title: Community-acquired pneumonia in immunocompromised older patients: incidence, causative organisms and outcome.
abstract: The number of elderly patients in the community with immunosuppressive conditions has increased progressively over recent decades. We sought to determine the incidence, causative organisms and outcome of community-acquired pneumonia (CAP) occurring in immunocompromised older patients. We prospectively compared cases of CAP in immunocompromised and non-immunocompromised patients admitted to five public hospitals in three Spanish regions. Of 320 cases studied, 115 (36%) occurred in immunocompromised patients, including: solid or hematological malignancy (97), corticosteroids or other immunosuppressive drugs (44), solid organ or stem cell transplant (five), and other conditions (eight). The etiology was established in 44% of immunocompromised patients vs. 32% of non-immunocompromised patients (p 0.03). Streptococcus pneumoniae was the most common causative organism in both groups (29% vs. 21%; p 0.08), followed by Legionella pneumophila (3% vs. 6%; p 0.01). Gram-negative bacilli were more frequent among immunocompromised patients (5% vs. 0.5%; p <0.01), particularly Pseudomonas aeruginosa (3% vs. 0%; p 0.04). Nocardiosis was only observed in immunocompromised patients (two cases). Bacteremia occurred similarly in the two groups. No significant differences were found with respect to ICU admission (8%, in both groups) or the length of stay (12.5 vs. 10.4 days). The early (<48 h) (3.5 vs. 0.5%; p 0.04) and overall case-fatality rates (12% vs. 3%; p <0.01) were higher in immunocompromised patients. In conclusion, a substantial number of older patients hospitalized for CAP are immunocompromised. Although relatively uncommon, CAP due to gram-negative bacilli, including P. aeruginosa, is more frequent among these patients. CAP occurring in immunocompromised patients causes significant morbidity and mortality.
authors.affiliation: Department of Infectious Diseases, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain. dsoureg@sergas.es
authors.forename: D
authors.initials: D
authors.lastname: Sousa
authors.forename: I
authors.initials: I
authors.lastname: Justo
authors.forename: A
authors.initials: A
authors.lastname: Domínguez
authors.forename: A
authors.initials: A
authors.lastname: Manzur
authors.forename: C
authors.initials: C
authors.lastname: Izquierdo
authors.forename: L
authors.initials: L
authors.lastname: Ruiz
authors.forename: M
authors.initials: M
authors.lastname: Nebot
authors.forename: J-M
authors.initials: JM
authors.lastname: Bayas
authors.forename: J-M
authors.initials: JM
authors.lastname: Celorrio
authors.forename: W
authors.initials: W
authors.lastname: Varona
authors.forename: P
authors.initials: P
authors.lastname: Llinares
authors.forename: E
authors.initials: E
authors.lastname: Miguez
authors.forename: E
authors.initials: E
authors.lastname: Sánchez
authors.forename: J
authors.initials: J
authors.lastname: Carratalá
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000453:epidemiology / Q000209:etiology; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D015994:Incidence; D008297:Male; D018410:Pneumonia, Bacterial / Q000150:complications / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D013030:Spain / Q000453:epidemiology; D016019:Survival Analysis; D016896:Treatment Outcome