autoimmune diseases. Pneumocystis pneumonia (PCP) is one of these opportunistic infections that have a high mortality rate. However, only a few studies have described PCP in these patients, and these studies are limited in scope. We conducted this retrospective study to describe the clinical characteristics and factors associated with outcomes of PCP in patients with autoimmune diseases. METHODS: A retrospective study was performed in laboratory diagnosed PCP patients with autoimmune diseases in an academic hospital over a 10-year period. Patients with human immunodeficiency virus (HIV) infection were not included. Clinical characteristics were collected and the factors related to death were analysed. RESULTS: A total of 69 patients with PCP during the study period were included. Common clinical features included fever (81%), cough (56%), and dyspnea (35%). Ground glass opacity (81%) and reticulation (52%) were the most common radiological findings. Concurrent pulmonary infections including bacterium, aspergillus and cytomegalovirus were found in 34% of the patients. The overall in-hospital mortality rate was 32%. High mortality was associated with lower PaO(2)/FiO(2) ratios and albumin levels. The lymphocyte count, CD4+ T cell count, previous usage of immunosuppressive agents, the duration and dose of glucocorticoids did not affect the outcome. CONCLUSIONS: The mortality rate in PCP patients with autoimmune diseases is high. Low PaO(2)/FiO(2) ratios and albumin levels are independent prognostic factors of mortality.