Diabetes is a group of metabolic diseases and a serious, long-term (chronic) condition which characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. ^{1 – 3} Based on the 10th edition of the International Diabetic Federation (IDF) Atlas, the prevalence of diabetes is estimated to be 537 million adults aged 20–79 years worldwide (10.5%). This includes both type 1 and type 2 diabetes as well as diagnosed and undiagnosed diabetes. The adult population with diabetes aged between 20-79 years is estimated to be 19,465,100 in Indonesia. Instead, the prevalence of diabetes among the ages–20-79 years is 10.6% (of the total adult population aged 20-79 years is 179,720,500). In other words, one in nine people in Indonesia had diabetes. ² T2DM is one of the most important causes of morbidity and mortality worldwide. ⁴

Prediabetes is a condition that results in high BGL and often leads to T2DM. ⁵ People with prediabetes have high BGL (are below the amount needed to be diagnosed with diabetes, but they are at a higher risk of getting diabetes. ⁶ According to the World Health Organization (WHO), prediabetes is an intermediate level of high blood sugar. They use two specific tests to define it: impaired FBGL, which means BGL of 6.1 to 6.9 mmol/L (110–125 mg/dL) before a meal, or impaired OGTT, which mean OGTT of 7.8 to 11.0 mmol/L (140–199 mg/dL) two hours after eating 75 g of oral glucose. ⁷

According to the American Diabetes Association (ADA), the criterion for identifying impaired FBGL between 5.6 and 6.9 mmol/L (100-125 mg/dL), impaired OGTT between 7.8 and 11.0 mmol/L (140-199 mg/dL), and HbA1c levels between 5.7% and 6.4% (39-47 mmol/mol). ^{8 , 9} Both definitions rely on FBGL measurements, 2-hour plasma glucose concentrations during an OGTT, and HbA1c concentrations. ¹⁰ In Indonesia, the diagnostic criteria for prediabetes align with those established by the ADA. ¹¹ The significance of Impaired FBGL and impaired 2-hour postprandial OGTT is threefold: they signal an elevated chance of developing T2DM in the future, indicative of an existing heightened risk of cardiovascular disease (CVD), and identifying therapies that can prevent the onset of T2DM. ²

Individuals with Impaired FBGL and impaired OGTT are at a high risk of developing T2DM, with up to 50% within five years. ^{8 , 9} Untreated T2DM for a prolonged time can lead to complications such as retinopathy, neuropathy, CVD, or stroke. ^{12 – 14} These chronic implications contribute to diabetes distress and health expenditures. ^{15 , 16} Diabetes distress is a hidden emotional burden in DM. ¹⁷ Healthcare expenditure for people with diabetes is expected to reach 1,054 billion USD by 2045. ¹⁸ The cost of managing individuals with T2DM and complications is two times higher than that for individuals without complications. ^{19 , 20}

Risk factors for prediabetes include BMI, waist circumference, ethnicity, family history, and sex. ^{2 , 9 , 21} Other risk factors include hypertension, low levels of HDL cholesterol, smoking, and low levels of education and income. ²² According to the RISKESDAS (National Basic Health Research) Indonesia, the increase in diabetes data is in line with the rise in obesity rates, a risk factor for diabetes, from 14.8% to 21.8% in 2013-2018. In addition, it is also in line with the increase in BMI from 11.5% to 13.6% and central obesity from 26.6% to 31%. ^{23 , 24} Intensive lifestyle and pharmacological intervention can significantly reduce the risk of progression to diabetes in patients with impaired FBGL or Iimpaired OGTT. ^{25 , 26}

This study aimed to investigate the prevalence, characteristics, and risk factors for prediabetes in Medan, Indonesia.

Our study demonstrated that the prevalence of individuals with prediabetes in Medan, Indonesia, using HbA1c, FBGL, and 2-hours postprandial OGTT were 28.1%, 50.6%, and 28.1%, respectively. The prevalence of prediabetes based on FBGL examinations in 33 provinces in Indonesia was 10%. ³¹ In this study, the prevalence of prediabetes using FBGL was one-fifth of that in the previous study. Another study found that the prevalence of prediabetes in Pontianak with an FBGL > 100 mg/dL was 76.5%. A significant increase in the prevalence of prediabetes has also been reported in the US, Europe, North America, the Caribbean, Africa, West Iran, and Malaysia. ^{32 , 33} The global prevalence of prediabetes using FBGL and 2-hours postprandial OGTT is estimated to increase to 6.5% and 10%, respectively, in 2045. ⁸

In this study, we found that most patients with prediabetes were 55-64 years old. Similar to the study by Andriani et al., the majority of prediabetic patients were > 50 years old. However, in this study, age was not significantly correlated with the incidence of prediabetes. A previous study found a significant relationship between age and incidence of prediabetes ( p=0.029). ²² Numerous additional factors that may impact the etiology of prediabetes are also associated with advanced age. Peripheral insulin resistance is increasing in tandem with these processes. with a poor diet, little exercise, or obesity. Hyperglycemia results if this process occurs in people who are at risk of developing prediabetes. The degree of environmental exposure and lifestyle choices have a significant impact on the rate and timing of development. ²²

The frequency of physical inactivity in the subjects diagnosed with prediabetes in this study was 37.1% ( p= 0.925). This contradicts the claim that a sedentary lifestyle influences the development of prediabetes and diabetes. Exercise helps to avoid obesity and increases insulin sensitivity. Compared to people who exercise, those who do not exercise may be more susceptible to developing prediabetes and diabetes. ³⁴ Our study showed that there was no correlation between physical activity, diet, hyperlipidemia, and prediabetes. This study is in accordance with previous studies that stated that physical activity, diet, and hypercholesterolemia had no relationship with the incidence of prediabetes. Although physical activity is known to be protective against the onset of type 2 diabetes, ³⁵ Redondo et al. ³⁶ did not find a correlation between prediabetes and noncompliance with the WHO physical activity guidelines. Similar results have been obtained in other investigations.

In this study, we found that most patients with prediabetes were female, overweight, or obese. This study is consistent with research conducted in Pontianak, showing that female and overweight or obesity are more prevalent among people with prediabetes. ²² However, in this study, we found that sex and BMI were not significantly correlated with the incidence of prediabetes.

Another study showed that sex and BMI were associated with prediabetes. Premenopausal women with prediabetes are prone to cardiometabolic risk factors and a threefold risk of obesity and central obesity. ³⁷ Our study showed that 82% of the respondents were women. Women of reproductive age are less susceptible to cardiovascular disease because of the protective effects of estrogen. Estrogen commonly reduces triglyceride and LDL-C circulating levels, while increasing HDL-C levels. However, some studies have mentioned the development of cardiovascular disease in women with lower blood glucose levels than in men. ^{38 – 40} The mean BMI in this study was 26.61 (95% CI 25.53-27.68). BMI is a risk factor for prediabetes. BMI is a simple anthropometric measure commonly used to measure general adiposity. ³⁷ Asian populations have more visceral fat than Caucasian populations do. This results in metabolic disorders, lipotoxicity, and insulin resistance. In addition, limited insulin secretory capacity and genetic predisposition play important roles in the development of insulin resistance. Several studies have reported that there is no relationship between BMI and the obesity paradox, and BMI acts as a simple indicator for evaluating the risk of blood glucose and lipid metabolism. ⁴¹ Maintaining a normal weight BMI is essential in the education of patients with prediabetes and is a concern for physicians. ⁴²

In this study, of 16 risk factors, only 3 risk factors have significant correlation with prediabetes in Medan ( p<0.05), namely HbA1c, IFG, and IGT. The American Diabetes Association (ADA) defines impaired fasting glucose (IFG) as having a fasting plasma glucose (FPG) level of 100–125 mg/dL, impaired glucose tolerance (IGT) as having a 2-hour postprandial glucose of 140–199 mg/dL, or elevated HbA1c (5.7%–6.4%) as having “prediabetes,” or intermediate hyperglycemia, and advises this population to make preventative efforts. Similar to the study by Barry et al., the majority of prediabetic participants in their sample showed elevated HbA1c (51%), IFG (67%), and IGT (32%) was significantly lower. ⁴³ This is a new finding that has never been published in this manner: women are significantly more likely than males to have elevated HbA1c levels.

Women are more likely than men to have increased HbA1c readings, which is a novel finding not previously documented in this manner. There was a substantial difference in the joint distribution of IGT, IFG, and elevated HbA1c values between men and women. Statistics suggest that the specific definition of prediabetes used can significantly impact the percentage of women and men who are classified as having prediabetes and are eligible for targeted lifestyle treatments to prevent diabetes. However, the exact reason for this observation is still unclear. ⁴⁰

Preventing T2DM provides significant public health benefits, including lower rates of complications. ⁴⁴ Implementing lifestyle counselling in clinical practice is feasible and cost-effective. ⁴⁵ Program-intensive lifestyle interventions from the DPP were to achieve and maintain a minimum weight loss of 7% and a physical activity of 150 min per week identical in intensity to brisk walking. The goal of physical activity was to approximate at least 700 kcal/week of physical activity. ⁴⁶ The 12-week intervention consisted of four nutrition visits and instructions on a high-carbohydrate diet (60% to 70% daily calories), high-fiber diet, and low-fat diet (<7% calories from saturated fat). The results showed 5% weight loss. ⁴⁴ In a study of participants at a high risk of diabetes, dietary fiber intake lowered postprandial blood glucose and insulin resistance. The recommended dietary fibre intake recommendation is 3.0 g or 1,000 kcal of total energy per day to prevent T2DM. ¹⁶ Holistic and integrated coordination is needed to assess the disease, including early detection in high-risk factor populations, targeted treatment, and intensive lifestyle modification.

This study found that The prevalence of prediabetes in the Medan group was 67.4%. 82% of the participants were female, and more than half were overweight or obese based on body mass index. Risk factors such as HbA1c, IFG, and IGT were significantly correlated with the incidence of prediabetes in Medan. Early detection is necessary to assess high-risk factors, targeted treatment, and intensive lifestyle modifications.