## 3 Results
### Patient Demographic and Clinical Data
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Characteristics**} & **BDI-II \(\leq\) 13** & **BDI-II \(>\) 13** & \multirow{2}{*}{_p_**-Value**} \\  & **N = 186** & **N = 26** & \\ \hline Clinical factors & & & \\ Preoperative Hemoglobin (g/l) & 142.0 (134.0–152.0) & 136.5 (120.3–153.5) & 0.044 \\ Anemia & 25 (13.4) & 8 (30.8) & 0.038 \\ Ejection Fraction (\%) & 55.0 (45.0–60.0) & 50.0 (44.5–56.3) & 0.066 \\ EuroSCORE-II & 0.99 (0.68–1.71) & 2.63 (1.9–5.22) & \textless{0.001} * \\ Extubating time (ET) & 7.0 (5.0–10.0) & 9.0 (6.75–12.25) & 0.029 \\ On pump & 170 (91.4) & 23 (88.5) & 0.711 \\ Extacorporeal Circulation length & 80.0 (63.0–99.0) & 76.0 (60.0–92.0) & 0.478 \\ Number of grafts & 3.0 (2.0–3.0) & 3.0 (2.0–3.0) & 0.749 \\ Postoperative hospital length of stay (days) & 8.0 (7.0–9.0) & 10.00 (7.00–11.25) & 0.025 \\ Binary postoperative hospital length of stay & & & 0.137 \\ values & & & \\ \(\leq\)7 days & 81 (43.5) & 7 (26.9) & \\ \(>\)7 days & 105 (56.5) & 19 (73.1) & \\ Intensive care unit length of stay (days) & 3.0 (2.0–3.0) & 2.0 (2.0–3.0) & 0.175 \\ Postoperative atrial fibrillation & 36 (19.4) & 8 (30.8) & 0.198 \\ Infection & 12 (6.5) & 1 (3.8) & \textgreater{0.999} \\ Baseline CRP (mg/dL) & 2.1 (1.0–4.0) & 4.8 (1.6–8.3) & 0.007 \\ Early CRP Change score & 103.7 (86.1–145.1) & 119.9 (96.0–150.8) & 0.212 \\ Persistent CRP Change score & 68.1 (51.8–91.1) & 74.2 (52.1–88.4) & 0.834 \\ \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 2: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Characteristics**} & **Postoperative Hospital** & **Postoperative Hospital** & \multirow{2}{*}{_p_**-Value**} \\  & **LOS \(\leq\) 7 Days; N = 88** & **LOS \textgreater{} 7 Days; N = 124** & \\ \hline Age (years) & 58.9 \(\pm\) 7.8 & 63.5 \(\pm\) 7.5 & \textless{0.001} * \\ Gender (male) & 76 (86.4) & 95 (76.6) & 0.081 \\ Smoking & 21 (24.4) & 11 (8.9) & 0.003 \\ BMI (kg/m\({}^{2}\)) & 28.1 (25.3–30.3) & 28.4 (26.0–31.1) & 0.460 \\ Baseline medications & & & \\ Beta-blockers & 81 (92.0) & 98 (80.3) & 0.029 \\ Acetylsalicylic acid & 82 (93.2) & 105 (84.7) & 0.083 \\ AC inhibitors & 58 (65.9) & 74 (59.7) & 0.390 \\ Station medications & 80 (90.9) & 111 (91.0) & \textgreater{0.999} \\ Antidepressants & 1 (1.1) & 1 (0.8) & \textgreater{0.999} \\ Medical history & & & \\ Hypertension & 76 (86.4) & 109 (87.9) & 0.835 \\ Diabetes & 23 (26.1) & 54 (43.5) & 0.013 \\ Hyperlipidemia & 70 (79.5) & 89 (71.8) & 0.260 \\ Family history of cardiovascular diseases & 54 (62.1) & 78 (63.4) & 0.885 \\ Preoperative MI & 42 (47.7) & 68 (54.8) & 0.331 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Association between a postoperative hospital stay and patients’ demographic and clinical data. Regarding the association of the patient's depressive symptoms with the postoperative length of stay, no significant association between postoperative length of stay and binary BDI-II depression scores was detected (Table 3). Only the continuous BDI-II scores at baseline were associated (\(p\) = 0.014) with a prolonged hospital LOS. However, that association did not remain significant after the Bonferroni correction was applied. Interestingly, although only two participants in our patient cohort were under antidepressant therapy, both of them were in the non-depressive symptom group (BDI-II \(\leq\) 13) (Table 2).