Appendix Table 1.
Patient characteristics and covariate balance in matched sample
| Unmatched | Matched | |||
|---|---|---|---|---|
| Infected | Uninfected | Infected | Uninfected | |
| Urinary tract infection sample | N=13,153 | N=315,925 | N=8,058 | N=8,049 |
| % female sex | 62.5 | 55.1 | 60.1 | 67.4 |
| Mean (SD) age in years | 65.9 (17.4) | 57.5 (19.9) | 65.0 (17.6) | 67.3 (16.2) |
| % with ICU stay | 46.4 | 16.0 | 47.4 | 45.4 |
| Mean (SD) days in ICU | 6.4 (17.1) | 0.8 (3.5) | 7.0 (18.9) | 5.3 (12.0) |
| % with urinary catheter | 78.6 | 47.0 | 77.3 | 78.4 |
| Mean (SD) days with urinary catheter | 13.9 (21.6) | 2.4 (5.3) | 13.3 (21.4) | 11.6 (19.0) |
| % with central venous catheter | 41.9 | 14.8 | 42.2 | 39.8 |
| Mean (SD) days with central venous catheter | 9.0 (23.2) | 1.1 (4.8) | 9.1 (24.4) | 6.9 (15.4) |
| % underwent operating room procedure ≥30 minutes | 35.0 | 21.1 | 37.5 | 37.2 |
| Mean (SD) Charlson Comorbidity Index | 2.9 (2.6) | 1.9 (2.4) | 2.7 (2.6) | 2.8 (2.7) |
| Mean (SD) 3M Severity of Illness | 3.2 (0.8) | 2.3 (0.9) | 3.1 (0.8) | 3.0 (1.0) |
| Bloodstream infection sample | N=5,837 | N=332,824 | N=3,611 | N=3,603 |
| % female sex | 42.2 | 56.5 | 42.5 | 40.6 |
| Mean (SD) age in years | 61.5 (17.2) | 58.1 (20.0) | 61.6 (17.3) | 62.8 (16.4) |
| % with ICU stay | 59.7 | 15.6 | 59.3 | 54.4 |
| Mean (SD) days in ICU | 10.6 (21.1) | 0.7 (3.3) | 11.2 (24.6) | 9.8 (17.3) |
| % with urinary catheter | 72.0 | 47.4 | 73.2 | 76.7 |
| Mean (SD) days with urinary catheter | 17.2 (26.3) | 2.5 (5.4) | 18.0 (27.1) | 17.1 (21.4) |
| % with central venous catheter | 61.1 | 14.2 | 59.1 | 59.3 |
| Mean (SD) days with central venous catheter | 16.7 (30.3) | 1.0 (4.4) | 16.0 (29.9) | 14.7 (25.1) |
| % underwent operating room procedure ≥30 minutes | 29.5 | 21.6 | 33.3 | 36.7 |
| Mean (SD) Charlson Comorbidity Index | 3.2 (2.7) | 1.9 (2.4) | 3.1 (2.7) | 3.4 (2.8) |
| Mean (SD) 3M Severity of Illness | 3.5 (0.7) | 2.3 (0.9) | 3.5 (0.7) | 3.4 (0.8) |
| Surgical site infection sample | N=1,776 | N=108,558 | N=1,296 | N=1,293 |
| % female sex | 43.5 | 58.4 | 41.0 | 43.3 |
| Mean (SD) age in years | 59.6 | 56.6 (19.0) | 59.8 (17.1) | 59.6 (17.7) |
| % with ICU stay | 51.8 | 23.9 | 55.3 | 50.0 |
| Mean (SD) days in ICU | 9.3 (20.8) | 1.2 (5.1) | 10.2 (20.8) | 7.8 (16.4) |
| % with urinary catheter | 82.2 | 7.6 | 85.0 | 83.2 |
| Mean (SD) days with urinary catheter | 18.2 (26.2) | 4.3 (7.2) | 19.0 (25.8) | 15.7 (21.2) |
| % with central venous catheter | 57.7 | 25.0 | 59.5 | 49.9 |
| Mean (SD) days with central venous catheter | 15.0 (27.3) | 1.8 (7.3) | 16.0 (30.0) | 11.5 (20.4) |
| % underwent operating room procedure ≥30 minutes | 67.1 | 51.2 | 71.4 | 68.1 |
| Mean (SD) Charlson Comorbidity Index | 2.6 (2.6) | 1.7 (2.2) | 2.6 (2.6) | 2.7 (2.5) |
| Mean (SD) 3M Severity of Illness | 3.3 (0.8) | 2.2 (1.0) | 3.3 (0.8) | 3.2 (0.9) |
| Pneumonia sample | N=3,700 | N=320,244 | N=2,014 | N=2,010 |
| % female sex | 39.6 | 56.8 | 44.8 | 41.8 |
| Mean (SD) age in years | 64.5 (17.1) | 57.7 (20.0) | 64.2 (17.0) | 67.0 (16.3) |
| % with ICU stay | 79.7 | 15.4 | 43.0 | 83.5 |
| Mean (SD) days in ICU | 17.9 (25.6) | 0.7 (3.2) | 16.4 (22.6) | 12.0 (13.7) |
| % with urinary catheter | 82.3 | 47.8 | 40.0 | 86.5 |
| Mean (SD) days with urinary catheter | 23.7 (28.4) | 2.4 (5.4) | 22.6 (27.6) | 20.2 (21.6) |
| % with central venous catheter | 71.5 | 14.4 | 68.0 | 75.3 |
| Mean (SD) days with central venous catheter | 20.3 (29.3) | 1.0 (4.8) | 18.6 (27.1) | 14.1 (20.2) |
| % underwent operating room procedure ≥30 minutes | 40.7 | 21.9 | 42.0 | 41.7 |
| Mean (SD) Charlson Comorbidity Index | 3.0 (2.5) | 1.9 (2.3) | 3.0 (2.5) | 2.8 (2.5) |
| Mean (SD) 3M Severity of Illness | 3.8 (0.4) | 2.3 (0.9) | 3.8 (0.5) | 3.7 (0.6) |
Propensity score model included sex, age in five year intervals; year and month of admission; hospital; organism; infection site; prior hospitalization; diabetes; chronic dermatitis; trauma; wounds; burns; prior stay in a skilled nursing facility; renal failure; history of substance abuse; having ≥1 hospital roommate; Agency for Healthcare Research and Quality Clinical Classifications Software (CCS) categories; use of and number of days of use of chemotherapeutic, immunosuppressive, and anti-inflammatory medications; mechanical ventilation; urinary, central venous, or cardiac catheterization; catheter angiography; vascular stenting; dialysis; surgical procedure; general anesthesia; intubation; intensive care unit stay; and day of hospital stay on which the infection occurred.