Admission Glucose Levels and Associated Risk for Heart Failure After Myocardial Infarction in Patients Without Diabetes

Abstract

Background Dysglycemia at acute myocardial infarction (AMI) is common and is associated with mortality. Information on other outcomes is less well explored in patients without diabetes in a long-term perspective. We aimed to explore the relationship between admission glucose level and long-term outcomes in patients with AMI without diabetes in a nationwide setting. Methods and Results Patients without diabetes (n=45 468) with AMI registered in SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) and admission glucose ≤11 mmol/L (≤198 mg/dL) were followed for outcomes (AMI, heart failure, stroke, renal failure, and death) between 2012 and 2017 (mean follow-up time 3.3±1.7 years). The association between categorized glucose levels and outcomes was assessed in adjusted Cox proportional hazards regression analyses (glucose levels 4.0-6.0 mmol/L [72-109 mg/dL] as reference). Further nonfatal complications and their associated mortality were explored (patients without events served as a reference). A glucose level of 7.8-11.0 mmol/L (140-198 mg/dL) was associated with hospitalization for heart failure (hazard ratio [HR] 1.40 [95% CI, 1.30-1.51], P<0.001), renal failure (1.17; 1.04-1.33, P=0.009), and death (1.31; 1.20-1.43, P<0.001), but not with recurrent myocardial infarction (0.99; 0.92-1.07, P=0.849) or stroke (1.03; 0.88-1.19, P=0.742). Renal failure had the strongest association with future mortality (age-adjusted HR 4.93 [95% CI, 4.34-5.60], P<0.001), followed by heart failure (3.71; 3.41-4.04, P<0.001), stroke (3.39; 2.94-3.91, P<0.001), and myocardial infarction (2.08; 1.88-2.30, P<0.001). Conclusions Elevated glucose levels at AMI admission identifies patients without diabetes at increased risk of long-term complications: in particular, hospitalization for heart and renal failure. These results emphasize that glucose levels at admission could be useful in risk assessment after myocardial infarction.

Keywords: admission glucose; heart failure; myocardial infarction; prognosis.

Figure 1. Flow chart of patient selection.

Figure 2. Time to hospitalization for major adverse cardiovascular events (A) after first occurrence of MI, heart failure, stroke, or death; (B) death; (C) heart failure; (D) renal failure; (E) heart failure/renal failure; (F) MI; (G) stroke; and (H) MI/stroke after index MI by glucose levels.

Patients who died during the first 30 days were excluded. MI indicates myocardial infarction.

Figure 3. Adjusted associated HR (95% CI) for MACE (death, MI, stroke, or heart failure), death, MI /stroke, and heart failure/renal failure by glucose level strata.

Patients with blood glucose of 4–6 mmol/L (72–109 mg/dL) served as a reference group with HR 1.0. Extensive unadjusted and adjusted outcome data for single events are presented in Table S1. HR indicates hazard ratio; MACE, major adverse cardiovascular events; and MI, myocardial infarction.

Figure 4. Restricted cubic spline analyses of association between continuous glucose level and (A) major adverse cardiovascular events, (B) heart failure or renal failure, (C) heart failure, and (D) MI or stroke.

The solid line demonstrates the hazard ratio (HR) and the dotted line the 95% CI. A glucose level of 5.0 mmol/L (90 mg/dL) served as a reference (HR, 1.0).

Figure 5. Time to mortality by first clinical event (heart failure, renal failure, stroke, or myocardial infarction) after index myocardial infarction.

Patients who died during the first 30 days were excluded. Multiple events was defined as several of these events during the same hospitalization.