A RETROSPECTIVE STUDY OF THE RELATIONSHIP OF GLYCOSYLATED HEMOGLOBIN (HbA1c) AND CLINICAL OUTCOMES OF PATIENTS WITH HEART FAILURE IN A TERTIARY HOSPITAL

Abstract

INTRODUCTION
Diabetes mellitus type 2 is a risk factor for the development of cardiovascular diseases, which includes acute coronary syndrome, cerebrovascular disease and heart failure. In addition, heart failure is considered an insulin-resistant state and is associated with an increased risk for the development of diabetes mellitus type 2. There are limited studies about heart failure in the Philippines. Studies examining the relationship between Glycosylated Hemoglobin (HbA1c) and outcomes in patients with established heart failure have been limited and have reported inconsistent results. Therefore, this study will be conducted to determine the relationship between HbA1c and clinical outcomes of hospitalized patients with heart failure – both with diabetes and those without diabetes in terms of mortality, length of hospital stay, ICU admissions, respiratory failure and intubation rates. These clinical outcomes will be correlated with the HbA1c level of patients with diabetes using quintiles: Q1: HbA1c less than 6.5%; Q2: 6.6%-6.9%; Q3: 7.0%-7.9%; Q4: 8.0%-8.9%, and Q5: HbA1c 9.0% and above.

METHODOLOGY
The study utilized a single-center retrospective analysis of patients admitted to a tertiary hospital from February 1, 2022 to February 28, 2023. Data were collected through chart review of the patients. Inclusion criteria were patients more than 18 years of age. Exclusion criteria were severe anemia (hemoglobin of 8.0 mg/dl and below) and chronic steroid use. The study included 283 patients with heart failure, of which 158 patients were patients with diabetes mellitus type 2 and 125 patients were patients without diabetes.

RESULTS
Results showed that the lowest mortality risk was seen among those patients with modest glucose control at quintile 3 (HbA1c of 7.0%-7.9%), while the highest mortality risk was seen in quintile 4 (HbA1c 8.0%-8.9%). Similarly, this quintile group had the lowest risk of ICU admission and respiratory failure.

CONCLUSION
Based on the results of this retrospective study, there appears to be an association between mortality and HbA1c, as those with modest glucose control had the lowest mortality risk. Furthermore, significantly elevated HbA1c was also associated with an increased risk of mortality. This study has also shown some mortality risk even among heart failure patients with good glycemic control.