Of the 4019 patients initially enrolled in the study, 12 received emergency PCI, 148 were administered CM before the operation, 70 were allergic to CM, 58 had severe renal insufficiency, 66 had severe cardiac insufficiency, 13 had malignant tumors, and 47 had recently used drugs leading to renal toxicity. The data of 68 patients were incomplete (Group 1: n = 11; Group 2: n = 16; Group 3: n = 20; Group 15: n=; Group 5: n = 8). The main reason for the missing data in most patients was attributed to their early discharge, which resulted in imperfect Scr levels. A total of 3437 patients were included in the study and 3185 were followed up; statistical analysis was performed based on the data of 3437 patients. There were no significant differences in the rate of major adverse events among the groups comprising the 3185 patients who were followed up.
Baseline clinical characteristics
There were no significant differences in the baseline characteristics among the 5 groups (age, male sex, smoking, left-ventricular ejection fraction (LVEF) < 45%, hypertension, contrast volume; TG, TC, HDL-C, and LDL-C levels; hydration levels; the use of beta-blockers, ACEI/ARB, CCBs, hypoglycemic agents, and insulin) before operation. Patients with elevated preoperative FBG levels were found to have higher BMI (p = 0.001) HbA1c (P < 0.0001) and Scr (P = 0.038). In addition, patients with higher blood glucose levels were found to have undergone PCI more often (P = 0.002). (Table 1)
Table 1. Comparisons of baseline characteristics between the five groups.
![](https://myfiles.space/user_files/58893_b39df98f09c4a4bb/58893_custom_files/img1626678316.png)
Table 1. Data are expressed as mean ± SD or n (%). FBG: Fasting Blood Glucose; ACEI: angiotensin-converting enzyme inhibitor; ARB: angiotensin receptor blocker; BMI: body mass index; TC: total cholesterol; TG: triglyceride; HDL-C: high-density lipoprotein cholesterol; LDL-C: low-density lipoprotein cholesterol; LVEF: left ventricular ejection fraction; CCB: calcium channel blockers; PCI: Percutaneous Coronary Intervention; HbA1c: glycosylated hemoglobin.
Comparison of Scr levels and CIN incidence among groups
Patients with elevated preoperative FBG had higher basal Scr (p = 0.038) and higher Scr levels at 48 h and 72 h after CAG/PCI. We also compared the percent change in mean Scr compared with the baseline creatinine levels at 48 and 72 h in the 5 groups and found that the difference was statistically significant (p < 0.0001). The incidence of CIN in the 5 groups of patients was 6.7%, 10.5%, 17.5%, 18.4%, and 23.2%. Univariable logistic regression analysis was used to analyze the factors affecting CIN. CIN was chosen as the dependent variable, and factors that could affect CIN development (male gender, age, LVEF < 45%, contrast volume, hydration amount, basal Scr, BMI, hypertension, HbA1c, ACEI/ARB, CCB, PCI, and preoperative FBG) were considered as independent variables. The significant influencing factors from univariate analysis were selected for multivariate logistic regression analysis [odds ratio (OR) = 1.008 (1.001–1.016), p = 0.028)]. (Table 2)
Table 2. Univariable and multivariable logistic regression analyses analysis for certain confounding factors of CIN.
![](https://myfiles.space/user_files/58893_b39df98f09c4a4bb/58893_custom_files/img1626678370.png)
Table 2. BMI: body mass index; LVEF: left ventricular ejection fraction; PCI: Percutaneous Coronary Intervention; HbA1c: glycosylated hemoglobin; ACEI: angiotensin-converting enzyme inhibitor; ARB: angiotensin receptor blocker; CCB: calcium channel blockers. FBG: Fasting Blood Glucose.
The trend test was used to further demonstrate the relationship between preoperative FBG levels and the incidence of CIN. It can be seen from the changes in OR (1.000, 1.425, 2.489, 2.704, 3.234) that the incidence of CIN increased significantly (p < 0.0001) with an increase in the preoperative FBG levels. (Table 3)
Table 3. The logistic regression analysis and the trend test
![](https://myfiles.space/user_files/58893_b39df98f09c4a4bb/58893_custom_files/img1626678414.png)
Table 3. Model 1 was not adjusted. Model 2 was adjusted for age, male, hydration amount, CM. Model 3 additionally was adjusted for PCI, BMI, HbA1c and hypertension.
subgroup analysis
Multivariate analysis was used to confirm the association between preoperative FBG levels and the risk of CIN after adjusting for the baseline confounding factors. Our results showed that patients with elevated preoperative FBG levels (above the median value 150 mg/dL) in the main high-risk subgroups, such as BMI (> 23.9 kg/m2: adjusted OR = 2.835 (1.533–5.242), p = 0.001), age (≥ 65: adjusted OR = 2.075 (1.187–3.629), p = 0.010), hypertension (hypertension: adjusted OR = 2.294 (1.337–3.936), p = 0.003), and PCI (PCI: adjusted OR = 2.298 (1.241–4.253), p = 0.008) had a higher risk of CIN. (Fig. 2)
Previous research shows that in diabetic patients undergoing CAG/PCI, elevated HbA1c is independently associated with the risk of CIN, and when HbA1c > 9.5%, the incidence of CIN trends increase.(19) Based on previous research, we further studied the relationship between preoperative FBG levels and CIN in the HbA1c subgroup. There was a significant relationship between higher preoperative FBG levels and greater risk for CIN in patients with HbA1c 6.5%-8.0% (P = 0.007) and HbA1c 8.0%-9.5% (P = 0.011). However, the relationship between preoperative FBG and CIN was not significant among patients HbA1c 9.5%-11.0% (P = 0.735) and HbA1c > 11.0% (P = 0.867). (Fig. 3)