Evolving epidemiology of pneumocystis pneumonia: Findings from a longitudinal population-based study and a retrospective multi-center study in Germany

Abstract

Background: Pneumocystis pneumonia (PCP) is a life-threatening opportunistic infectious disease of immunocompromised patients. Its incidence has decreased worldwide in the past, but data concerning its recent epidemiology are lacking.

Methods: We retrospectively analyzed all German inpatient cases from January 1, 2014 to December 31, 2019, to describe the recent epidemiology, incidence, clinical course, mortality and underlying diseases of PCP. Simultaneously, we conducted a retrospective multi-center study at two German university hospitals, and analyzed PCP cases treated there to gain deeper insights on the basis of primary patient data.

Findings: The incidence of PCP significantly increased from 2·3 to 2·6 per 100,000 population from 2014 to 2019 (1,857 to 2,172 cases, +17·0%, p < 0·0001), as well as PCP-related deaths (516 to 615 cases, +19·2%, p = 0·011). The spectrum of underlying diseases changed: Risk groups with established chemoprophylaxis for PCP based on international guidelines (HIV, hematologic malignancies, and transplantation) showed a significant decrease in PCP cases and deaths. Others, especially those with solid malignancies, and autoimmune and pulmonary diseases showed a significant increase in case numbers and deaths. Data from the retrospective multi-center study added information regarding prophylaxis and diagnostics of PCP.

Interpretation: The incidence of PCP has reversed its trend, showing a significant increase in mortality on population level. Patients who were not previously considered in prophylactic measures are increasingly affected by PCP. This development deserves further investigation, and additional comprehensive guidelines for the use of chemoprophylaxis in new risk groups are needed.

Funding: Department of Nephrology and Hypertension, University Hospital Schleswig-Holstein, Kiel.

Keywords: AIDS, acquired immunodeficiency syndrome; DRG, diagnosis related groups; Epidemiology; GFSO, german federal statistical office; HIV; HIV, human immunodeficiency virus; ICD, international classification of diseases; ICU, intensive care unit; IQR, interquartile range; Immunosuppression; Non-HIV; Opportunistic infection; PCP, pneumocystis pneumonia; Pneumocystis pneumonia.

Figure 1

Epidemiological parameters of PCP in Germany 2014–2019. (a) Absolute numbers of PCP cases treated yearly in German hospitals (2014–2019), all (gray), male (blue) and female (red) patients; (b) Overall (gray) and sex-specific (red/blue) incidence of PCP in Germany (2014-2019); (c) Relative distribution of PCP patients by age in Germany in 2014 (black) and 2019 (gray).

Figure 2

Underlying diseases of PCP patients are changing. (a) Absolute numbers of PCP cases yearly in HIV- (purple) and non-HIV patients (orange) from 2014 to 2019 in Germany; (b) Absolute numbers of PCP cases with pre-specified groups of underlying diseases.

Figure 3

PCP-related deaths are increasing. (a) Absolute numbers of PCP-related in-hospital deaths yearly among all (gray), HIV- (purple) and non-HIV patients (orange) from 2014 to 2019 in Germany; (b) Absolute numbers of PCP-related in-hospital deaths among patients with pre-specified groups of underlying diseases; (c) Trends in the relative in-hospital mortality overall (gray), and HIV (purple) and non-HIV (orange) patients from 2014 to 2019; (d) Mean in-hospital mortality of all PCP cases with pre-specified groups of underlying diseases from 2014 to 2019.