## 3 Results
### The Association between Depression Symptoms, and CRP with the Length of Postoperative Hospital Stay  
Table 4 shows the results of the binary logistic regression analysis used to predict the impact of baseline depression on post-operative hospital LOS. Similar to the non-adjusted model of binary logistic regression (Model 1), the age and gender-adjusted model (Model 2) showed that patients in the mild to severe depression group (BDI-II \(>\) 13) had more than two times greater odds of a prolonged postoperative hospital LOS (\(>\)7 days) when compared to non-depressive symptom group. However, the only variable significantly predicting the prolonged hospital LOS in Model 2 was the patient's age (OR = 1.08, 95% CI = 1.04-1.13, \(p\) < 0.001). Model 3 of binary logistic regression included the following covariables significantly correlated ([PERSON]'s correlation analysis) with postoperative hospital LOS: current smoking (r = \(-\)0.213, \(p\) = 0.002), preoperative hemoglobin levels (r = \(-\)0.230, \(p\) = 0.001), the use of \(\beta\)-blockers (r = \(-\)0.163, \(p\) = 0.018), EuroSCORE-II (r = 0.318, \(p\) < 0.001), ventilation time (r = 0.165, \(p\) = 0.016) and postoperative atrial fibrillation (r = 0.242, \(p\) < 0.001). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Characteristics**} & \multicolumn{1}{c}{**Postoperative Hospital**} & \multicolumn{1}{c}{**Postoperative Hospital**} & \multicolumn{1}{c}{**\(p\)-Value**} \\  & **LOS \(\leq\) 7 Days; N = 88** & **LOS \(>\) 7 Days; N = 124** & \multicolumn{1}{c}{\(p\)-Value} \\ \hline Clinical factors & & & \\ Preoperative Hemoglobin (g/l) & 146.5 (138.0–154.0) & 139.5 (127.4–151.0) & \textless{}0.001 * \\ Anemia & 7 (8.0) & 26 (21.0) & 0.012 \\ Ejection Fraction (\%) & 55.0 (48.1–60.8) & 55.0 (45.0–60.0) & 0.325 \\ EuroSCORE-II & 0.9 (0.7–1.3) & 1.33 (0.9–2.7) & \textless{}0.001 * \\ Extubating time (ET) & 7.0 (5.0–9.0) & 8.0 (6.0–11.0) & 0.016 \\ On pump & 81 (92.0) & 112 (90.3) & 0.809 \\ Extracorporeal Circulation length & 78.0 (63.5–97.0) & 80.0 (63.0–100.0) & 0.763 \\ Number of grafts & 3.0 (2.0–3.0) & 3.0 (2.0–3.0) & 0.400 \\ Intensive care unit LOS, days & 2.0 (2.0–3.0) & 3.0 (2.0–3.0) & 0.022 \\ Postoperative atrial fibrillation & 8 (9.1) & 36 (29.0) & \textless{}0.001 * \\ Infection & 5 (5.7) & 8 (6.5) & \textgreater{}0.999 \\ Preoperative CRP, (mg/dL) & 1.8 (1.0–3.4) & 2.5 (1.21–4.9) & 0.113 \\ Early CRP Change score & 102.6 (83.5–139.9) & 109.3 (92.2–148.5) & 0.112 \\ Persistent CRP Change score & 61.0 (48.0–78.9) & 77.9 (58.2–100.8) & \textless{}0.001 * \\ Depression symptoms & & & \\ Total BDI-II scores & 7.0 (4.0–10.8) & 9.0 (6.0–12.0) & 0.014 \\ Binary BDI-II values & & & 0.137 \\ None (\(\leq\)13) & 81 (92.0) & 105 (84.7) & \\ Mild to Severe (\(>\)13) & 7 (8.0) & 19 (15.3) & \\ \hline \hline \end{tabular}  
* Data are presented as counts (n) and percentages (%) for categorical variables and as mean \(\pm\) standard deviation (SD) or median and interquartile range (IQR) for continuous variables. Statistical analysis was performed by Pearson \(\chi^{2}\) for categorical variables and by the Mann–Whitney U test for continuous variables, respectively. BMI, body mass index; CRP, high-sensitivity C-reactive protein; BDI-II, the Beck Depression Inventory; ICU, intensive care unit; MI, myocardial infarction.
* Significant \(p\) values (<Pc). Bonferroni correction for binary logistic regression analysis \(\text{Pc}=0.0016\) (0.05/n – number of model comparisons).  
\end{table} 
Table 3: \(Cont.\)Although the CABG patients in the mild to severe depression group showed a 1.21 times higher odds of prolonged hospital LOS when compared with the non-depressive symptoms group, that was not statistically significant (Table 4).