Table 3.
Associations of baseline and index hospitalization characteristics with hospital readmissions after the index hospitalization.
| Variable | Univariable Models |
Multivariable Model 1* |
Multivariable Model 2* |
||||||
|---|---|---|---|---|---|---|---|---|---|
| HR | (95% CI) | p | HR | (95% CI) | p | HR | (95% CI) | p | |
| Male sex | 1.64 | (1.15, 2.33) | .006 | 1.50 | (1.04, 2.17) | .031 | 1.50 | (1.04, 2.18) | .032 |
| Age, per 10-year increase | 0.92 | (0.83, 1.01) | .093 | 0.88 | (0.78, 1.00) | .053 | 0.87 | (0.76, 0.99) | .041 |
| White race | 0.84 | (0.55, 1.30) | .44 | 0.88 | (0.57, 1.37) | .58 | 0.89 | (0.57, 1.40) | .62 |
| Insurance | .35 | .34 | .37 | ||||||
| Commercial | (ref) | (ref) | (ref) | ||||||
| Medicaid | 1.31 | (0.76, 2.24) | 0.90 | (0.50, 1.62) | 1.00 | (0.53, 1.88) | |||
| Medicare | 1.24 | (0.73, 2.13) | 1.12 | (0.62, 2.04) | 1.23 | (0.67, 2.26) | |||
| Other | 0.65 | (0.26, 1.66) | 0.52 | (0.20, 1.35) | 0.58 | (0.22, 1.50) | |||
| Index SI was a SSI | 0.76 | (0.52, 1.12) | .17 | 1.07 | (0.68, 1.67) | .78 | 0.93 | (0.59, 1.48) | .76 |
| Spine surgery during index hospitalization | 0.71 | (0.49, 1.02) | .067 | 0.73 | (0.50, 1.07) | .10 | 0.71 | (0.48, 1.05) | .089 |
| Medical comorbidities | |||||||||
| Cirrhosis | 1.74 | (0.91, 3.31) | .092 | 1.32 | (0.66, 2.63) | .43 | |||
| CKD | 1.19 | (0.76, 1.86) | .45 | 0.98 | (0.59, 1.65) | .95 | |||
| DM | 1.09 | (0.75, 1.59) | .64 | 1.02 | (0.67, 1.55) | .92 | |||
| Endocarditis | 1.44 | (0.88, 2.36) | .15 | 1.20 | (0.69, 2.08) | .51 | |||
| Chronic SCI/decubitus ulcer | 1.34 | (0.82, 2.20) | .25 | 1.03 | (0.58, 1.82) | .91 | |||
| HIV | 2.16 | (0.80, 5.85) | .13 | 1.33 | (0.46, 3.85) | .60 | |||
| Malnutrition | 1.40 | (0.95, 2.06) | .086 | 1.27 | (0.82, 1.96) | .29 | |||
| Non-IV drug use | 1.54 | (0.98, 2.43) | .063 | 1.43 | (0.86, 2.39) | .17 | |||
| IVDU | 1.08 | (0.75, 1.57) | .67 | 0.93 | (0.53, 1.62) | .79 | |||
| Number of comorbidities | .009 | .017 | |||||||
| 0 | (ref) | (ref) | |||||||
| 1 | 1.36 | (0.87, 2.14) | 1.19 | (0.72, 1.97) | |||||
| 2 | 1.85 | (1.13, 3.03) | 1.70 | (0.97, 3.00) | |||||
| 3+ | 2.33 | (1.36, 4.01) | 1.95 | (1.01, 3.79) | |||||
| LOS of index hospitalization, per 2-fold increase | 1.06 | (0.94, 1.20) | .37 | 1.00 | (0.87, 1.14) | .99 | 1.01 | (0.88, 1.15) | .94 |
HR, hazard ratio; CI, confidence interval; SI, spinal infection; SSI, surgical site infection; CKD, chronic kidney disease; DM, diabetes mellitus; SCI, spinal cord injury; HIV, human immunodeficiency virus; IV, intravenous; IVDU, intravenous drug user; LOS, length of stay.
⁎
383 patients who survived the index hospitalization and did not have any missing characteristics were included in the multivariable models.