We agree with Dr. Nardone that clinicians use patterns of clinical and laboratory variables to solve problems. We have analyzed the manner in which the sequential addition of our identified predictors affected the diagnosis of C. difficile disease (Table 2). Although this information may be useful, the results are not statistically significant. For practical purposes, physicians will suspect C. difficile-associated enteric complications in any patient with otherwise unexplained diarrhea that occurs with exposure to antibiotics. Decisions about use of laboratory testing are optimally dictated by the effect of the test results on management and by the probability of a positive result. Cephalosporins are the major agents implicated in C. difficile-associated diarrhea in recent years [1, 2]. Usage rates indicate that clindamycin is probably the most commonly used agent, but not enough patients in our series were receiving clindamycin to allow us to verify this well-known association.
Published: Ann Intern Med. 1996;125(6):516.