PROGNOSTIC FACTORS OF SEVERE LEGIONELLA-PNEUMONIA REQUIRING ADMISSIONTO ICU

Despite the fact that the epidemiology of community-acquired pneumonia and nosocomial Legionella infection is well known, there are no speci fic reports dealing with severe cases of Legionella pneumophila pneumo nia admitted to intensive care units. We undertook a prospective study upon 84 patients with a reliable diagnosis of L. pneumophila pneumoni a that required ICU admission. The study assessed the prognostic facto rs, clinical, radiological and outcome variables of both nosocomial (n = 33) and community-acquired (n = 51) cases of L. pneumophila pneumon ia. The following variables were more common in nosocomial acquired as compared to community-acquired Legionella pneumonia: Chronic obstruct ive pulmonary disease (COPD) (64 versus 41%), cardiac disease (39 vers us 10%), chronic renal failure (21 versus 4%), alcoholism (54 versus 1 8%), septic shock (33 versus 16%), and unilateral chest X-ray involvem ent (61 versus 39%). The crude mortality rate in this study was 30% (2 5 of 84) with no differences when comparing mortality between nosocomi al (9, 27%) to community-acquired (16, 31%) types. The univariate anal ysis showed that cardiac disease, diabetes mellitus, creatinine greate r than or equal to 1.8 mg/dl, septic shock, chest X-ray extension, mec hanical ventilation, hyponatremia less than or equal to 136 mEq/L, PA( CO2)/FIO2 < 130, and blood urea levels greater than or equal to 30 mg/ dl were factors related to poor outcome. On the other hand, the follow ing two variables were related to better outcome: adequate treatment f or Legionella and pneumonia improvement. The logistic regression analy sis demonstrated that APACHE II score > 15 at admission (RR: 11.5; 95% CI 1.75 to 76.1; p = 0.025), and serum Na levels less than or equal t o 136 (RR: 21.3; 95% CI 1.11 to 408; p = 0.023), were the only indepen dent factors related to death. On the other hand, improving pneumonia is associated with better outcome in Legionnaires' disease than for pa tients not having improving pneumonia (RR: 0.019; 95% CI: 0.036 to 0.1 06; p < 0.0001). A better understanding of the prognostic factors in c ases of severe Legionella pneumonia will optimize our therapeutic appr oach in this disease and help to decrease both its mortality and morbi dity rates.