Table 2.
Adjusted Association of Admission During Surge with 28-Day In-Hospital Mortality.a.
| Difference-in-Differences Models | ||||
|---|---|---|---|---|
| N (%) | OR (95% CI)a | p-valueb | ||
| Primary Analysis 1: IPW Model | 2052 | 1.30 (.47,3.58) | .61 | |
| Primary Analysis 2: Meta-Analysis | 3041 - 3,422c | 1.39 (1.34,1.43) | <.001 | |
| Simple Surge/Not Surge Models | ||||
| Not exposed, N (%) | Exposed, N (%) | OR (95% CI)d | p-valued | |
| Primary Surge Definition | ||||
| All Hospitals (N = 4342) | ||||
| Individual patient experienced surge | 3666 (84.4) | 676 (15.6) | 1.49 (1.10,2.02) | .009 |
| Admitted during hospital Surge | 3655 (84.2) | 687 (15.8) | 1.46 (1.08,1.96) | .014 |
| Only Surge Hospitals (N = 1265) | ||||
| Individual patient experienced surge | 589 (46.6) | 676 (53.4) | 1.23 (.88,1.73) | .23 |
| Admitted during hospital Surge | 578 (45.7) | 687 (54.3) | 1.21 (.87,1.69) | .26 |
| Alternative Surge Definitions | ||||
| All Hospitals (N = 4342); Individual patients experienced surge | ||||
| Model 1: surge as a patient-level continuous exposure (per 1% increase in ICU occupancy) | 3666 (84.4) | 676 (15.6) | 1.003 (1.001,1.005) | .008 |
| Model 2: surge as a patient-level categorical exposure | 3666 (84.4) | 676 (15.6) | ||
| <25% | Reference | |||
| 25 to 49% | 1.02 (.81,1.29) | .87 | ||
| 50 to 74% | 1.07 (.81,1.42) | .62 | ||
| 75 to 99% | 1.29 (.90,1.84) | .17 | ||
| 100 to 124% | 1.44 (.95,2.18) | .09 | ||
| 125 to 149% | 1.89 (1.01,3.53) | .046 | ||
| 150 to 174% | 2.46 (1.27,4.77) | .008 | ||
| 175 to 199% | 1.85 (.76,4.48) | .17 | ||
| 200 to 224% | .79 (.24,2.62) | .70 | ||
| 225 to 249% | 2.26 (.87,5.90) | .10 | ||
| 250 to 274% | 2.36 (1.12,4.97) | .024 | ||
| 275 to 299% | 2.90 (1.01,8.34) | .049 | ||
| 300 to 324% | 1.83 (.88,3.83) | .11 | ||
| 325 to 349% | 1.78 (.68,4.69) | .24 | ||
CI: confidence interval; IPW: inverse probability weighted; OR: odds-ratio.
All multivariable models included adjustment by the following covariables: age (grouped as <40, 40-49, 50-59, 60-69, 70-79, and 80 + ); male gender; race (categorized as White, Black, other, or unknown); body mass index (grouped as <25, 25-29, 30-34, 35-39, 40 + , and unknown); presence of diabetes mellitus; presence of hypertension; presence of coronary artery disease; presence of congestive heart failure; presence of chronic obstructive pulmonary disease; presence of cancer; current smoker; symptoms starting ≤3 days prior to intensive care unit admission; respiratory status at intensive care unit admission (not mechanically ventilated [MV]; MV with paO2/FiO2 ≥300; MV with paO2/FiO2 200-299; MV with paO2/FiO2 100-199; MV with paO2/FiO2 <100; and MV with unknown paO2/FiO2); use of vasopressors on intensive care unit day 1; renal sequential organ failure assessment (SOFA) score (grouped as 0/unknown, 1, 2, 3, or 4); coagulation SOFA score (grouped as 0/unknown, 1, 2, 3, or 4); liver SOFA score (grouped as 0, 1, 2, 3, 4, or unknown); and week of the study period for intensive care unit admission date. For the IPW model to create the propensity score, we also included adjustment for American Hospital Association geographic region (grouped as region 1 [Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont], 2 [New Jersey, New York, Pennsylvania], and 3-9 [all other states]).
for the interaction term of time period (pre-surge vs surge) and hospital surge status.
varies across 50 matched surge/non-surge hospital sets.
for the surge (vs not-surge) term in the model.