Diabetes is a chronic disease that is increasing in prevalence worldwide. Glycemic control is the main treatment for patients with diabetes, and many studies provide evidence that glycemic control prevents or delays the development of microvascular complications of diabetes [1,2,3]. However, the occurrence or fear of hypoglycemia is a barrier to achieving glycemic control. When patients encounter hypoglycemia, they are less likely to comply with drug therapy and may have additional psychiatric problems in their daily lives [4,5]. Moreover, severe hypoglycemia increases cardiovascular mortality in old age or in the presence of comorbidities [6,7,8]. In the Action to Control Cardiovascular Risk in Diabetes Study (ACCORD) trial, the intensive therapy group (glycosylated hemoglobin [HbA1c] <6.0%) experienced higher mortality than did the standard therapy group (HbA1c, 7.0% to 7.9%), possibly due to more severe or frequent hypoglycemic events in the intensive therapy group [9]. Following the publication of these data, recent guidelines address concerns about hypoglycemia, especially in patients with comorbidities, and emphasize that therapy should be tailored to the individual [10].

For the prevention of hypoglycemia, the 2016 American Diabetes Association guidelines recommended a chronic care model (CCM), which would improve the clinical outcome and adherence to therapy, involving a team approach (doctors, nurses, dieticians, and social workers) [10]. In addition, repeated and frequent diabetes education must be undertaken regarding self-management to improve clinical outcomes and quality of life. This can be conducted through mass media, including television, radio, and newspaper [11,12,13]. However, there is a lack of data regarding the insight of diabetic patients into hypoglycemia in a real-world setting. Therefore, in this study, we investigated the understanding by diabetes patients of hypoglycemia, the behavior they use to avoid hypoglycemia, and their fear of hypoglycemia, by using a questionnaire.

In this study, about 60% of participants reported experiencing hypoglycemia, but many subjects could not identify symptoms of hypoglycemia or what they should do after detecting them. Participants who had poor glucose control (HbA1c ≥8%), were treated with insulin, and had visited the ER yielded higher scores for both hypoglycemia avoidance behavior and fear of hypoglycemia. However, many participants did not report hypoglycemic events to their doctor before they were asked.

Hypoglycemia is defined as a blood glucose of <70 mg/dL, accompanied by sweating, dizziness, and other symptoms [16,17]. Mild hypoglycemia can usually be self-treated, whereas severe hypoglycemia is defined by a requirement for external assistance [10,16]. Hypoglycemia is especially common in older patients or in those with comorbidities, in whom it affects compliance with medical therapy, lifestyle, and mortality. Recent guidelines emphasize that therapeutic regimens should be tailored to the needs of specific patients, rather than being aimed purely at achieving glycemic control within a near-normal range [10]. This is because hypoglycemia can cause very serious consequences, sometimes resulting in the death of patients with cardiovascular disease [6,7,8,9]. The incidence of hypoglycemia varies according to the type of diabetes, therapeutic regimen, and age of diabetic patients. In a review of 46 studies (n=532,542) of hypoglycemia, the prevalence of hypoglycemia was 45% for mild/moderate events and 6% for severe events. The incidences of mild/moderate and severe hypoglycemic episodes per person-year were 19 (95% CI, 0.00 to 51.08) and 0.80 (95% CI, 0.00 to 2.15), respectively [18]. In this study, about 60% of participants reported experiencing hypoglycemia, but many participants could not identify the symptoms of hypoglycemia or what they should do after detecting them. In addition, a third of participants could not define hypoglycemia at the time of the study.

Diabetes self-management education (DSME) is an important element of diabetes care, in particular in the prevention or delay of the development of diabetic complications [13,19,20,21,22]. Patients should learn about their optimal daily care and how to act under various circumstances. For effective education, it is important to know how well-informed each patient is. In the present survey, only 19.4% of patients could define hypoglycemia correctly (<70 mg/dL), and from the list of 12 correct hypoglycemic symptoms, participants could identify only a mean of 3.3. Most patients did not know that symptoms such as headache, perspiration, and seizure can occur during hypoglycemia. Although many participants chose candy as an immediate treatment for hypoglycemia, others chose chocolate, rice, or nuts. In addition, many consumed candy without checking their blood glucose beforehand. Finally, only 10.9% of patients had kept their medical alert cards. Even though the groups of patients who received hypoglycemia education were segregated, the results were not much different. The educated group showed better results in some of questions. However, they had a lower proportion of correct answers in these questions, Moreover, they showed no significant difference or worse results compared to the uneducated group in other questions. These results show that many patients with diabetes are not well-informed regarding hypoglycemia, even though they have received some education.

The occurrence of hypoglycemia limits daily activities and lowers quality of life [23,24,25,26,27]. According to surveys of the fear associated with hypoglycemia in type 1 diabetes mellitus, patients prefer to try to keep their blood glucose higher than recommended, limit activities such as visiting friends, display emotional deficits, such as low confidence, and can also suffer psychiatric problems, such as panic attack or agoraphobia [28]. In addition, patients who experienced hypoglycemia had poorer health and were more likely to be depressed than those who did not experience hypoglycemic events [4].

Chronic untreated hypoglycemia can result in cerebral maladaptation, causing impaired awareness of hypoglycemia, which is termed “hypoglycemic unawareness” [29], and increases the fear of hypoglycemia [30]. Some studies reported a positive correlation between this fear and HbA1c, but this result was inconsistent [25,31]. In addition, it was shown that a single episode of hypoglycemia can trigger anxiety, resulting in the development of avoidance behavior aimed at maintaining higher than recommended blood glucose levels [24,31,32]. Similar to the results of other studies, the group using insulin and those patients with an HbA1c of >8.0% had significantly higher scores for avoidance behavior and worry about hypoglycemia. In addition, the group that had already experienced visits to the ER due to hypoglycemia tended to have higher avoidance behavior and fear scores than the group without ER visits due to hypoglycemia.

Patients who worry about hypoglycemia tend to eat more to avoid it, and, as their HbA1c increases, their doctors may add additional medication to control hyperglycemia without talking about hypoglycemia. Therefore, if communication is insufficient to identify this problem, patients may enter a vicious cycle of overmedication. Recently, the CCM was introduced, which is a well-rounded approach to restructuring medical care that involves partnerships between health systems and communities in U.S. primary care settings [10]. For this, physicians are trained to deliver evidence-based care, support decision making, and offer DSME through personal or group sessions. The design of the delivery system incorporates diabetes days, which facilitates communication between patients and diabetes educators. In this patient-centered approach, patients and diabetes educators create patient records collaboratively and can discuss treatment in more detail. Studies using CCM showed that it improved not only metabolic parameters, such as HbA1c and high density lipoprotein, but also psychosocial parameters, such as diabetes knowledge and empowerment scores [33,34,35].

Surprisingly, Ostenson et al. [36] reported that almost half of patients rarely or never informed their general practitioner or specialist of a hypoglycemic event, despite over half of them had experienced such events. Similarly, in the present study, only half of the patients informed their physician of a hypoglycemic event before they were asked. These results show that improved communication between physicians and patients is important to provide better treatment.

This study has a few limitations. Data were collected using questionnaires, the accuracy of which depended on the memory of the patients. Patient recall is typically subjective, and here it did not correlate with the extent of the education provided by the respective care teams. The participants in the survey had a higher proportion of insulin treatment than general patients, so the possibility of selection bias must be considered. However, our data are made more relevant because they identify the level of patient knowledge regarding hypoglycemia in a real-world clinical care situation. Taken together, our results indicate that many patients have a lower degree of knowledge about hypoglycemia than was expected, and a greater level of worry. Furthermore, many patients did not tell their doctor about hypoglycemic events that they had experienced. Therefore, to ensure optimal treatment of diabetes and fewer hypoglycemic events, an improved system of communication between patients and their care teams should be established, including a better education program regarding diabetes self-management.