**Abstract**

Impaired glucose metabolism and its consequence diabetes mellitus is still challenging the health care system worldwide. According to the International Diabetes Federation in 2021, the number of adult people living with diabetes was approximately 537 million and 860 million adults had prediabetes. It is predicted that numbers will rise in the future. Numerous researches have shown that prediabetes and diabetes mellitus are serious risk factors for cardiovascular diseases. Lots of epidemiological evidence figured out that diabetes mellitus is associated with the risk of developing heart failure. Diabetes mellitus is highly prevalent among patients with heart failure. Moreover, several anti-diabetics (anti-prediabetic) medications are contributing their share into developing heart failure by increasing risk of mortality and hospitalization for heart failure. This chapter will discuss the connection between prediabetes, diabetes mellitus, and chronic heart failure.

**Keywords:** diabetes mellitus type 2, prediabetes, chronic heart failure, diabetes risk factors, diabetes management

### **1. Introduction**

Diabetes mellitus (DM) is one of the major healthcare problems worldwide. According to the International Diabetes Federation (IDF) 2021 Atlas, 537 million adults (20–79 years) are living with diabetes. This number is predicted to rise to 783 million by 2045 [1]. Of persons with diabetes, 21.4% were not aware of or did not report having diabetes, and only 15.3% of persons with prediabetes reported being told by a health professional that they had this condition [2]. The prevalence of DM type 2 (T2D) is overwhelming. It is accounted for more than 90% of diabetes cases all over the world [1]. High incidence of T2D is thought to be because of population aging, lack of physical activity, urbanization, and obesity [3].

DM is diagnosed by using following criteria: fasting plasma glucose level of ≥126 mg/ dl, glycated hemoglobin (HbA1c) level of ≥48 mmol/mol, and 2-hour plasma glucose after 75 g oral glucose load (oral glucose tolerance test-OGTT) level of ≥11.1 mmol/l.

Diabetes should be diagnosed if one or more diagnostic criteria are met [1]. Symptoms of diabetes include thirst, fatigue, polyuria, hunger, weight loss, blurred vision, etc.

The classification of DM is not unified and there are some differences between proposed classification by the American Diabetes Association (ADA) [4], IDF [1], and the World Health Organization (WHO) [3]. Precise classification is important for identifying the individual treatment approach since sometimes it is quite difficult to distinguish types of DM [4].

Variety of genetic and environmental factors can lead to the progressive loss of ß-cell mass and/or function that manifest as hyperglycemia which result in DM. Deficient ß-cell insulin secretion, often on the background of insulin resistance, appears to be the common pathophysiological factor for T2D. T2D is associated with insulin secretory defects related to genetics, inflammation, and metabolic stress [4].

### **2. Risk factors for diabetes mellitus**

Risk factors for DM include adults, with a history of cardiovascular disease (CVD), hypertension (≥140/90 mmHg or on therapy for hypertension), HDL cholesterol level < 35 mg/dL (0.90 mmol/L) and/or a triglyceride level > 250 mg/dL (2.82 mmol/ L), physical inactivity, and other clinical conditions associated with insulin resistance (e.g., severe obesity, acanthosis nigricans) and etc. Also, patients with prediabetes and women who were diagnosed with gestational diabetes mellitus are at risk of diabetes [4]. People living with diabetes are at risk of macrovascular complications such as CVD and microvascular complications (such as diabetic kidney disease, diabetic retinopathy, and neuropathy). These complications lead to increased mortality, blindness, kidney failure, and decreased quality of life in individuals with diabetes [5]. T2D is a common metabolic disease leading to diabetic myocardiopathy and atherosclerotic cardiovascular disorder. These conditions may induce heart failure through a range of mechanisms along with myocardial infarction (MI) and chronic pressure overload [6].

Atherosclerotic cardiovascular diseases are determined as coronary artery disease, cerebrovascular disease, and peripheral artery diseases. Among patients with DM atherosclerotic CVD remains the main cause of death and disability [7]. This results in \$37.3 billion in cardiovascular-related spending in patients with diabetes per year [8]. CVD and T2D share several common pathophysiological features such as insulin resistance, inflammation, oxidative stress, hypercoagulability, high blood pressure (BP), dyslipidemia, and obesity. Classical cardiovascular risk factors, such as dyslipidemia, hypertension, and obesity can also raise the risk of T2D [6].

Although T2D and heart failure (HF) are each individually associated with morbidity and mortality, they often occur together, which further worsens adverse patient outcomes, quality of life, and costs of care [9].

Observational studies of patients with DM (predominantly type 2) have identified an approximately two to fourfold risk of HF compared to individuals without DM [10]. While the relative risk of HF in patients with DM compared with patients without DM is higher in younger individuals [11], the frequency of HF is higher in older adults with DM who were ≥ 65 years of age [12].

Although studies have shown an association between poor glycemic control and risk of HF, improved glucose control has not been shown to reduce incident HF. A meta-analysis including 27,049 patients with T2D found that more intensive glucose control, compared with less intensive control, did not decrease incident HF or mortality, although major cardiovascular events (primarily MI) were decreased [13].

#### *Diabetes Mellitus Type 2, Prediabetes, and Chronic Heart Failure DOI: http://dx.doi.org/10.5772/intechopen.106391*

Glycemic control is assessed by HbA1c level measurement, continuous glucose monitoring (CGM) using either time in range and/or blood glucose monitoring. In a clinical scenario HbA1c measurement is used more often. The HbA1c measurement should be performed in all diabetes patients at initial assessment and once in every 3 months. Measurement of HbA1c every 3 months determines whether patients' glycemic targets have been achieved and maintained. The HbA1c checking may have limitations in patients with medical conditions that can affect red blood cell turnover (hemodialysis, erythropoietin therapy, etc.). In such cases plasma blood glucose measurements are conducted by using BGM by fingerstick and CGM. Glycemic targets should be determined individually in each diabetes patient. There is evidence that more intensive glycemic control in newly diagnosed diabetes patients can be beneficial in reducing long-term CVD [14]. However, available data show that strict glycemic control in patients with established DM does not eliminate the risk of developing HF [15]. Overall, there is obscurity on choosing glycemic targets in diabetes mellitus with HF.

Prognosis in patients with HF and DM having DM led to worse outcomes in comparison with those who did not have DM among patients with HF. This was also demonstrated by randomized trial data in patients with HF with reduced ejection fraction (HFrEF; LVEF ≤40%) or HF with preserved ejection fraction (HFpEF) [9, 16–22].

A study of data from the Candesartan in Heart Failure-Assessment of Reduction in Mortality and morbidity (CHARM) program on outcomes in patients with HF found that concurrent DM was associated with a greater increased risk of cardiovascular death or HF hospitalization in patients with LVEF >40% than in patients with LVEF ≤40% [21]. The risk by DM was similar in the two groups for all-cause mortality.

In the Prospective Comparison of ARNI with ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure (PARADIGM-HF) trial with patients with HFrEF, there was an increased risk of the primary outcome of HF hospitalization or cardiovascular mortality in patients with previously undiagnosed DM or known DM [19].

It has been shown that, there is disturbingly high prevalence, incidence, and mortality for HF in individuals with diabetes [12]. DM patients who developed HF had poor prognosis.

It has been shown that, there is disturbingly high prevalence, incidence, and mortality for heart failure in individuals with diabetes [12]. DM patients who developed HF had poor prognosis.
