Late-onset pneumocystis pneumonia after kidney transplantation: A systematic review and meta-analysis of prevalence, risk factors, and outcomes

Late-onset Pneumocystis jirovecii pneumonia (PCP) is increasingly recognized in kidney transplant recipients (KTRs) despite widespread prophylaxis. However, its prevalence and risk factors remain unclear. We systematically searched electronic databases for studies published up to May 1, 2025, that reported prevalence or risk factors of late-onset PCP. Pooled prevalence, weighted mean differences (WMDs), and pooled odds ratios (ORs) were synthesized using a random-effects model. Of 1448 studies screened, 24 met inclusion criteria, comprising 57,662 KTRs, of whom 556 developed late-onset PCP. The pooled prevalence was 1.28 % (95 %CI 0.90–1.65). Lymphocyte counts were significantly lower in the infection group (WMD –408.34 cells/μL; 95 %CI –706.03 to −110.66). Risk was significantly increased with ABO-incompatible transplantation (OR 4.12; 95 %CI 1.04–16.30), rituximab induction (OR 4.77; 95 %CI, 1.50–15.21), corticosteroid (OR 2.56; 95 %CI 1.00–6.52) or mammalian target of rapamycin inhibitor (mTORi) maintenance (OR 2.37; 95 %CI 1.27–4.42), CMV infection (OR 5.21; 95 %CI 2.45–11.10), and rejection episodes (OR 2.93; 95 %CI 1.72–4.99), particularly when treated with plasma exchange, intravenous methylprednisolone, or rituximab. In contrast, cotrimoxazole prophylaxis reduced risk (OR 0.06; 95 %CI 0.01–0.60). Late-onset PCP was associated with graft loss (OR 6.11; 95 %CI 2.98–12.55) and mortality (OR 10.48; 95 %CI 1.92–57.16). Although uncommon, late-onset PCP in KTRs is strongly linked with ABO-incompatible transplantation, lack of cotrimoxazole prophylaxis, lymphopenia, CMV infection, corticosteroid and mTORi, and rejection. KTRs with these high-risk features, including those receiving mTORi and corticosteroid maintenance, should be considered for prolonged or life-long PCP prophylaxis. • The pooled prevalence of late-onset PCP infection in KTRs was 1.28 %. • Late-onset PCP was associated with increased risks of graft loss and mortality, indicating that this complication remains clinically relevant despite prophylaxis • Associated factors included ABO-incompatible transplantation, rituximab induction, maintenance therapy with corticosteroids or mTORi, lymphopenia, prior rejection and its treatment, and CMV infection. • Prolonged cotrimoxazole prophylaxis should be considered for high-risk kidney transplant recipients, particularly those with a prior history of CMV infection or receiving mTORi or corticosteroid therapy.