Undiagnosed Diabetes Mellitus in Patients Presenting with Acute Coronary Syndrome: Frequency and Association with In-Hospital Outcomes

Abstract

Objectives: To determine the frequency of undiagnosed diabetes mellitus (UDM) among patients presenting with acute coronary syndrome (ACS) and to evaluate its association with in-hospital adverse cardiovascular outcomes. Methodology: This prospective hospital-based observational study with in-hospital follow-up was conducted at the Department of Cardiology, Khyber Teaching Hospital, Peshawar. A total of 102 patients aged 40–80 years presenting with ACS and without previously diagnosed diabetes were enrolled consecutively. UDM was defined using laboratory criteria including fasting plasma glucose ≥126 mg/dL, random plasma glucose ≥200 mg/dL on two occasions, or HbA1c ≥6.5%. Patients were followed until discharge for in-hospital adverse cardiovascular events (ACE), including cardiovascular death, reinfarction, stroke/transient ischemic attack (TIA), acute heart failure, and arrhythmias. Multivariable logistic regression was performed to identify independent predictors of ACE. Results: UDM was identified in 12.7% of ACS patients. It was significantly associated with age ≥60 years (OR 5.14; p=0.011), obesity (BMI ≥30 kg/m²; OR 6.00; p=0.018), and positive family history of diabetes (OR 5.14; p=0.011). Patients with UDM had significantly higher fasting glucose, random glucose, and HbA1c levels (all p<0.001). UDM was associated with increased odds of in-hospital ACE (OR 4.87; p=0.009), acute heart failure (OR 3.52; p=0.041), and arrhythmias (OR 5.03; p=0.028). After adjustment for confounders, UDM remained an independent predictor of ACE (adjusted OR 3.82; p=0.037). Conclusion: UDM is relatively frequent among ACS patients and independently associated with worse in-hospital outcomes. Early identification using HbA1c during ACS admission may improve risk stratification and clinical management.