The Prevalence Of Hyperglycemia In Non-Diabetic Patients In The Cardiac Intensive Care Unit (Icu) After Cardiac Surgery At Tertiary Care Hospitals Peshawar

Pakistan Journal of Medical & Cardiological Review https://pakjmcr.com/index.php/1/about Online ISSN Print ISSN 3007-2387 3007-2379 Vol. 4 No. 4 (2025) Pakistan Journal of Medical & Cardiological Review Page 1820 The Prevalence Of Hyperglycemia In Non-Diabetic Patients In The Cardiac Intensive Care Unit (Icu) After Cardiac Surgery At Tertiary Care Hospitals Peshawar Fawad Alam* Anesthesia Technologist, Khyber Teaching Hospital, Peshawar Email: [email protected] Amin Arsalan Anesthesia Technologist, Hayatabad Medical Complex, CRC, Peshawar Safi Ullah Anesthesia Technologist, PIMS Cardiac Surgery, Peshawar Usman Khan Anesthesia Technologist, Hayatabad Medical Complex, CRC, Peshawar Muhammad Sadeeq Consultant Surgeon Cardiology, Hayatabad Medical Complex, CRC, Peshawar Background: Postoperative hyperglycemia is a welldocumented risk factor for complications following cardiac surgery, even in patients without a prior history of diabetes. This study aimed to assess the prevalence of postoperative hyperglycemia in non-diabetic patients undergoing cardiac surgery. Methods: A total of 101 non-diabetic patients who underwent cardiac surgery were included in this observational study. Demographic, surgical, and glycemic data were collected and analyzed to identify patterns and potential risk factors associated with postoperative hyperglycemia. Results: Of the patients studied, 92.1% had normal preoperative glucose levels, yet 63.4% developed elevated or high glucose levels postoperatively. Patients who developed hyperglycemia were notably older (mean age 40.7 years) compared to those who maintained normal glucose levels (mean age 30.5 years), while body mass index (BMI) showed no significant difference between groups. CABG was the most frequently performed procedure (58.4%). A progressive increase in BMI and weight was observed across age groups. Conclusion: The findings indicate that postoperative hyperglycemia is common in non-diabetic cardiac surgery patients, with older age identified as a significant risk factor. These results highlight the importance of routine glucose monitoring and early management in non-diabetic individuals to reduce the risk of adverse outcomes. Further research is Abstract Author Details Keywords: Post-Operative Hyperglycemia, Cardiac Surgery, Non-Diabetic Patients, CABG, Glycemic Control, CICU Received on 10 Nov 2025 Accepted on 05 Dec 2025 Published on 15 Dec 2025 Corresponding E-mail & Author*: Fawad Alam* Anesthesia Technologist, Khyber Teaching Hospital Peshawar [email protected] Page 1821 recommended to explore additional predictive factors and long-term effects of stressinduced hyperglycemia. Introduction Stress-induced hyperglycemia (SIH) is a frequent metabolic disturbance observed in hospitalized and surgical patients, even in those without a prior diagnosis of diabetes. Acute physiological stress triggers the release of catecholamines, cortisol, glucagon, and growth hormone, resulting in enhanced hepatic gluconeogenesis, reduced peripheral glucose uptake via GLUT-4 transporters, and impaired insulin secretion. This dysregulated metabolic state contributes to elevated circulating glucose levels that may worsen clinical outcomes, particularly among critically ill patients and those undergoing cardiac surgery (1,2). Mounting evidence demonstrates that hyperglycemia exacerbates oxidative stress and inflammatory responses, both of which contribute to myocardial injury, endothelial dysfunction, and impaired tissue recovery. Although traditionally considered a transient epiphenomenon, SIH has shown independent associations with increased mortality, postoperative renal dysfunction, neurological injury, deep sternal wound infections, and arrhythmias after cardiac surgery. Importantly, even non-diabetic patients frequently develop significant postoperative hyperglycemia due to the profound inflammatory and metabolic burden imposed by cardiopulmonary bypass (CPB), anesthesia, surgical trauma, and increased catecholamine exposure (3,4). As cardiac surgery volumes rise globally particularly for CABG, TAVR, and mitral valve interventions the identification and management of peri-operative hyperglycemia have become crucial to improving patient outcomes. Contemporary guidelines recommend maintaining intraoperative and postoperative glucose levels below 180 mg/dL; however, optimal glucose targets, timing of insulin initiation, and intensity of insulin therapy remain subjects of ongoing debate. Understanding the clinical significance of hyperglycemia in both diabetic and non-diabetic patients remain essential to reducing postoperative morbidity and mortality (5,6). Several studies have consistently demonstrated that peri-operative hyperglycemia is a strong and independent predictor of adverse outcomes following cardiac surgery. Thiele et al. (2015) reported that higher admission blood glucose levels were significantly associated with increased mortality, postoperative renal failure, and stroke. Similarly, doesn’t et al. (2005) observed that elevated intraoperative glucose levels during CPB independently predicted mortality and major complications in both diabetic and non-diabetic individuals. Additional findings from Donatella et al. (2008) highlighted that patient with metabolic syndrome experienced universal postoperative insulin resistance and significantly higher CPB-associated glucose elevations, indicating the enhanced vulnerability of high-risk metabolic phenotypes (7,8). Pharmacological factors also influence postoperative glucose trends. Tien et al. (2016) demonstrated that dexamethasone administration significantly increased postoperative glucose levels in both diabetic and non-diabetic patients when compared with ondansetron. Beyond drug effects, multiple mechanisms—including inflammatory cytokine release, acute insulin resistance, and enhanced hepatic glucose output— contribute to postoperative hyperglycemia. Collectively, the literature underscores that peri-operative hyperglycemia is not merely a benign reflection of illness severity but a modifiable risk factor with clear implications for postoperative recovery (9). Effective peri-operative glucose management has demonstrated substantial clinical benefits across diverse cardiac surgical populations. Continuous insulin infusion protocols have been linked with reduced deep sternal wound infections, shorter hospital stays, lower rates of recurrent ischemia, improved long-term survival, and decreased postoperative morbidity. Tight glucose regulation also mitigates oxidative Page 1822 stress, reduces inflammatory burden, enhances immune function, and supports optimal wound healing. Emerging therapeutic options, such as GLP-1 receptor agonists, provide additional promise by improving glycemic stability with minimal hypoglycemia risk, suggesting expanding opportunities for safer and more effective peri-operative metabolic care (10). Peri-operative hyperglycemia is a prevalent and clinically significant condition among cardiac surgery patients, irrespective of pre-existing diabetic status. The evidence strongly supports its role as an independent predictor of mortality, renal dysfunction, neurological complications, and postoperative infections. Surgical stress, CPB, inflammatory activation, and medication effects collectively contribute to the development of SIH, emphasizing the need for early recognition and targeted glycemic control. Optimizing peri-operative glucose management may improve patient outcomes, reduce postoperative complications, and enhance recovery following complex cardiac procedures. Continued research is essential to refine glucose targets and develop therapeutic strategies that maximize benefit while minimizing risks. MATERIALS AND METHODS This prospective observational study was conducted over a six-month period in the Cardiac Intensive Care Units (ICUs) of Hayatabad Medical Complex (HMC) and Peshawar General Hospital (PGH), both tertiary-care centers providing 24-hour multidisciplinary management for critically ill cardiac patients. The study aimed to determine the prevalence of postoperative hyperglycemia among non-diabetic individuals admitted to the cardiac ICU following cardiac surgery. A total of 101 nondiabetic patients aged above 15 years, recovering after various cardiac surgical procedures, were selected through convenient sampling, ensuring accessibility to the participants while maintaining a 90% confidence level and a 1% margin of error. Patients included were those with a confirmed non-diabetic status prior to surgery and admitted to the cardiac ICU after the procedure; both male and female individuals were eligible. Exclusion criteria comprised known diabetes mellitus, preoperative glucose-lowering medications, long-term steroid therapy, preoperative steroid use, emergency cardiac surgeries, refusal to participate, and age below 15 years. Institutional approval was obtained from the Research Committee of IQRA National University, as well as permissions from HMC (CRC) and PGH, after which data were collected using a structured questionnaire administered within the ICU setting (11). RESULTS: Demographic Analysis The demographic analysis of 101 patients shows a strong male predominance (75.2%) and identifies the 36–50 years age group as the largest cohort (51.5%). A clear agerelated trend is observed, with both BMI and weight increasing steadily across age groups from 19.2 kg/m² and 45.8 kg in the youngest group to 27.2 kg/m² and 70.8 kg in the oldest group while gender differences remain minimal. These findings indicate that age is the primary factor influencing anthropometric variation in this cardiac surgical population. Table 1: Descriptive Statistics of Demographic information Age Group Gender N Mean Age SD Age Mean BMI SD BMI Mean Weight SD Weight Page 1823 16-25 Male 10 19.3 3.4 19.2 5.7 45.0 13.4 16-25 Female 3 19.7 1.5 19.2 0.4 48.0 5.3 26-35 Male 8 31.8 2.9 23.7 4.1 68.0 13.0 26-35 Female 6 33.0 6.1 22.3 6.0 57.7 22.3 36-50 Male 37 43.4 5.7 27.0 4.7 77.1 13.5 36-50 Female 15 43.6 4.9 27.1 6.4 67.9 18.5 51-75 Male 21 61.1 6.6 27.2 5.5 71.2 13.8 51-75 Female 1 58.0 25.0 58.0 Figure 1 shows Patient Distribution by Age group and Gender Figure 4.2 shows mean BMI by age group and gender Page 1824 Surgery Type Analysis The surgery type distribution shows a strong concentration toward Type 1 procedures, which account for over half of all surgeries (58.4%), while all other surgery types occur at much lower frequencies. Type 11 is the next most common but still represents only 7.9% of cases, and several specialized procedures, including DVR and MVR, were performed on just one or two patients. Patient characteristics vary across surgery categories, with BMI ranging from 20.1 kg/m² in Type 5 to 30.5 kg/m² in Type 14, and mean age spanning from 26 years in Type 6 to 53 years in MVR cases. Although surgery durations typically fall between 2.0 and 2.2 units, some types show shorter or longer times. Overall, the pattern indicates a facility highly experienced in Type 1 surgeries while still managing a diverse array of less frequent procedures. Table 2: Frequency and Average of Surgical Procedures Surgery Type N Percentage (%) Mean Age Mean BMI Mean Duration Type 1 59 58.4 48.2 27.1 2.2 Type 11 8 7.9 38.1 23.2 2.2 Type 6 5 5.0 26.0 24.1 1.8 Type 3 4 4.0 37.8 20.9 2.2 Type 4 4 4.0 35.2 20.9 2.5 Type 10 3 3.0 36.0 29.2 1.7 Type 14 3 3.0 38.7 30.5 2.0 Type 5 3 3.0 28.7 20.1 1.7 13 2 2.0 18.5 16.2 2.5 7 2 2.0 52.0 26.8 2.5 12 1 1.0 46.0 28.5 1.0 15 1 1.0 34.0 14.9 2.0 16 1 1.0 17.0 17.9 1.0 17 1 1.0 19.0 16.2 1.0 8 1 1.0 42.0 21.0 2.0 Page 1825 9 1 1.0 22.0 24.2 2.0 DVR 1 1.0 47.0 27.8 2.0 MVR 1 1.0 53.0 24.7 1.0 Figure 3: show Number of Patients by Surgery Distribution Table 3 Various Surgical Procedure Key TYPE SURGICAL PROCEDURE 1 Coronary Artery Bypass Grafting (CABG) 2 Mitral Valve Replacement (MVR) 3 Double Valve Replacement (DVR) 4 Atrial Valve Replacement (AVR) and CABG 5 Vascular Surgery 6 Atrial Valve Replacement 7 LAD myotomy 8 Coarctation of Aorta 10 CABG and MVR 11 ASD Closure 12 VSD Closure 13 RA Myxoma Excision Clinical Outcomes Analysis The clinical outcomes analysis shows a significant rise in post-operative hyperglycemia despite most patients (92.1%) having normal pre-operative glucose levels. Only 8.6% of these patients maintained normal glucose post-operatively, while Page 1826 the majority (63.4%) developed some form of hyperglycemia, including high levels above 220 mg/dl and severe elevations exceeding 300 mg/dl. Among patients who were already elevated pre-operatively, most progressed to higher levels after surgery. Those who developed high glucose post-operatively were generally older (mean age 40.7 years) compared to patients who maintained normal glucose (mean age 30.5 years), suggesting that surgical stress, suboptimal perioperative glucose management, and age-related metabolic factors may be contributing to poor glycemic outcomes. Table 4: shows the blood Glucose Level changes from pre-operative to postoperative and their frequency, BMI, Average Pre-Op BGL Post-Op BGL N Percentage (%) Mean Age Mean BMI Normal 220-280 40 39.6 40.7 25.1 Normal Exceed 300 25 24.7 39.6 26.5 Normal 180-220 19 18.8 50.2 24.0 Normal Less than 120 1 1.0 24 18.25 Normal Normal 8 7.9 30.5 24.6 Elevated 220-280 5 5.0 57.6 29.7 Elevated Normal 1 1.0 55.0 37.3 Elevated 220-280 1 1.0 59.0 21.8 Elevated Exceed 300 1 1.0 46.0 20.0 Figure 4 Show blood glucose level changes from Pre op to Post Op Clinical Outcomes Analysis Page 1827 The statistical analysis confirmed strong and significant associations among key variables. A one-way ANOVA demonstrated highly significant BMI differences across age groups (F = 9.638, p < 0.001), with age accounting for about 23% of BMI variance. Post-hoc Tukey tests showed that the youngest group (16–25 years) had significantly lower BMI than the 36–50 and 51–75 age groups, while no difference was found between the two older groups, indicating BMI tends to plateau after age 35. Correlation analysis further supported these findings, revealing a moderate positive correlation between age and BMI (r = 0.308), a very strong correlation between weight and BMI (r = 0.829), and a moderate correlation between height and weight (r = 0.506), all statistically significant. These results collectively validate the observed age-related trends and anthropometric relationships. Figure 5 shows Moderate Correlation with BMI Figure 6 Shows Age vs BMI relationships Page 1828 Figure 7 shows the correlation matrix of 8 patients who’s hyperglycemic pre operatively with Age, Weight, BMI and Post-operative blood glucose level Statistical Tests Analysis The analysis leads to several key clinical recommendations aimed at improving surgical outcomes. The most urgent priority is strengthening perioperative glucose management, as 63.4% of patients with normal pre-operative glucose developed postoperative hyperglycemia. This requires more frequent glucose monitoring, standardized insulin protocols, and early endocrinology involvement, especially for severe cases. Age-related increases in BMI highlight the need for ageand BMI-based perioperative planning, including tailored nutritional assessment, modified anesthesia strategies, and closer post-operative monitoring for older patients. The strong predominance of Type 1 surgeries supports developing specialized care pathways and standardized protocols to enhance efficiency and safety. Furthermore, gender-specific risk assessments, improved data collection to reduce missing glucose values, BMIbased surgical risk stratification, and multidisciplinary care involving endocrinologists, nutritionists, and specialized nurses are recommended to optimize patient care. DISCUSSION Postoperative hyperglycemia is a well-recognized complication following cardiac surgery, even among patients without pre-existing diabetes. Stress-induced rises in glucose levels can impair immune function, delay wound healing, prolong ICU stay, and increase morbidity. The present study, conducted on 101 non-diabetic patients undergoing various cardiac surgeries in two tertiary care hospitals in Peshawar, highlights the substantial burden of postoperative hyperglycemia and its clinical implications. Data were collected in the cardiac ICUs of Hayatabad Medical Complex and Peshawar General Hospital over six months (12). A key finding of this study is that although 92.1% of patients had normal preoperative glucose levels, **63.4% developed postoperative hyperglycemia**, demonstrating