TABLE 1.
Univariate Analysis of Demographic and Admission Characteristics of Patients Who Acquired Methicillin-Resistant Staphylococcus aureus during Hospitalization and Matched Control Patients
| Variable | Case patients (n = 451) | Control patients (n = 866) | OR (95% CI) | P |
|---|---|---|---|---|
| Age, years, mean ± SD | 60.2 ± 17.5 | 59.2 ± 16.4 | 1.00 (1.00–1.01) | .35 |
| Male sex | 250 (55.4) | 484 (55.9) | 0.95 (0.75–1.20) | .67 |
| Race | .98 | |||
| White | 330 (73.2) | 639 (73.8) | 1.00 | |
| Black | 42 (9.3) | 79 (9.1) | 1.02 (0.69–1.52) | |
| Other or unknown | 79 (17.5) | 148 (17.1) | 1.02 (0.75–1.41) | |
| Emergent or urgent admission | 401 (88.9) | 767 (88.6) | 1.06 (0.73–1.55) | .75 |
| Admission from long-term care facility | 41 (9.1) | 51 (5.9) | 1.52 (0.99–2.35) | .06 |
| Admitting service | .52 | |||
| Medical | 260 (57.6) | 520 (60.0) | 1.00 | |
| Surgical | 183 (40.6) | 329 (38.0) | 1.18 (0.88–1.58) | |
| Other | 8 (1.8) | 17 (2.0) | 0.92 (0.38–2.24) | |
| LOS, days, median (IQR) | 30 (17–50) | 32 (20–54) | 1.00 (1.00–1.00) | .51 |
| Prior to index culture | 12 (6–24) | 13 (8–24) | 1.00 (1.00–1.00) | .98 |
| In target unit | 21 (12–35) | 21 (12–34) | 1.00 (1.00–1.00) | .29 |
| Target unit stay prior to index culture | 447 (99.1) | 821 (94.8) | 6.27 (2.23–17.61) | <.001 |
| LOS in target unit prior to index culture, days, median (IQR) | 9 (5–18) | 10 (5–19) | 1.00 (1.00–1.00) | .65 |
| Other UPMC hospitalization during past 6 months | 100 (22.2) | 241 (27.8) | 0.73 (0.56–0.95) | .02 |
| Substance abuse or dependence | ||||
| Alcohol | 42 (9.3) | 95 (11.0) | 0.84 (0.57–1.23) | .37 |
| Drug | 23 (5.1) | 40 (4.6) | 1.16 (0.68–1.99) | .58 |
| Tobacco | 35 (7.8) | 72 (8.3) | 0.89 (0.58–1.38) | .61 |
| Primary diagnosisa | .08 | |||
| Cardiocirculatory disease | 51 (11.3) | 135 (15.6) | 1.00 | |
| Respiratory disease | 100 (22.2) | 146 (16.9) | 2.00 (1.26–3.17) | |
| Digestive tract disease | 48 (10.7) | 86 (9.9) | 1.59 (0.94–2.68) | |
| Cerebrovascular disease | 38 (8.4) | 71 (8.2) | 1.64 (0.87–3.06) | |
| Injury or trauma | 98 (21.8) | 186 (21.5) | 1.54 (0.97–2.45) | |
| Other diagnosisb | 115 (25.6) | 242 (27.9) | 1.38 (0.89–2.15) | |
| Age-adjusted Charlson comorbidity index, mean ± SD | 3.8 ± 2.9 | 4.0 ± 3.0 | 0.97 (0.93–1.01) | .13 |
| Total point value assigned for abnormal laboratory values,c median (IQR) | 5 (4–6) | 5 (4–6) | 0.95 (0.87–1.03) | .18 |
| Contact isolation for other target organism | 161 (35.7) | 339 (39.1) | 0.83 (0.64–1.07) | .14 |
| Discharge disposition | .15 | |||
| Alive | 286 (63.4) | 539 (62.2) | 1.00 | |
| Deceased | 112 (24.8) | 193 (22.3) | 1.10 (0.83–1.46) | |
| Unknown | 53 (11.8) | 134 (15.5) | 0.74 (0.52–1.06) | |
NOTE. Data are no. (%) of patients unless otherwise indicated. CI, confidence interval; IQR, interquartile range; LOS, length of stay; OR, odds ratio; SD, standard deviation; UPMC, University of Pittsburgh Medical Center.
Excludes 1 patient whose primary diagnosis was unknown.
Classified under hematology/oncology, infectious diseases, obstetrics/gynecology, rheumatology, dermatology, endocrinology, neurology, genitourinary, or psychiatry.
One point given for the presence of each of the following 9 laboratory values: white blood cell count of at least 15 or less than 3 ×109 cells/L, hematocrit level less than 30% or at least 46%, albumin level less than 3.5 g/dL, bilirubin level 2 mg/dL or more, creatinine level less than 0.6 or at least 1.4 mg/dL, bicarbonate level less than 22 or at least 32 meq/L, sodium level less than 130 or at least 150 mmol/L, potassium level less than 3.5 or at least 5.5 meq/L, and CD4+ count less than 200 cells/mm3. The most extreme laboratory value within 7 days of index culture was used and designated abnormal on the basis of hospital reference ranges and clinical cutoff values.