Clostridium difficile infection in the "oldest" old: clinical outcomes in patients aged 80 and older.

OBJECTIVES: Clostridium difficile infection (CDI) represents a cause of substantial morbidity, particularly for older adults. Although older age is a risk factor for CDI, few studies have specifically focused on clinical outcomes in older adults, particularly the "oldest" old.
DESIGN: Retrospective review.
SETTING: University of Michigan Health System. PARTICIPANTS: All patients aged 80 and older with a positive cytotoxin assay for C. difficile and a clinical course consistent with CDI during 2006. MEASUREMENTS: Clinical data were recorded, including comorbid conditions and treatment regimens, as well as outcomes, including treatment failure, infection relapse, and 90-day mortality.
RESULTS: Seventy patients aged 80 and older (mean 84.0+/-4.1) with CDI were identified. Metronidazole was given as initial therapy in 65 (92.8%); 18 of these 65 (27.7%) experienced treatment failure, requiring subsequent use of oral vancomycin. Serious adverse events included three episodes of toxic megacolon, two requiring colectomy. One death was directly attributable to CDI. All-cause mortality was 8.6% at 30 days and 17.1% at 90 days. Higher white blood cell (WBC) counts were independently associated with treatment failure (P=.02) and coronary artery disease with 90-day mortality (P=.02).
CONCLUSION: In older adults with CDI, treatment failure on metronidazole occurred frequently and was associated with higher WBC count. Larger prospective studies are needed to determine risk factors for treatment failure and relapse in order to develop better paradigms for CDI treatment in older adults. Initial therapy with vancomycin may be appropriate for elderly patients, especially those with elevated WBC counts.