A critical review of the literature on fear of hypoglycemia in diabetes: Implications for diabetes management and patient education

Abstract

Objective

In many individuals with diabetes, the unpleasant symptoms and negative consequences associated with hypoglycemia may result in significant anxiety or even a fear of hypoglycemia (FoH). This fear may have significant clinical implications for diabetes management. The aim of this review is to integrate existing research on FoH (its measurement, predictors, correlates, impact and treatment) and discuss its implications for diabetes management and patient education.

Methods

A literature search was conducted using Medline and Embase. The search was limited to journal articles published in English from 1985 to 2007 inclusive. Three hundred and one abstracts were reviewed and 273 were rejected on the basis of non-relevance. In addition to the 28 papers included, six additional papers were identified by further searches and were added to this review.

Results

FoH appears to be a widespread phenomenon. It is measured primarily through the use of a specific scale, the Hypoglycemic Fear Survey (HFS). There are a number of factors that relate to whether an individual is likely to develop FoH including whether there is a history of hypoglycemia in an individual, length of time since first insulin treatment, and a higher level of variability in blood glucose level. FoH has been linked to both state and trait anxiety although the relationship is complex.

Conclusions

There is evidence that FoH may have a significant negative impact on diabetes management, metabolic control and subsequent health outcomes. There is evidence that blood glucose (BG) awareness training and CBT can reduce levels of fear and improve disease management. More research is needed on how FoH arises and the individual variables which predict its development. In addition, well designed research is required to better understand the behavioral and medical impact of FoH, and interventions to reduce it.

Practice implications

There is some evidence to suggest that interventions including BG awareness training and cognitive behavioral therapy can reduce levels of fear and improve disease management. While many aspects of FoH require further well-designed research, it is evident that this phenomenon can have a major impact on diabetes management and needs to be specifically addressed in patient education programs.

Introduction

The maintenance of normalised blood glucose (BG) levels leads to a reduction in the onset and advancement of diabetic complications in type 1 and type 2 diabetes [1], [2]. However, this is a difficult task to accomplish as the maintenance of normalised BG levels also increases the incidence of episodes of hypoglycemia [1]. If not for the problem of hypoglycemia, it would be much easier for people with diabetes to have normal glycated hemoglobin (HbA1c) values throughout their life [1], [3].

Hypoglycemia is the most common adverse event associated with insulin treatment in type 1 and type 2 diabetes. It can occur suddenly and is characterized by unpleasant physical and psychological symptoms such as shaking, sweating, drowsiness, nausea, poor motor coordination, mental confusion, negative mood, and unconsciousness.

Some authors point to the difficulty in distinguishing between the symptoms of hypoglycemia and the symptoms of anxiety which can complicate the delivery of psychological interventions [4]. Whilst some of the symptoms of anxiety mirror those of hypoglycemia, such as shaking, sweating, nausea, and mental confusion, there are many symptoms that are do not cross over. For example, hypoglycemia does not cause a person to have diarrhea, dry mouth, tightness or pain in the chest, muscle tension, or frequent urination.

Hypoglycemia is a major limiting factor in the glycemic management of type 1 and type 2 diabetes mellitus [1], [3]. Intensifying insulin treatment to lower HbA1c leads to an increase in the number of hypoglycemic events. The Diabetes Complications and Controls Trial (DCCT) found that strict glycemic control resulted in a three-fold increase in the number of hypoglycemic events in type 1 diabetes [1]. Similarly, in the UK Prospective Diabetes Study (UKPDS), the maintenance of tight glycemic control led to a significant increase in the incidence of hypoglycemia in individuals with insulin treated type 2 diabetes [2].

Severe hypoglycemia can result in physical injury, automobile accidents, and even death. In a preliminary report from the DCCT, 817 patients with type 1 diabetes were followed for a mean of 21 months. There were 714 episodes of severe hypoglycemia in a subset 216 of these patients. Over one-half of the episodes occurred at night, and over three-quarters in patients receiving intensive insulin therapy [1]. Hypoglycemia is somewhat less common in type 2 diabetes, because deficits in glucagon and epinephrine secretion are much less prominent and strict glycemic control (predisposing patients to low BG concentrations) is much more difficult to achieve.

Patients actively trying to manage their diabetes are balancing the need to avoid these acute effects and the long-term complications of hyperglycemia, and immediate consequences are often much more salient to patients than the possibility of more vague future health problems. This may especially be the case if they have first hand experience of the immediate negative consequences of an acute episode of hypoglycemia.

Given the unpleasant aspects of hypoglycemia and the potentially life threatening nature of severe hypoglycemia, it is not surprising that many people with type 1 diabetes or insulin treated type 2 diabetes have a significant fear of developing hypoglycemia. FoH appears to be particularly prevalent in patients who have had severe hypoglycemic episodes, such as ones that have involved loss of consciousness. This makes intuitive sense, as the more unpleasant or traumatic the event, the more likely someone is to develop anxiety about a repeat episode. Steps taken to avoid this situation may then be reinforced as they are associated with a reduction in the person's anxiety.

This avoidance may have significant clinical implications for diabetes management. In order to avoid the aversive symptoms of past hypoglycemia episodes, patients who have FoH may engage in ‘over-compensatory behaviors’. This may include taking less insulin than they need or overeating, in order to avoid hypoglycemia. This type of coping response may result in poor metabolic control and increase the risk of serious health consequences associated with diabetes. People with diabetes with a history of past severe hypoglycemic episodes (the ones most adverse to FoH) are often the patients with more severe diabetes and for whom appropriate disease management is especially critical.

The aim of this review is to integrate a wide range of research on FoH. This includes studies that have attempted to measure the phenomenon, studies investigating predictors and correlates of FoH, and the impact of FoH on behavior, and studies exploring possible interventions to treat FoH. Finally, the findings will be integrated and implications for patient education and disease management will be discussed.