Estimated mean cumulative inpatient-days summed over 84 days in the modified intent-to-treat population. ^aInpatients at the time of study randomization. ^bHistory of Clostridium difficile infection recurrence within the previous 6 months. ^cDefined on the basis of a subject’s medical history or use of immunosuppressive therapy. ^dZar score ≥2 based on the following: (1) age >60 years (1 point); (2) body temperature >38.3°C (>100°F; 1 point); (3) albumin level <2.5 mg/dL (1 point); (4) peripheral white blood cell count >15 000 cells/mm³ within 48 hours (1 point); (5) endoscopic evidence of pseudomembranous colitis (2 points); and (6) treatment in an intensive care unit (2 points). Abbreviations: CDI, Clostridium difficile infection; CI, confidence interval.