Table 3.
90-day Incidence of C. difficile Infection for Antibiotic Courses
| Unadjusted 90-day Incidence (per 1000) | Unadjusted Relative Risk (95% CI) | Adjusted a 90-day Incidence (per 1000) | Adjusted a Relative Risk (95% CI) | |
|---|---|---|---|---|
| Initiation (7 d) | ||||
| No antibiotic | 0.81 | Reference | 0.57 | Reference |
| Any antibiotic | 1.90 | 2.34 (2.01, 2.53) | 1.02 | 1.80 (1.55, 1.97) |
| Clindamycin | 4.12 | 5.08 (3.55, 6.97) | 2.29 | 4.04 (2.74, 5.72) |
| Fluoroquinolones | ||||
| Moxifloxacin | 3.66 | 4.50 (3.77, 5.24) | 1.92 | 3.39 (2.83, 4.03) |
| Ciprofloxacin | 2.38 | 2.93 (2.49, 3.45) | 1.07 | 1.90 (1.57, 2.25) |
| Levofloxacin | 1.78 | 2.20 (1.66, 2.74) | 0.87 | 1.55 (1.11, 1.98) |
| Norfloxacin | 0.92 | 1.14 (.62, 1.57) | 0.61 | 1.09 (.65, 1.50) |
| Cephalosporins | ||||
| Cefixime | 4.74 | 5.83 (3.51, 9.66) | 2.41 | 4.26 (2.41, 7.42) |
| Cefuroxime | 2.66 | 3.28 (2.42, 4.29) | 1.39 | 2.46 (1.61, 3.45) |
| Cefprozil | 2.12 | 2.61 (1.49, 3.89) | 1.07 | 1.89 (1.13, 3.02) |
| Cephalexin | 1.96 | 2.41 (2.01, 2.80) | 1.05 | 1.85 (1.54, 2.15) |
| Macrolides | ||||
| Azithromycin | 2.23 | 2.75 (1.91, 3.69) | 1.22 | 2.15 (1.53, 2.95) |
| clarithromycin | 1.20 | 1.48 (.82, 2.06) | 0.74 | 1.32 (.73, 1.85) |
| Penicillins | ||||
| Amoxicillin-clavulanate | 2.89 | 3.55 (2.82, 4.34) | 1.37 | 2.43 (1.89, 3.08) |
| Cloxacillin | 1.90 | 2.35 (1.53, 3.28) | 1.08 | 1.90 (1.21, 2.79) |
| Amoxicillin | 1.39 | 1.71 (1.28, 2.11) | 0.87 | 1.53 (1.15, 1.92) |
| Sulfonamides and Trimethoprim | ||||
| Cotrimoxazole | 1.56 | 1.92 (1.52, 2.34) | 0.85 | 1.50 (1.19, 1.83) |
| Trimethoprim | 1.28 | 1.58 (.73, 3.48) | 0.73 | 1.29 (.73, 2.95) |
| Nitrofurantoin | 1.08 | 1.33 (.95, 1.70) | 0.57 | 1.00 (.72, 1.25) |
| Tetracycline | 0.86 | 1.06 (.65, 1.23) | 0.53 | 0.94 (.65, 1.11) |
| Duration | ||||
| 7 d | 1.90 | Reference | 1.02 | Reference |
| vs 5 d | 1.68 | 0.88 (.87, .90) | 0.93 | 0.91 (.90, .93) |
| vs 10 d | 2.19 | 1.15 (1.13, 1.17) | 1.14 | 1.12 (1.09, 1.14) |
| vs 14 d | 2.53 | 1.33 (1.27, 1.36) | 1.29 | 1.27 (1.21, 1.30) |
| Selection (7 d) | ||||
| Nitrofurantoin | 1.08 | Reference | 0.57 | Reference |
| vs cotrimoxazole | 1.56 | 1.45 (1.05, 2.10) | 0.85 | 1.50 (1.10, 2.21) |
| vs ciprofloxacin | 2.38 | 2.21 (1.65, 3.24) | 1.07 | 1.89 (1.45, 2.68) |
| Amoxicillin | 1.39 | Reference | 0.87 | Reference |
| vs levofloxacin | 1.78 | 1.28 (.91, 1.86) | 0.87 | 1.01 (.70, 1.45) |
| vs amoxicillin-clavulanate | 2.89 | 2.08 (1.53, 2.96) | 1.37 | 1.58 (1.15, 2.28) |
| vs moxifloxacin | 3.66 | 2.63 (2.03, 3.55) | 1.92 | 2.21 (1.67, 3.08) |
| Cloxacillin | 1.90 | Reference | 1.08 | Reference |
| vs cephalexin | 1.96 | 1.03 (.71, 1.59) | 1.05 | .97 (.65, 1.56) |
| vs clindamycin | 4.12 | 2.17 (1.35, 3.85) | 2.29 | 2.12 (1.32, 3.78) |
Abbreviation: CI, confidence interval.
aAdjusted for 14 resident-level covariates: age, sex, days of emergency department or acute care stay in the prior 31–90 days, Charlson comorbidity index, and history of C. difficile infection in the prior 2 years, acid suppressant use in the prior 90 days, functional status, and device use in the prior 30 days.