Table 4.
Factors influencing length of stay
| Factors | LS mean (95% CI, days) | Adjusted increase in length of stay, as compared to referent group* | p value |
|---|---|---|---|
| MRSA/VRE Flag Status | |||
| MRSA/VRE Flag1 | 7.03 (6.83–7.24) | 1 day 18 hours | <.0001 |
| No flag for MRSA/VRE | 5.27 (5.15–5.38) | Ref | |
| Age | |||
| < 65 years | 6.00 (5.85–6.14) | Ref | <.0001 |
| ≥ 65 years | 6.17 (6.03–6.32) | 4 hours | |
| Severity of illness (acuity) on admission | |||
| Observation Unit | 2.04 (1.98–2.10) | Ref | <.0001 |
| General Care Unit | 7.22 (7.06–7.39) | 5 days 4 hours | |
| Step-Down Unit | 7.31 (7.08–7.55) | 5 days 7 hours | |
| Intensive Care Unit | 12.73 (12.35–13.11) | 10 days 17 hours | |
| Residence prior to admission, home | |||
| No | 6.31 (6.13–6.49) | 11 hours | <.0001 |
| Yes | 5.86 (5.73–6.00) | Ref | |
| Hospitalization within previous 30 days | |||
| No | 5.72 (5.59–5.85) | Ref | <.0001 |
| Yes | 6.47 (6.30–6.64) | 18 hours | |
| Clinical service | |||
| Surgical | 5.46 (5.33–5.60) | Ref | <.0001 |
| Medical | 6.77 (6.62–6.93) | 1 day 7 hours | |
| Discharge destination | |||
| Home | 3.77 (3.70–3.84) | Ref | <.0001 |
| Facility | 8.05 (7.87–8.23) | 4 days 7 hours | |
| Death | 7.43 (7.06–7.82) | 3 days 16 hours |
LS Mean: multivariate model based predicted mean, the average of predicted marginal mean over the classes of the simultaneously controlled covariates. The multivariate model also controlled for gender and admit day of week. Unadjusted observed means for MRSA/VRE flag status were 6.99 [95% CI 6.84–7.15] for patients with a flag and 4.13 [95% CI 4.10–4.16] for patients with no flag, which is an adjusted increase of 2 days and 21 hours for patients with a flag on admission (data not shown).
Length of increase in length of stay was rounded to the nearest integer
MRSA flag, VRE flag, and both MRSA and VRE flag were associated with an excess length of stay of 17 hours, 2 days and 3 hours, and 1 day and 14 hours, respectively, compared to patients with no flag.