Risk factors analysis for Pneumocystis jiroveci pneumonia (PCP) in patients with haematological malignancies and pneumonia

A retrospective matched case-control investigation was conducted to assess risk factors suggesting Pneumocystis jiroveci pneumonia (PCP) when pneumonia occurs in adult patients with haematological malignancies. Cases and controls included were HIV-negative, presented with pneumonia and had benefited from a bronchoalveolar lavage (BAL). The presence of Pneumocystis jiroveci cysts was systematically investigated by cytochemical staining and/or immunofluorescence. Cases were patients with Pneumocystis jiroveci cysts isolated on BAL fluid (n = 31, mean age 51 +/- 14 y; range 20-73 y). Controls were patients without Pneumocystis jiroveci cysts (n = 62, mean age 54 +/- 13 y; range 25-75 y) and were matched to case patients by age and y of pneumonia diagnosis. Statistical analysis indicated that the following factors were associated with PCP: vincristine (p = 0.009, odds ratio (OR) = 2.11, 95% confidence interval (CI): 1.19-3.72), a daily corticosteroid therapy for more than 1 month p = 0.05) during the past y, and a lymphocyte count less than 0.5 x 10(9)/l on the d of pneumonia diagnosis (p = 0.04). Clinicians should be aware, in order to evoke this diagnosis when pneumonia occurs in patients with these risk factors. The goal of this exploratory study was to identify risk factors that could eventually be further investigated by a larger prospective multicentre study.