Table 3.
Multivariable Poisson Regression Analysis for the Length of Stay in Patients Who Underwent Partial Mastectomy for Breast Cancer without Exclusion of Outliers in the Postoperative Length of Stay.
| Surgery day of the week | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Monday | Tuesday | Wednesday | Thursday | |||||||||
| IRR* | 95%CI | P-value | IRR* | 95%CI | P-value | IRR* | 95%CI | P-value | IRR* | 95%CI | P-value | |
| Postoperative length of stay, days | 0.98 | (0.97 to 0.98) | <0.001 | 0.99 | (0.98 to 0.99) | <0.001 | 0.99 | (0.986 to 0.997) | 0.003 | 1.00 | (0.99 to 1.00) | 0.82 |
| Total length of stay, days | 1.10 | (1.09 to 1.10) | <0.001 | 1.02 | (1.02 to 1.03) | <0.001 | 1.00 | (0.99 to 1.00) | 0.29 | 1.00 | (0.99 to 1.00) | 0.64 |
Abbreviations: IRR, incidence rate ratio; CI, confidence interval.
*IRR is with reference to Friday surgery. Multivariable Poisson regression analysis with adjustment for background characteristics was conducted, using a generalized estimating equation to adjust for within-hospital clustering.