Table 1.
Baseline covariates
| Variable | Unmatched Cohort | Matched Cohort | ||||
|---|---|---|---|---|---|---|
| Colistin, n=168 | Control, n=1222 | Standardized Differencea | Colistin, n=150 | Control, n=150 | Standardized Differencea | |
| Demographics | ||||||
| Age, yr, median (IQR) | 61 (48–70) | 64 (52–74) | 0.22 | 61 (48–70) | 59 (47–69) | 0.09 |
| BMI, mean (SD) | 27 (9.7) | 27 (9.6) | −0.01 | 27 (9.7) | 27 (8.8) | 0.07 |
| Men, n (%) | 103 (61) | 687 (56) | 0.1 | 91 (61) | 83 (55) | 0.11 |
| Race, n (%) | ||||||
| White | 97 (57) | 679 (56) | 0.04 | 88 (59) | 86 (57) | 0.03 |
| Black | 50 (30) | 406 (33) | −0.08 | 43 (29) | 42 (28) | 0.02 |
| Otherb | 21 (13) | 137 (11) | 0.04 | 19 (13) | 22 (15) | −0.06 |
| Admission | ||||||
| Admit type, n (%) | ||||||
| Medical | 63 (38) | 528 (43) | −0.12 | 57 (38) | 58 (39) | −0.01 |
| Surgical | 77 (46) | 539 (44) | 0.04 | 68 (45) | 72 (48) | −0.05 |
| Long-term acute care | 28 (16) | 155 (13) | 0.11 | 25 (16) | 20 (13) | 0.09 |
| Center, n (%) | ||||||
| HUP | 112 (67) | 700 (57) | 0.19 | 99 (66) | 102 (68) | −0.04 |
| PMC | 17 (10) | 220 (18) | 0.23 | 15 (10) | 16 (11) | −0.03 |
| PAH | 11 (7) | 147 (12) | −0.19 | 11 (7) | 12 (8) | −0.02 |
| RIT | 28 (16) | 155 (13) | 0.11 | 25 (16) | 20 (13) | 0.09 |
| Prior length of stay, median (IQR) | 10 (3–28) | 6 (1–17) | 0.34 | 11 (3–29) | 10 (3–24) | 0.07 |
| Prior ABX,c median (IQR) | 9 (5–15) | 4 (2–7) | 0.55 | 9 (5–16) | 9 (5–17) | 0.03 |
| ICU admission, n (%) | 93 (55) | 360 (29) | 0.54 | 81 (54) | 84 (56) | −0.04 |
| Mechanical ventilation, n (%) | 78 (46) | 368 (30) | 0.34 | 66 (44) | 60 (40) | 0.08 |
| Comorbidities, n (%) | ||||||
| Heart failure | 73 (43) | 484 (39) | 0.08 | 66 (44) | 63 (42) | 0.04 |
| Hypertension | 114 (68) | 854 (69) | −0.04 | 102 (68) | 102 (68) | 0 |
| Pulmonary disease | 83 (49) | 580 (47) | 0.04 | 76 (51) | 80 (53) | −0.05 |
| Liver disease | ||||||
| Mild | 28 (17) | 142 (12) | 0.15 | 22 (15) | 18 (12) | 0.08 |
| Severe | 10 (6) | 70 (6) | 0.01 | 10 (7) | 7 (5) | 0.09 |
| Diabetes | ||||||
| Uncomplicated | 35 (21) | 278 (23) | −0.05 | 32 (21) | 27 (18) | 0.08 |
| Complicated | 18 (11) | 111 (9) | 0.06 | 13 (9) | 13 (9) | 0 |
| CKD | 51 (30) | 379 (31) | −0.01 | 44 (29) | 45 (30) | −0.02 |
| Medications, n (%) | ||||||
| Aminoglycosides | 48 (29) | 95 (8) | 0.56 | 37 (25) | 31 (21) | 0.09 |
| Vancomycin | 75 (45) | 408 (33.4) | 0.23 | 68 (45) | 66 (44) | 0.03 |
| Inhaled antibioticsd | 13 (8) | 26 (2.1) | 0.26 | 12 (8) | 15 (10) | −0.07 |
| Intravenous acyclovir | 5 (3) | 10 (0.8) | 0.16 | 4 (3) | 3 (2) | 0.04 |
| ACEs/ARBs | 13 (8) | 133 (11) | −0.11 | 12 (8) | 12 (8) | 0 |
| NSAIDs | 5 (3) | 28 (2) | 0.04 | 4 (3) | 4 (3) | 0 |
| Loop diuretics | 48 (29) | 265 (22) | 0.16 | 43 (29) | 48 (32) | −0.07 |
| Calcineurin inhibitorse | 11 (7) | 74 (6) | 0.02 | 11 (7) | 10 (7) | 0.03 |
| Vasopressors | 27 (16) | 79 (6) | 0.31 | 21 (14) | 18 (12) | 0.06 |
| Iodinated contrast | 37 (22) | 221 (18) | 0.09 | 35 (23) | 39 (26) | −0.06 |
| Laboratory, median (IQR) | ||||||
| Hemoglobin, g/dl | 8.7 (7.9–9.8) | 9.4 (8.4–10.7) | −0.49 | 8.8 (7.9–9.8) | 8.7 (8.0–9.9) | 0 |
| WBC, ×108 cells per 1 L | 11.8 (7.4–18.0) | 10.5 (7.3–14.6) | 0.23 | 11.7 (7.2–18) | 11.4 (7.9–16.3) | 0.01 |
| Platelets, ×1011 cells per 1 L | 238 (111–351) | 250 (164–340) | −0.12 | 238 (113–361) | 248 (159–355) | −0.07 |
| Kidney function | ||||||
| Creatinine, mg/dl, median (IQR) | 0.7 (0.5–1.2) | 0.9 (0.6–1.3) | −0.23 | 0.7 (0.5–1.2) | 0.7 (0.5–1.1) | 0.03 |
| GFR, ml/min per 1.73 m2, median (IQR) | 86 (42–112) | 75 (46–104) | 0.23 | 86 (59–114) | 90 (58–123) | −0.06 |
| Prior AKI, n (%) | ||||||
| None | 118 (70) | 950 (78) | −0.17 | 106 (71) | 104 (69) | 0.03 |
| Yes: resolved | 32 (19) | 128 (10) | 0.24 | 28 (19) | 32 (21) | −0.07 |
| Yes: active | 18 (11) | 144 (12) | −0.03 | 16 (10) | 14 (9) | 0.04 |
| Microbiologic data | ||||||
| Organism, n (%) | ||||||
| Pseudomonas spp. | 69 (41) | 734 (60) | −0.38 | 68 (45) | 66 (44) | 0.03 |
| Klebsiella spp. | 72 (43) | 415 (34) | 0.18 | 60 (40) | 56 (37) | 0.06 |
| Acinetobacter spp. | 27 (16) | 73 (6) | 0.33 | 22 (15) | 28 (19) | −0.11 |
| Site, n (%) | ||||||
| Respiratory | 85 (51) | 460 (38) | 0.26 | 77 (51) | 76 (51) | 0.01 |
| Urine | 26 (15) | 485 (39) | −0.56 | 25 (17) | 23 (15) | 0.04 |
| Sterile sitef | 47 (28) | 173 (14) | 0.34 | 39 (26) | 41 (27) | −0.03 |
| Unknown | 10 (6) | 104 (9) | −0.09 | 9 (6) | 10 (7) | −0.03 |
| Time from culture to treatment, d, median (IQR) | 2.9 (1.0–4.6) | 1.1 (0.3–3.5) | 0.48 | 2.9 (0.9–4.7) | 2.9 (0.9–5.5) | −0.03 |
| Blood products,g n (%) | 44 (26) | 178 (15) | 0.29 | 37 (25) | 35 (23) | 0.03 |
Difference between groups refers to the standardized difference. IQR, interquartile range; BMI, body mass index; HUP, Hospital of the University of Pennsylvania; PMC, Presbyterian Medical Center; PAH, Pennsylvania Hospital; RIT, Penn Medicine at Rittenhouse; ABX, antibiotics; ICU, intensive care unit; ACE, angiotensin-converting enzyme; ARB, angiotensin receptor blocker; NSAID, nonsteroidal anti-inflammatory drug; WBC, white blood cell.
Standardized difference is a measure of covariate balance that is not effected by sample size. Values >0.10 are considered evidence of meaningful imbalance.
Other includes Asian, American Indian or Alaskan Native, Native Hawaiian, or other Pacific Islander.
Previous courses of any duration whether given consecutively or in combination.
Tobramycin or colistin.
Tacrolimus or cyclosporin.
Blood cultures (colistin, n=17; control, n=25), tissue cultures (colistin, n=11; control, n=8), biopsy cultures (colistin, n=5; control, n=4), or ascites fluid cultures (colistin, n=6; control, n=4).
Red cells, platelets, or fresh frozen plasma