Epidemiology and risk factors associated with Pneumocystis jirovecii pneumonia in kidney transplant recipients after 6‐month trimethoprim‐sulfamethoxazole prophylaxis: A case‐control study

Background Pneumocystis jirovecii pneumonia (PCP) is an important cause of morbidity and mortality in kidney transplant recipients (KTRs), and prophylaxis with trimethoprim‐sulfamethoxazole (TMP‐SMX) is recommended. The aim of this study was to investigate incidence and risk factors for PCP in KTRs after 6‐month TMP‐SMX prophylaxis. Methods We conducted a case‐control study of patients with PCP who received 6‐month PCP prophylaxis with TMP‐SMX after kidney transplantation (KT). In cases of rejection, PCP prophylaxis was provided for six additional months after anti‐rejection therapy. Cytomegalovirus (CMV) infection was not considered an indication for PCP prophylaxis due to concerns of nephrotoxicity associated with TMP‐SMX. Results Among 3941 kidney or pancreas‐kidney transplant recipients, 67 (1.7%) developed PCP after discontinuing TMP‐SMX. A total of 47 patients with KT PCP and 94 controls were included. Duration of PCP prophylaxis was similar between cases and controls (median 6 months, P = .53). In multivariate analysis, rejection (OR 3.9; 95% CI 1.4‐11.1) and CMV infection (OR 2.4; 95% CI 1.0‐5.8) were independently associated with PCP development after TMP‐SMX. Rejection or CMV infection was observed in 70% of patients with PCP. Time to PCP development after rejection (median [IQR] 6 [5‐19] months) was slightly shorter than after CMV infection (median [IQR] 9 [5‐12] months; P = .18). Conclusion Post‐prophylaxis PCP occurred in