Table 2.
Primary and Secondary Outcomes of Antibiotic Selection in Matched Cohort
| Outcomes | Preintervention (n = 62) |
Matched Postintervention (n = 62) |
All Postintervention (n = 102) |
Paired HRb (95% CI) |
P-W P Valuec |
|---|---|---|---|---|---|
| Primary outcome | |||||
| 30-d mortality | 5 (8.06) | 4 (6.45) | 4 (3.92) | 1.67 (.32–10.73) | .65 |
| Secondary outcomes | |||||
| CDI | 4 (6.45) | 1 (1.61) | 1 (0.98) | Inf (.66–Inf) | .07 |
| AKIa | 6 (9.68) | 1 (1.61) | 1 (1.61) | 6.00 (.73–276.0) | .05 |
| Death, CDI, or AKI at 30 d | 14 (22.58) | 6 (9.68) | 6 (5.88) | 4.67 (1.30–25.33) | .02 |
| Additional outcomesd | |||||
| Total duration of antibiotics, d, median (IQR) | 14 (9–25) | 13 (8–21) | 14 (9–21) | −0.50 (−5.05 to 4.50) | .85 |
| Hospital LOS, d, median (IQR) | 15.85 (9.9–25.5) | 15.75 (9.9–23.6) | 15.45 (10.2–21.0) | 0.75 (−4.15 to 5.55) | .74 |
| ICU LOS, d, median (IQR) | 3 (1–5) | 3 (1–5) | 2.5 (0–5) | 0.27 (−1.00 to 2.00) | .67 |
| Time to resolution of leukocytosis, d, median (IQR) | n = 50 3 (2–6) |
n = 57 3 (1–6) |
n = 93 3 (1–7) |
0.00 (−1.00 to 1.00) | .66 |
| Time to vasopressor discontinuation, d, median (IQR) | n = 23 4 (2–4) |
n = 24 2.5 (2–4) |
n = 31 3 (2–4) |
1.00 (−.45 to 2.00) | .14 |
| Admission culture with gram-positive bacteria demonstrating in vitro resistance to linezolid | 0 (0) | 0 (0) | 1 (0.98) | NA | NA |
| Admission culture with gram-positive bacteria demonstrating in vitro resistance to clindamycin | 5 (8.06) | 0 (0) | 0 (0) | Inf (.92–Inf) | .06 |
| Inpatient mortality | 7 (11.29) | 3 (4.84) | 10 (9.80) | 5.00 (.56–236) | .22 |
| 60-d mortality | 9 (14.52) | 4 (6.45) | 11 (10.78) | 3.50 (.67–34.5) | .18 |
| Thrombocytopenia | 1 (1.61) | 1 (1.61) | 2 (1.96) | Inf (.026–Inf) | 1.00 |
| Serotonin syndrome | 0 (0) | 0 (0) | 0 (0) | NA | NA |
| Peripheral neuropathy | 2 (3.23) | 0 (0) | 0 (0) | Inf (.188–Inf) | .50 |
| Lactic acidosis | 0 (0) | 0 (0) | 2 (1.96) | NA | NA |
| Initiation of RRT | 2 (3.23) | 1 (1.61) | 3 (2.94) | 2.00 (.10–118) | 1.00 |
| Discharge location | |||||
| Home | 29 (46.77) | 30 (48.39) | 55 (53.92) | 0.92 (.39–2.19) | 1.00 |
| SNF | 24 (38.71) | 23 (37.10) | 30 (29.41) | 1.08 (.47–2.49) | 1.00 |
| Rehabilitation/other | 0 (0) | 5 (8.06) | 6 (5.88) | 0.00 (.00–1.09) | .06 |
Values in bold are significant P values.
Data are presented as No. (%) unless otherwise indicated. HR marked “Inf” if postintervention rate is equal to zero. HR estimate would then have zero as a denominator and not have a defined value.
Abbreviations: AKI, acute kidney injury; CDI, Clostridioides difficile infection; CI, confidence interval; HR, hazard ratio; ICU, intensive care unit; Inf, infinite; LOS, length of stay; NA, not applicable; P-W, Prentice-Wilcoxon; RRT, renal replacement therapy; SNF, skilled nursing facility.
AKI defined by the RIFLE (risk, injury, failure, loss, end-stage renal disease) criteria by comparing serum creatinine on admission to serum creatinine values on any subsequent day of admission. Patients who initiated RRT at any time during hospitalization were also considered “yes” for AKI.
HR for paired data estimated using the paired Cox proportional hazard model. Resulting CIs and P values use this same statistic.
P value calculated from the Prentice-Wilcoxon statistic for paired censored data. This test, while similar to the paired proportional hazards model, is influenced by frequency and time to event of the outcomes within each group.
Data in the “Additional outcomes” section are reported as paired difference (95% CI). Difference in continuous outcomes evaluated using paired differences within the matched pairs and tested using the Wilcoxon signed-rank statistic with P value reported from result of the test. Reported point estimate and confidence based on the Hodges-Lehmann estimator, which is compatible with the Wilcoxon signed-rank statistic. Binary outcomes analyzed with McNemar test, with its reported point estimate and 95% CI along with its P value.