Cost-effectiveness of Prophylaxis Against Pneumocystis jiroveci Pneumonia in Patients with Crohn's Disease

Emerging evidence suggests that Pneumocystis jiroveci pneumonia is occurring more frequently in Crohn's disease patients on immunosuppressive medications, especially corticosteroids. Considering its excess mortality and the efficacy of chemoprophylaxis in reducing P. jiroveci pneumonia in acquired immunodeficiency syndrome, there is debate without consensus on the need for chemoprophylaxis in Crohn's disease patients on corticosteroids. We sought to address this debate using insights from simulation modeling. We used a Markov microsimulation model to simulate the natural history of Crohn's disease in 1 million virtual patients receiving appropriate care and who faced P. jiroveci pneumonia risks that varied with corticosteroid use. We examined several chemoprophylaxis strategies and compared their population-level economic and clinical impact using various indices including costs, quality-adjusted life expectancy, and incremental cost-effectiveness ratios. We also performed several nested probabilistic sensitivity analyses to estimate the health and economic impact of chemoprophylaxis in patients on triple immunosuppressive therapy. At the current PJP incidence, no PJP chemoprophylaxis was the preferred strategy from a population perspective. Considered chemoprophylactic strategies led to higher average costs and fewer P. jiroveci pneumonia cases. However, they also led to lower average quality-adjusted life expectancy and were thus dominated. Nevertheless, these alternative strategies became preferred with progressively higher risks of P. jiroveci pneumonia. Our results also suggest that PJP chemoprophylaxis may be cost-effective in patients on triple immunosuppressive therapy. Our findings support a case-by-case consideration of P. jiroveci pneumonia chemoprophylaxis in Crohn's disease patients receiving corticosteroids.