Clostridium difficile-associated diarrhoea in patients with human immunodeficiency virus infection: a case-control study.

OBJECTIVE: To evaluate the prevalence of, risk factors for, treatment and outcome of Clostridium difficile-associated diarrhoea (CDAD) in patients with human immunodeficiency virus (HIV) infection.

DESIGN: A prospective case-control study, conducted between January 1992 and April 1994.

SETTING: Department of Infectious Diseases in a large university hospital with HIV in- and out-patient units.

PATIENTS AND METHODS: The study included 124 patients grouped as follows: 31 HIV-infected patients with CDAD (group A); 31 HIV-seronegative patients with CDAD (group B) and 62 HIV-infected patients without CDAD (group C). The patients in group B and C were selected randomly during the study period.

RESULTS: The prevalence of CDAD in HIV-infected patients was 3.1% compared with 1.6% in HIV-seronegative patients (P = 0.02). On univariate analysis, the predisposing factors in group A were antibiotic use in the 4 weeks prior to the onset of CDAD (P = 0.03 versus group C), prolonged hospitalization (over 20 days; P = 0.04), low levels of circulating CD4+ cells (P = 0.03) and use of antacids (P = 0.04). The antibiotics significantly associated with CDAD were trimethoprim-sulfamethoxazole (P = 0.02 versus group C), third generation cephalosporins (P = 0.03) and clindamycin (P = 0.03). On multivariate analysis of the risk factors, the use of antibiotics was the sole independent risk factor for CDAD (P = 0.03). The clinical symptoms of CDAD were more severe in HIV-infected patients than in controls. Three patients in group A (9.7%) had one relapse and one patient (3.2%) experienced chronic diarrhoea. The outcome of CDAD was not influenced by the number of circulating polymorphonuclear cells and CD4+ cells. No difference in the survival curves of AIDS patients with or without CDAD, stratified according to age, sex and CD4+ cell count was observed.

CONCLUSIONS: Our data suggest that CDAD is more common in HIV-infected patients, particularly those receiving antibiotic therapy, than in HIV-seronegative patients. Since C. difficile can cause severe and recurrent or chronic infections in HIV-infected patients, CDAD must be always considered in the differential diagnosis of diarrhoea in patients with AIDS and AIDS-related conditions.