Evolving risk factors and predisposing conditions of Pneumocystis pneumonia in non-HIV patients: A seven-year multicenter study

Objectives

As Pneumocystis pneumonia (PCP) increasingly develops in non-HIV patients without established immunocompromising factors, the study examined the evolving predisposing factors and at-risk medications.

Methods

This multicenter retrospective study included non-HIV PCP at seven clinical centers from 2016–2023. Patients were categorized by exposed medications and underlying predisposing diseases. Demographic characteristics, disease severity, treatment approaches, and outcomes were reported.

Results

470 non-HIV PCP were identified, and 420 probable cases were included for analysis. The proportion of PCP without established high-risk medications increased from 47% in 2016 to 61% by 2023. 209 (49.8%) received established high-risk medications, 106 (25.2%) with suspected at-risk medications, and 155 (36.9%) with no at-risk medications. Subjects with established high-risk medications were more likely to have hematological malignancies (50.2%, P<0.001). Those with suspected at-risk medications had higher rates of solid cancers (63.2%, P<0.001) and transplantation (24.5%, P<0.001). Overall mortality rates were 43.8% at 60-day, with comparable mortality across medication groups (log-rank P=0.08) but significant differences by disease category (log-rank P<0.001), with solid cancers exhibiting the worst outcome (58.0%).

Conclusions

The epidemiology of non-HIV PCP is evolving beyond traditional risk categories. Both emerging high-risk medications and predisposing comorbidities might require further investigation and addressed in prophylaxis guidelines.