DETERMINATION AND VALIDATION OF A PREDICTIVE MODEL FOR CLOSTRIDIUM-DIFFICILE DIARRHEA IN HOSPITALIZED ONCOLOGY PATIENTS

Background: Clostridium difficile colitis in the cancer patient receiv ing chemotherapy is a frequent cause of morbidity which may prolong ho spitalization. Techniques for identifying infection often delay the in itiation of therapy. Patients and methods: In this retrospective case- control analysis, we identified predictors for C, difficile-associated diarrhea in 29 patients hospitalized from 1988 to 1993 on a hematolog ic malignancy/bone marrow transplant unit (hospital A). We then valida ted our model with 58 C. difficile cases and 74 controls admitted to a n oncology unit from a different institution (hospital B). Results. We found that low intensity of chemotherapy (P < 0.001), lack of parente ral vancomycin use (P = 0.03) and hospitalization within the past two months (P = 0.05) were independently predictive of C. difficile coliti s by multivariate analysis. These variables were weighted for predicti ve capability using a receiver operator characteristic score; low inte nsity chemotherapy was assigned two points, lack of parenteral vancomy cin received one point and prior hospitalization one point (P < 0.001 by chi(2) for trend). The receiver operating characteristic (ROC) curv e areas were 0.78 for patients at hospital A and 0.70 at hospital B in dicating moderate drop off in discrimination. Compared to hospital A p atients, hospital B patients hospitalized between 1989 and 1994 were m ore often women (P = 0.04), received less systemic vancomycin (P = 0.0 1), were less frequently neutropenic (P < 0,05), and received less int ense chemotherapy regimens (P < 0,05). Despite these differences in de mographics in patients between these institutions, our predictive mode l was validated in hospital B patients (P = 0.02 by chi(2) for trend). Conclusions. The results of this study may help clinicians predict th e risk of C. difficile disease in the hospitalized immunocompromised o ncology patient and may help guide empiric therapy while awaiting resu lts of stool toxin assays.