Poor functional status as a risk factor for severe Clostridium difficile infection in hospitalized older adults.

OBJECTIVES: To determine the role of impaired functional status as a risk factor for severe Clostridium difficile infection (CDI) in older adults.

DESIGN: Prospective cohort study.

SETTING: University of Michigan Health System, a 930-bed tertiary care hospital.

PARTICIPANTS: Hospitalized individuals with CDI aged 50 and older.

MEASUREMENTS: Demographic and clinical characteristics and a composite outcome, CDI severity score: fever (>38°C), acute organ dysfunction, white blood cell count greater than 15,000/μL, lack of response to therapy, intensive care unit admission, need for colectomy, or death from CDI. Preadmission functional status was assessed according to ability to perform activities of daily living (ADLs); participants were assigned to an ADL class (independent, some assistance, full assistance). Secondary outcomes included length of stay, 90-day mortality and readmission, and CDI recurrence.

RESULTS: Ninety hospitalized individuals with CDI were identified (mean age 66.6 ± 10.2); 58 (64.4%) had severe CDI as measured according to a positive severity score. At baseline, 25 (27.8%) required assistance with ADLs. On univariate analysis, ADL class of full assistance was associated with a positive severity score (odds ratio (OR) = 7, 95% confidence interval (CI) = 1.83-26.79, P = .004). In a multivariable model including age, ADL class, congestive heart failure, diabetes mellitus, depression, weighted Charlson-Deyo comorbidity score, immunosuppression, prior CDI, and proton pump inhibitor use, an ADL class of full assistance retained its association with a positive severity score (OR = 8.1, 95% CI = 1.24-52.95, P = .03). ADL class was not associated with secondary outcomes.

CONCLUSION: In this cohort of hospitalized older adults, impaired functional status was an independent risk factor for severe CDI.