Risk Factors for Late-Onset P jirovecii Pneumonia After Liver Transplantation

Risk factors for late-onset Pneumocystis jirovecii-associated pneumonia infection among liver transplant recipients include older age, cytomegalovirus (CMV) infection, hepatocellular carcinoma recurrence, and lymphocytopenia, according to findings published in the International Journal of Infectious Diseases.

Researchers conducted a retrospective case-control study between January 2009 and December 2019 to evaluate the clinical features associated with the occurrence of late-onset P jirovecii-associated pneumonia following liver transplantation. Eligible patients were liver transplant recipients who received routine postoperative prophylaxis. Patients who developed PCP infection were matched 1:4 against control patients, and the groups were compared to identify risk factors for late-onset PCP infection.

Among 742 liver transplant recipients included in the analysis, 27 developed late-onset PCP infection. All patients received basiliximab for induction immunosuppression. Maintenance suppression included calcineurin inhibitor, prednisolone, mycophenolate mofetil, or mammalian target of rapamycin inhibitor. Routine PCP prophylaxis was trimethoprim-sulfamethoxazole (400/80 mg) daily for 6 to 12 months following transplantation.

The median time from transplantation to pneumonia diagnosis was 25.6 (IQR, 12.9-53.9) months. The incidence of pneumonia was 6.36 per 1000 patient-years during a total of 4247 py of follow-up, with no breakthrough infections noted. 

The median age at transplantation was significantly higher among patients in the pneumonia vs control group (57 vs 54 years; P =.023).

The rate of CMV infection between transplantation and pneumonia onset was significantly higher among patients in the pneumonia vs control group (56.6% vs 28.7%; P =.012). This higher rate of CMV infection among patients who developed late-onset pneumonia was increased further when only data captured within the year prior to diagnosis were assessed. (40.7% vs 11.1%; P =.001).

In multivariate analyses, significant factors independently associated with the occurrence of late-onset PCP were as follows:

• Older age (≥65 years; odds ratio [OR], 10.564; 95% CI, 2.107-52.969; P =.004);
• Prior CMV diagnosis (≤1 year; OR, 5.566; 95% CI, 1.676-18.486; P =.005);
• Prior steroid pulse therapy (≤2 years; OR, 5.420; 95% CI, 1.717-17.106; P =.004);
• Prior HCC recurrence (≤3 years; OR, 16.900; 95% CI, 3.247-87.956; P =.001); and
• Prior lymphocytopenia (≤ 6 months; OR, 3.888; 95% CI, 1.230-12.88; P =.021).

Study limitations include the retrospective, case-control design and the inclusion of patients with probable rather than confirmed P jirovecii-associated pneumonia infection.

According to the researchers, “Targeted prophylaxis, considering the risk factors identified in this study, could help guide more effective prevention of this potentially lethal infection in LT [liver transplant] recipients.”