RISK-FACTORS FOR CLOSTRIDIUM-DIFFICILE-ASSOCIATED DIARRHEA IN HIV-INFECTED PATIENTS

Objective: To identify risk factors associated with a first episode of Clostridium difficile-associated diarrhoea (CDAD) in patients with HI V infection. Design: A case-control study. Setting: University teachin g hospital HIV inpatient unit. Patients and methods: Nineteen HIV-infe cted patients with CDAD, defined as diarrhoea with positive stool cult ure for Clostridium difficile (CD) and positive stool cytotoxin B assa y, were compared with 38 randomly selected controls (HIV-infected pati ents hospitalized on the ward on the day the matched case was diagnose d). CD isolates were phenotyped by electrophoretic protein patterns. R esults: The incidence of CDAD among HIV-infected patients was 4.1/100 of patient-admissions. On univariate analysis, cases were more likely to have used clindamycin [11 out of 19 compared with four out of 38; o dds ratio (OR) 19; 95% confidence interval (CI), 2-160; P=0.0007], and pyrimethamine (14 out of 19 compared with 13 out of 38; OR, 4.8; 95% CI, 1.4-16, P=0.02) in the month before diagnosis, and to have had cer ebral toxoplasmosis (12 out of 19 compared with 13 out of 38; OR, 2.8; 95% CI, 0.9-8.6; P=0.09). There was also a significant increase of th e risk of CDAD as duration of hospitalization in the ward increased (c hi2 for trend, P=0.007). Multivariate models associated two risk facto rs with CDAD: clindamycin use (OR, 42; 95% CI, 2-813; P=0.01), and pro longed hospitalization in the ward (OR, 3.6 per week in the ward; 95% CI, 1-13, P=0.048). Of 18 available CD isolates, 15 (83%) had identica l electrophoretic protein pattern. Conclusions: Clindamycin use and pr olonged hospitalization in the ward were the main risk factors associa ted with CDAD in this study. These observations, together with the occ urrence of one major phenotype of CD, suggest nosocomial transmission of CD in the ward.