Low Risk of Pneumonia From Pneumocystis jirovecii Infection in Patients With Inflammatory Bowel Disease Receiving Immune Suppression.

BACKGROUND & AIMS Use of immunosuppressants and inflammatory bowel disease (IBD) may increase the risk of pneumonia caused by Pneumocystis jirovecii (PJP). We assessed the risk of PJP in a population-based cohort of patients with IBD treated with corticosteroids, immune-suppressive medications, and biologics. METHODS We performed a population-based cohort study of residents of Olmsted County, Minnesota, diagnosed with Crohn's disease (n = 427) or ulcerative colitis (n = 510) from 1970 through 2011. Records of patients were reviewed to identify all episodes of immunosuppressive therapies and concomitant PJP prophylaxis through February 2016. We reviewed charts to identify cases of PJP, cross-referenced with the Rochester Epidemiology Project database (using diagnostic codes for PJP) and the Mayo Clinic and Olmsted Medical Center databases. The primary outcome was risk of PJP associated with the use of corticosteroids, immune-suppressive medications, and biologics by patients with IBD. RESULTS Our analysis included 937 patients and 6066 patient-years of follow-up evaluation (median, 14.8 y per patient). Medications used included corticosteroids (520 patients; 55.5%; 555.4 patient-years of exposure), immunosuppressants (304 patients; 32.4%; 1555.7 patient-years of exposure), and biologics (193 patients; 20.5%; 670 patient-years of exposure). Double therapy (corticosteroids and either immunosuppressants and biologics) was used by 236 patients (25.2%), with 173 patient-years of exposure. Triple therapy (corticosteroids, immunosuppressants, and biologics) was used by 70 patients (7.5%) with 18.9 patient-years of exposure. There were 3 cases of PJP, conferring a risk of 0.2 (95% CI, 0.01-1.0) to corticosteroids, 0.1 (95% CI, 0.02-0.5) cases per 100 patient-years of exposure to immunosuppressants, 0.3 (95% CI, 0.04-1.1) cases per 100 patient-years of exposure to biologics, 0.6 (95% CI, 0.01-3.2) cases per 100 patient-years of exposure to double therapy, and 0 (95% CI, 0.0-19.5) cases per 100 patient-years of exposure to triple therapy. Primary prophylaxis for PJP was prescribed to 37 patients, for a total of 24.9 patient-years of exposure. CONCLUSIONS In a population-based cohort of patients with IBD treated with corticosteroids, immunosuppressants, and biologics, there were only 3 cases of PJP, despite the uncommon use of PJP prophylaxis. Routine administration of PJP prophylaxis in these patients may not be warranted, although it should be considered for high-risk groups, such as patients receiving triple therapy.