Risk factor analysis ofHistoplasma capsulatumfungemia

The primary objective of the study was to investigate the risk factors for Histoplasma capsulatum fungemia. We conducted a retrospective case-control study among patients with histoplasmosis seen at Mayo Clinic in Rochester from 1 January 1991 through 31 December 2005. Blood cultures were prepared from specimens obtained from 111 patients with a diagnosis of histoplasmosis of which 55 had demonstrated H. capsulatum fungemia whereas the cultures of the remaining 56 patients were negative. The mean age of the patients was 56 years, of which 70% men and 95% were white. In univariate analysis, immunocompromised status (OR 2.9, P=0.008), peripheral leukocyte count (WBC)<3000 cells/mm(3) (OR 7.3, P<0.001), albumin<3.5 g/ dl (OR 3.1, P=0.018), and Charlson score of>4 (OR 2.9, P=0.022) were associated with H. capsulatum fungemia, but age>55 years was not (OR 1.4, P=0.38). In multivariable analysis, immunocompromised status (OR 2.4, P=0.043) and WBC<3000 cells/mm(3) (OR 6.5, P=0.001) remained significant factors associated with H. capsulatum fungemia. Immunocompromised status and WBC<3000 cells/ mm(3) are independent risk factors for the development of H. capsulatum fungemia.