AMSTERDAM – Intravenous tigecycline was significantly more effective than standard therapy at curing refractory Clostridium difficile infections, according to a case-control study presented at the European Society of Clinical Microbiology and Infectious Diseases annual congress.
Tigecycline effected a 76% clinical cure rate, compared with 53% for the combination regimen of intravenous metronidazole and oral vancomycin, Dr. Baltin Gergely Szabo reported. And despite the fact that those who took tigecycline had more clinically severe disease, no colectomies were required in that group, while two patients in the standard treatment arm did need the procedure.
Dr. Baltin Gergely Szabo
However, tigecycline didn’t significantly improve relapse rates or mortality, noted Dr. Szabo of the St. Stephan and St. Ladislaus Hospital-Clinic, Budapest, Hungary.
He presented the results of a matched case-control study of 90 patients with severe C. difficile infections, who were treated with either of the protocols. Patients who took tigecycline were more likely to have a recurrent infection (38% vs. 29%). Thus, they were also more likely to have previously been treated with metronidazole (38% vs. 24%) and vancomycin (24% vs. 7%). Prior tigecycline use was very rare in both groups (2% vs. 0%).
Those who took tigecycline were significantly younger as well (72 vs. 78 years), and more often men (56% vs. 30%). They were more likely to be hypertensive, have chronic obstructive pulmonary disease, have cancers, be immunosuppressed, and be chronic users of corticosteroids.
However, the Charlson comorbidity index was similar between the tigecycline and standard therapy groups (4.6 vs. 5). They were also matched for ATLAS scores (mean 7.8 in each group).
Significantly more patients taking tigecycline had acquired their infections during hospitalization (64% vs. 30%). They also had a longer duration of symptoms (17 vs. 10 days).
Imaging showed more severe disease in the tigecycline group with significantly more colonic distension, mural thickening, and ascites. Tigecycline patients had also undergone significantly more colonoscopies and blood cultures.
Tigecycline was given in the hospital for 7-10 days, with a 100-mg loading dose and subsequent 50-mg daily doses. The main duration of therapy was 10 days, but that varied widely, from 2 to 22 days. It was given only as first-line treatment to 15% of patients; the rest received tigecycline as an alternative treatment, often after the combination of metronidazole/vancomycin had failed. No adverse drug reactions occurred in the group.
Clinical cure was achieved in 76% of the tigecycline group and 53% of the standard protocol group – a significant difference. The drug was associated with a decreased rate of complicated disease course (29% vs. 53%) and significantly fewer colectomies (0 vs. 2).
Rates of toxic megacolon were equal (7% each group); ileus was more frequent in the tigecycline group (11% vs. 9%), but this difference was not statistically significant.
However, tigecycline had no impact on either in-hospital or 90-day relapse, or on in-hospital mortality (15 vs. 16 deaths). At 90 days, fewer patients taking the drug had died (17 vs. 21), but that difference was not statistically significant (P = 0.52).
A multivariate analysis identified several characteristics associated with a beneficial response to tigecycline:
• Male sex.
• Being immunosuppressed.
• Chronic steroid treatment.
• Malignancy.
• Longer duration of symptoms.
• Prior C. difficile infections.
• Nosocomial onset.
• Signs of severe infection on imaging.
Dr. Szabo said these characteristics can be used to create a profile of patients who might be good candidates for the drug.
He had no relevant financial declarations.
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