3.3. The association of BDI-II and PHQ-9 depression scores with patient demographic and clinical data
As can be seen in Table 3, depressive symptoms determined by a BDI-II score of > 13 was associated with current smoking status (P = 0.026), lower preoperative hemoglobin (P = 0.044), and higher EuroSCORE-II values (P < 0.001); and with longer ventilation time (P = 0.029) and overall hospital LOS (P = 0.025). However, no statistically significant association was found in respect to gender and BDI-II scores and the patient’s postoperative LOS ( ≤ 7 days vs. > 7 days) or LOS in the ICU (Table 3). Patients with depressive symptoms determined by a BDI-II score of > 13 exhibited higher preoperative (baseline) CRP values (P = 0.007) and higher day 1 postoperative CRP values (P = 0.046). The depressed patient group also had lower ejection fraction values (measured in percent), but the results were not statistically significant (P = 0.066). No statistically significant association was found between either BDI-II scores and “early”, “persistent” and “overall” postoperative changes in CRP values or between BDI-II scores and patient comorbidities or medications used (Table 3). Interestingly, while only two participants in our patient cohort were using antidepressants, all of them were in the non-depressed patient group.
In contrast, depressive symptoms determined by the PRIME-MD/PHQ-9 test (PRIME-MD > 4) were associated only with gender (P = 0.024) and lower preoperative hemoglobin levels (P = 0.036) (Table 3). EuroSCORE-II values were also higher in patients with a PRIME-MD score of > 4; however, this was not statistically significant (P = 0.075). Interestingly, in the PRIME-MD analysis of the patient’s depression status, participants using antidepressants were equally distributed between the depressed and non-depressed patient groups. No statistically significant difference was found regarding preoperative CRP values or in the “early”, “persistent” and “overall” postoperative CRP response between the PRIME-MD ≤ 4 and PRIME-MD > 4 patient groups (Table 3).
In addition, Spearman’s correlation analysis revealed a significant positive correlation between gender and continuous BDI-II (rs = 0.174, P = 0.011) and PRIME-MD (rs = 0.183, P = 0.008) as well as binary BDI-II (rs = 0.145, P = 0.035) and PRIME-MD values (rs = 0.0.159, P = 0. 020). A positive correlation was also detected with smoking (continuous BDI-II: rs = 0.171, P = 0.013; binary BDI-II: rs = 0.162, P = 0.018), diabetes (continuous BDI-II: rs = 0.204, P = 0.003; binary BDI-II: rs = 0.136, P = 0.048; continuous PRIME-MD: rs = 0.139, P = 0.043) and EuroSCORE-II values (continuous BDI-II: rs = 0.328, P > 0.001; binary BDI-II: rs = 0.335, P > 0.001; continuous PRIME-MD: rs = 0.146, P = 0.033) while preoperative hemoglobin levels showed a negative correlation with depression scores (continuous BDI-II: rs = -0.143, P = 0.037; binary BDI-II: rs = -0.139, P = 0.044; continuous PRIME-MD: rs = -0.138, P = 0.044; binary PRIME-MD: rs = -0.145, P = 0.035).
Table 3
The association between depression symptom scores (BDI-II and PRIME-MD) and patients demographic and clinical data
Characteristics
|
BDI-II ≤13
N=186
|
BDI-II > 13
N=26
|
P-values
|
PRIME-MD ≤ 4
N=117
|
PRIME-MD > 4
N=95
|
P-values
|
Age (years); Mean ± SD
|
61.57±7.857
|
61.88±8.696
|
0.850
|
62.40±7.43
|
60.63±8.47
|
0.107
|
Gender; n (%)
|
|
|
0.059
|
|
|
0.024*
|
male
|
154 (82.8)
|
17 (65.4)
|
|
101 (86.3)
|
70 (73.7)
|
|
female
|
32 (17.2)
|
9 (34.6)
|
|
16 (13.7)
|
25 (26.3)
|
|
Smoking; n (%)
|
|
|
0.026*
|
|
|
0.087
|
Yes
|
24 (13.0)
|
8 (30.8)
|
|
13 (11.3)
|
19 (20.0)
|
|
No
|
160 (87.0)
|
18 (69.2)
|
|
102 (88.7)
|
76 (80.0)
|
|
BMI (kg/m2); Median [IQR]
|
28.2 (25.7-30.7)
|
28.4 (25.6-31.8)
|
0.672
|
28.1 (25.6- 30.6)
|
28.4 (26.1- 31.1)
|
0.564
|
Body Surface Area (BSA), m2; Mean ± SD
|
2.02±0.20
|
1.96±0.21
|
0.126
|
2.03±0.19
|
1.99±0.22
|
0.236
|
Medications; n (%)
|
|
|
|
|
|
|
Beta blockers
|
160 (86.5)
|
19 (76.0)
|
0.224
|
99 (85.3)
|
80 (85.1)
|
1.000
|
Acetylsalicylic acid
|
165 (88.7)
|
22 (84.6)
|
0.521
|
101 (86.3)
|
86 (90.5)
|
0.397
|
AC inhibitors
|
114 (61.3)
|
18 (69.2)
|
0.520
|
73 (62.4)
|
59 (62.1)
|
1.000
|
Statin medications
|
169 (91.4)
|
22 (88.0)
|
0.480
|
106 (91.4)
|
85 (90.5)
|
1.000
|
Antidepressants
|
2 (1.1)
|
0 (0.0)
|
1.000
|
1 (0.9)
|
1 (1.1)
|
1.000
|
Co-morbidities; n (%)
|
|
|
|
|
|
|
Hypertension
|
163 (87.6)
|
22 (84.6)
|
0.752
|
104 (88.9)
|
81 (85.3)
|
0.535
|
Diabetes
|
63 (33.9)
|
14 (53.8)
|
0.053
|
36 (30.8)
|
41 (43.2)
|
0.085
|
DMI
|
26 (14.0)
|
7 (26.9)
|
0.143
|
18 (15.4)
|
15 (15.8)
|
1.000
|
Hyperlipidemia
|
141 (75.8)
|
18 (69.2)
|
0.630
|
85 (72.6)
|
74 (77.9)
|
0.427
|
Familiar history of cardiac diseases
|
118 (64.1)
|
14 (53.8)
|
0.386
|
69 (59.5)
|
63 (67.0)
|
0.315
|
Preoperative myocardial infarction (MI)
|
93 (50.0)
|
17 (65.4)
|
0.150
|
60 (51.3)
|
50 (52.6)
|
0.890
|
Clinical factors
|
|
|
|
|
|
|
Preoperative leukocyte number; Median [IQR]
|
7.2 (6.2-8.6)
|
7.7 (6.5-9.4)
|
0.310
|
7.4 (6.3- 8.6)
|
7.2 (6.2- 9.2)
|
0.993
|
Preoperative Platelate number; Median [IQR]
|
212.0 (178.0-250.8)
|
230.0 (167.8-277.5)
|
0.412
|
212.0 (179.0-249.0)
|
220.0 (174.0-266.0)
|
0.267
|
preoperative GUK; Median [IQR]
|
6.1 (5.2-7.3)
|
6.5 (5.3-8.8)
|
0.359
|
6.1 (5.3-7.6)
|
6.3 (5.2-7.3)
|
0.779
|
Preoperative Hemoglobin (Hb); Median [IQR]
|
142.0 (134.0-152.0)
|
136.5 (120.3-153.5)
|
0.044*
|
145.0 (136.0-152.0)
|
140.0 (128.0-153.0)
|
0.036*
|
Ejection Fraction (%);Median [IQR]
|
55.0 (45.0-60.0)
|
50.0 (44.5-56.3)
|
0.066
|
55.0 (45.0-60.0)
|
55.0 (47.5-60.0)
|
0.611
|
EuroSCORE-II; Median [IQR]
|
0.99 (0.68-1.71)
|
2.63 (1.9-5.22)
|
<0.001*
|
1.0 (0.68-1.75)
|
1.12 (0.76-2.48)
|
0.075
|
ICU days; median [IQR]
|
3.0 (2.0-3.0)
|
2.0 (2.0-3.0)
|
0.175
|
2.0 (2.0-3.0)
|
3.0 (2.0-3.0)
|
0.731
|
Extubating time (ET); Median [IQR]
|
7.0 (5.0-10.0)
|
9.0 (6.75-12.25)
|
0.029*
|
7.0 (5.0-10.0)
|
7.0 (5.0-10.0)
|
0.502
|
Days at department; Median [IQR]
|
8.0 (7.0-9.0)
|
10.00 (7.00-11.25)
|
0.025*
|
8.0 (7.0-9.0)
|
8.0 (7.0-10.0)
|
0.907
|
On pump; n(%)
|
170 (91.4)
|
23 (88.5)
|
0.711
|
104 (88.9)
|
89 (93.7)
|
0.240
|
Extracorporeal Circulation length; Median [IQR]
|
80.0 (63.0-99.0)
|
76.0 (60.0-92.0)
|
0.478
|
80.0 (62.0-101.0)
|
79.0 (63.5-93.0)
|
0.640
|
Clamp length; Median [IQR]
|
57.0 (43.0-71.0)
|
54.0 (45.0-62.0)
|
0.553
|
56.0 (42.5-74.0)
|
57.5 (43.3-65.0)
|
0.832
|
Number of grafts; Median [IQR]
|
3.0 (2.0-3.0)
|
3.0 (2.0-3.0)
|
0.749
|
3.0 (2.0-3.0)
|
3.0 (2.0-3.0)
|
0.471
|
Number of grafts; n (%)
|
|
|
1.000
|
|
|
0.709
|
I
|
13 (7.0)
|
2 (7.7)
|
|
10 (8.5)
|
5 (5.3)
|
|
II
|
70 (37.6)
|
10 (38.5)
|
|
45 (38.5)
|
35 (36.8)
|
|
III
|
97 (52.2)
|
14 (53.8)
|
|
58 (49.6)
|
53 (55.8)
|
|
IV
|
6 (3.2)
|
0 (0.0)
|
|
4 (3.4)
|
2 (2.1)
|
|
Postoperative FA (atrial fibrillation), n (%)
|
36 (19.4)
|
8 (30.8)
|
0.198
|
24 (20.5)
|
20 (21.1)
|
1.000
|
Length of postoperative hospital stay; n (%)
|
|
|
0.137
|
|
|
0.676
|
≤ 7 days
|
81 (43.5)
|
7 (26.9)
|
|
47 (40.2)
|
41(43.2)
|
|
>7 days
|
105 (56.5)
|
19 (73.1)
|
|
70 (59.8)
|
54 (576.8)
|
|
CRP values; Median [IQR]
|
|
|
|
|
|
|
Preoperative CRP (mg/dL)
|
2.1 (1.0-4.0)
|
4.8 (1.6-8.3)
|
0.007*
|
2.1 (1.0-3.8)
|
2.3 (1.2-5.4)
|
0.176
|
CRP I
|
63.8 (47.8-89.6)
|
78.6 (66.2-100.4)
|
0.046*
|
68.1 (50.1-94.6)
|
63.6 (48.0-86.6)
|
0.285
|
CRP II
|
135.2 (104.7-180.9)
|
144.3 (122.9-195.3)
|
0.188
|
135.4 (104.2-182.7)
|
140.1 (108.6-180.4)
|
0.965
|
CRP III
|
130.20 (96.65-168.13)
|
141.6 (102.4-187.8)
|
0.518
|
134.5 (97.2-180.2)
|
120.1 (95.2-165.8)
|
0.330
|
CRP IV
|
90.8 (72.3-126.8)
|
96.9 (78.4-127.0)
|
0.538
|
94.8 (76.1-132.1)
|
87.40 (69.0-115.4)
|
0.079
|
CRP V
|
69.4 (51.2-90.6)
|
70.3 (56.3-86.3)
|
0.841
|
73.6 (54.3-92.8)
|
65.7 (50.2-87.2)
|
0.159
|
CRP VI
|
52.1 (37.6-69.9)
|
52.6 (41.8-71.6)
|
0.704
|
54.1 (39.1-70.1)
|
51.6 (35.6-68.3)
|
0.529
|
Early CRP Change score
|
103.7 (86.1-145.1)
|
119.9 (96.0-150.8)
|
0.212
|
107.7 (86.5-148.1)
|
106.5 (87.8-138.5)
|
0.504
|
Persistent CRP Change score
|
68.1 (51.8- 91.1)
|
74.2 (52.1- 88.4)
|
0.834
|
70.3 (53.8- 93.4)
|
66.1 (49.8- 84.8)
|
0.134
|
Overall CRP Change score
|
89.5 (72.7- 116.2)
|
95.9 (78.6- 119.4)
|
0.419
|
93.5 (72.6- 118.4)
|
85.3 (73.8- 113.8)
|
0.209
|
Data are presented as counts (n) and percentages (%) for categorical variables and as mean ± standard deviation (SD) or median and interquartile range (IQR) for continuous variables. Statistical analysis was performed by Pearson χ2 or Fisher exact test for categorical variables and by Mann-Whitney U test or Kruskal-Wallis 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; PRIME-MD, Primary Care Evaluation of Mental Disorders.* Statistically significant P-values. |
3.4. The predictive role of baseline depressive symptoms and changes in CRP values on the patient’s postoperative hospital length of stay
The results from three different logistic regression models [non-adjusted, age and sex-adjusted and fully adjusted model (current smoking status, EuroSCORE-II, pre-operative (baseline) hemoglobin levels, diabetes, the use of β-blockers, extubation/ventilation time, and postoperative atrial fibrillation)] predicting the postoperative LOS are presented in Table 4. Non-adjusted binary logistic regression analysis showed that when compared to the non-depression group (BDI-II ≤ 13), classified by the Beck Depression Inventory, patients in the mild to severe depression group (BDI-II > 13), had more than two times greater odds (OD = 0.2094, P = 0.113) of a postoperative hospital stay longer than one week. Their odds ratio remained similar (OD = 2.033 fold, P = 0.152) to the age and gender-adjusted models; however, in both models the obtained values were not statistically significant, and the only variable significantly associated with the prolonged length of stay was the age of the patient undergoing the CABG procedure (OD = 1.082, P < 0.001). The fully adjusted model encompassing the following covariables significantly correlated with postoperative LOS were: age (Spearman's r = 0.281, P < 0.001), current smoking status (r = - 0.213, P = 0.002), EuroSCORE-II value (r = 0.318, P < 0,001), preoperative (baseline) hemoglobin levels (r = -0.230, P = 0.001), diabetes (r = 0.178, P = 0.009), the use of β-blockers (r = -0.163, P = 0.018), ventilation time (r = 0.165, P = 0.016) and postoperative atrial fibrillation (r = 0.242, P< 0.001); (data not shown), with the exception of age that was already incorporated into EuroSCORE-II, the mild to severe depression group (BDI-II > 13) exhibited only 1.127 higher odds of postoperative hospital stay of longer than one week which remained statistically nonsignificant (Table 4).
However, as largely expected, the fully adjusted model revealed EuroSCORE-II values (OR = 1.557, CI = 1.065 - 2.276, P = 0.022) and postoperative atrial fibrillation (OR = 2.546, CI = 1.015 - 6.384; P = 0.046) as positive predictors and current smoking status (OR = 0.222, CI = 0.083 - 0.597, P = 0.003), preoperative (baseline) hemoglobin levels (OR = 0.974, CI = 0.950 - 0.998, P = 0.034), and β-blocker medications (OR = 0.219, CI = 0.074 - 0.642, P = 0.006) as negative predictors of postoperative LOS. Additional adjustment for BMI, cardiopulmonary bypass, number of grafts and use of statin medications additionally decreased the odds of prolonged LOS (OR = 1.026, CI = 0.294 - 3.586, P = 0.967) in the mild to severe depression group (BDI-II > 13); but a EuroSCORE-II value (OR = 1.653, CI = 1.103 - 2.477, P = 0.015), current smoking status (OR = 0.232, CI = 0.085 - 0.629, P = 0.004), preoperative hemoglobin levels (OR = 0.972, CI = 0.948 - 0.997, P = 0.026) and the use of β-blocker medications (OR = 0.217, CI = 0.073 - 0.647, P = 0.006) have remained as positive and negative predictors, respectively.
Surprisingly, non-adjusted binary logistic regression analysis showed that when compared to the non-depression group (PRIME-MD ≤ 4), classified by the Primary Care Evaluation of Mental Disorders PHQ-9 test, patients in the mild to severe depression group (PRIME-MD > 4) had a lower odds ratio (OR = 0.884) of postoperative hospital stay longer than one week (Table 3). However, as in the case of the BDI-II score, the obtained values were not statistically significant. Their odds slightly increased in the age and gender-adjusted model of binary logistic regression (OR = 0.934) revealing that the age of the patient undergoing CABG procedure as the most significant predictor of prolonged postoperative hospital LOS (OR = 1.081, CI = 1.040 - 1.123, P < 0.001). In the fully adjusted model [current smoking status, EuroSCORE-II, preoperative (baseline) hemoglobin levels, diabetes, the use of β-blockers, extubation/ventilation time, and postoperative atrial fibrillation] patients in the mild to severe depression group (PRIME-MD > 4) showed even lower odds (OR = 0.654) of postoperative LOS longer than one week when compared to the non-depressed patient group (PRIME-MD ≤ 4). This model also revealed that the EuroSCORE-II value (OR = 1.578, CI = 1.087 - 2.290, P = 0.016) and postoperative atrial fibrillation (OR = 2.547, CI = 1.007 - 6.442; P = 0.048) as positive and current smoking status (OR = 0.242, CI = 0.091 - 0.643, P = 0.004), preoperative (baseline) hemoglobin levels (OR = 0.972, CI = 0.948 - 0.997, P = 0.029), and β-blocker medications (OR = 0.214, CI = 0.073 - 0.633, P = 0.005) as negative predictors of prolonged postoperative LOS.
Such was the case for the BDI-II depression score, additional adjustment of binary logistic regression analysis for BMI, cardiopulmonary bypass, number of grafts and use of statin medications have additionally decreased the odds in the mild to severe depression group (PRIME-MD > 4) for prolonged length of hospital stay (OR = 0.589, CI = 0.299 - 1.162, P = 0.127) and the EuroSCORE-II value (OR = 1.694, CI = 1.141 - 2.515, P = 0.009), current smoking status (OR = 0.254, CI = 0.095 - 0.681, P = 0.006), preoperative hemoglobin levels (OR = 0.970, CI = 0.945 - 0.995, P = 0.019) and the use of and β-blocker medications (OR = 0.210, CI = 0.070 - 0.632, P = 0.006) as positive and negative predictors, respectively.
The last three binary logistic regression analyses described in Table 4 present non-adjusted and adjusted results of binary logistic regression in the changes in “early” (1-3 postoperative day), “persistent” (4-6 postoperative day) and “overall” (1-6 postoperative days) CRP predicting the length of postoperative hospital stay.
The results showed that for every increase in early postoperative CRP units there was only a 0.5% increase in the odds of extended hospital stay in fully adjusted models, but this was not statistically significant (P = 0.233) (Table 4). Current smoking status (OR = 0.243, CI = 0.091 - 0.642, P = 0.004), EuroSCORE-II values (OR = 1.601, CI = 1.097 - 2.335, P = 0.015), lower preoperative hemoglobin levels (OR = 0.971, CI = 0.946 - 0.997, P = 0.030) and the use of β-blocker medications (OR = 0.224, CI = 0.076 - 0.663, P = 0.007) were also identified as significant predictors of prolonged postoperative hospital length of stay in this model. Additional adjustment for BMI, cardiopulmonary bypass, number of grafts and use of statin medications did not significantly alter the results obtained in the fully adjusted model.
In contrast to the results obtained for early CRP level changes, every unit increase in persistent postoperative CRP resulted in a 1.6% increase in the odds of extended hospital stay in the fully adjusted model (P = 0.006) (Table 4). Current smoking status (OR = 0.283, CI = 0.104 - 0.768, P = 0.013), EuroSCORE-II values (OR = 1.613, CI = 1.100 - 2.365, P = 0.014), lower preoperative hemoglobin levels (OR = 0.971, CI = 0.946 - 0.997, P = 0.028) and use of β-blocker medications (OR = 0.219, CI = 0.071 - 0.671, P = 0.008) were identified as well significant predictors of prolonged postoperative LOS in this model. Furthermore, in this model, additional adjustment for BMI, cardiopulmonary bypass, number of grafts and use of statin medications did not significantly alter the results obtained in the fully adjusted model. Interestingly, in the age (OR = 1.083, CI = 1.040 - 1.127, P <0.001) and gender adjusted model, female patients had more than three times (OR = 3.198; CI =1.384 - 7.390, P = 0.007) greater odds for prolonged length of stay. Female patients also had greater odds of prolonged postoperative hospital stay (OR = 2.906; CI = 1.269-6.655, P = 0.012) in the age and gender (OR = 1.087, CI = 1.044 - 1.131, P < 0.001) adjusted model for binary logistic regression of overall postoperative CRP changes.
Every increased unit in overall postoperative CRP, in the fully adjusted model, resulted in a 1.1% increase in the odds ratio for prolonged postoperative length of stay (Table 4). Current smoking status (OR = 0.265, CI = 0.099 - 0.710, P = 0.008), EuroSCORE-II value (OR = 1.617, CI = 1.105 - 2.368, P = 0.013), lower preoperative hemoglobin levels (OR = 0.970, CI = 0.945 - 0.996, P = 0.022) and the use of β-blocker medications (OR = 0.224, CI = 0.075 - 0.675, P = 0.008) were identified as significant predictors of prolonged postoperative hospital length of stay in this model as well. Also, additional adjustment for BMI, cardiopulmonary bypass, number of grafts and use of statin medications did not substantially alter the results obtained in the fully adjusted model.
Table 4
Depression symptoms and high-sensitivity C-reactive protein (CRP) as predictors of postoperative length of hospital stay.
Variable
|
|
OR
|
95% CI
|
P-value
|
BDI-II score: Non-adjusted
|
None BDI ≤13
|
1 (reference)
|
-
|
-
|
|
Mild to severe BDI> 13
|
2.094
|
0.840-5.222
|
0.113
|
BDI-II score: Age and sex-adjusted
|
None, BDI ≤13
|
1 (reference)
|
-
|
-
|
|
Mild to severe, BDI> 13
|
2.033
|
0.769-5.375
|
0.152
|
BDI-II score: fully adjusted
|
None, BDI ≤13
|
1 (reference)
|
-
|
-
|
|
Mild to severe, BDI> 13
|
1.127
|
0.330-3.856
|
0.849
|
PRIME-MD score; non-adjusted
|
None, PRIME-MD ≤ 4
|
1 (reference)
|
-
|
-
|
|
Mild to severe PRIME-MD > 4
|
0 .884
|
0 .511- 1.531
|
0 .661
|
PRIME-MD; age and gender-adjusted
|
None, PRIME-MD ≤ 4
|
1 (reference)
|
-
|
-
|
|
Mild to severe PRIME-MD > 4
|
0.934
|
0.518-1.683
|
0.820
|
PRIME-MD score; fully adjusted
|
None, PRIME-MD ≤ 4
|
1 (reference)
|
-
|
-
|
|
Mild to severe PRIME-MD > 4
|
0.654
|
0.338-1.265
|
0.208
|
Early CRP Change score
|
non-adjusted
|
1.006
|
0.999-1.013
|
0.086
|
|
Age and gender adjusted
|
1.009
|
1.002-1.016
|
0.018*
|
|
Fully adjusted
|
1.005
|
0.997-1.013
|
0.241
|
Persistent CRP Change score
|
non-adjusted
|
1.019
|
1.009-1.029
|
<0.001*
|
|
Age and gender adjusted
|
1.023
|
1.012-1.034
|
<0.001*
|
|
Fully adjusted
|
1.016
|
1.005-1.028
|
0.005*
|
Overall CRP Change score
|
non-adjusted
|
1.014
|
1.005-1.023
|
0.003*
|
|
Age and gender adjusted
|
1.018
|
1.008-1.028
|
<0.001*
|
|
Fully adjusted
|
1.011
|
1.001-1.022
|
0.038*
|
Data are presented as odds ratio (OD) and 95% confidence intervals (CI). Statistical analysis was performed by non-adjusted, age and gender adjusted and fully adjusted [current smoking status, EuroSCORE-II, preoperative (baseline) hemoglobin levels, diabetes, the use of β-blockers, extubation/ventilation time, and postoperative atrial fibrillation] binary logistic regression analysis. CRP, high-sensitivity C-reactive protein; BDI-II, the Beck Depression Inventory; PRIME-MD, Primary Care Evaluation of Mental Disorders.* Statistically significant P-values. |
3.5. Relationship of BDI-II and PHQ-9 depression scores with baseline and postoperative CRP levels
Linear regression analysis performed to examine the relationship between the BDI-II scores and preoperative and postoperative (“early”, “persistent” and “overall” postoperative response) CRP values [with smoking status, BMI, number of grafts, cardiopulmonary bypass, diabetes, preoperative hemoglobin levels, EuroSCORE-II values, prescribed medications (β-blockers and statin use), extubation time, and postoperative atrial fibrillation used as covariates] resulted with no significant resultant association. The only significant predictors detected in those models were as follows: current smoking status (t = 2.595, P = 0.010), EuroSCORE-II values (t = 2.603, P = 0.010), BMI (t = 2.112, P = 0.036) and preoperative hemoglobin levels (t = -2.714, P = 0.007) for baseline CRP; current smoking status (t = -2.490, P = 0.014), preoperative hemoglobin levels (t = 3.103 P = 0.002), postoperative atrial fibrillation (t = 2.578, P = 0.011) and preoperative CRP values (t = 2.114, P = 0.036) for early CRP change; current smoking (t = -2.402, P = 0.017), and postoperative atrial fibrillation (t = 2.131, P = 0.034) for persistent CRP change, and current smoking (t = -2.782, P = 0.006), and postoperative atrial fibrillation (t = 2.649, P = 0.009) for overall CRP change.
Linear regression analysis was performed to examine the relationship between the PRIME-MD score and preoperative and postoperative CRP values (“early”, “persistent” and “overall” postoperative response) also resulted with no statistically significant associations. Significant predictors detected in those models were as follows: current smoking status (t = 2.631, P = 0.009), the EuroSCORE-II value (t = 2.844, P = 0.005), BMI (t = 2.118, P=0.035) and preoperative hemoglobin levels (t = -2.607, P = 0.010) for baseline CRP; current smoking status (t = -2.153, P = 0.033), preoperative hemoglobin levels (t = 2.869, P = 0.005), postoperative atrial fibrillation (t = 2.559, P = 0.011) and preoperative CRP (t = 2.2205, P = 0.029) for early CRP changes; current smoking (t = -2.427, P = 0.016), and postoperative atrial fibrillation (t = 2.100, P = 0.037) for persistent CRP change, current smoking (t = -2.615 P = 0.010), and postoperative atrial fibrillation (t = 2.632, P = 0.009) for overall CRP changes.