Fasting-Evoked En Route Hypoglycemia in Diabetes (FEEHD): From Guidelines to Clinical Practice

Background: Lipid profiles have been used for the purposes of health screening and monitoring of the effects of lipid-lowering medications, especially in patients with diabetes who are prone to hyperlipidemia. Fasting for lipid profiles has been the norm for the past decades. This long-lasting tradition poses a risk of hypoglycemia, especially in patients with diabetes. Objective: Our aim is to review the overlooked occurrence of hypoglycemia in patients who fast for laboratory tests, especially lipid profile tests, and commute to the laboratory facility while fasting; a condition we titled “Fasting-Evoked En route Hypoglycemia in Diabetes patients” or “FEEHD”. We also review its prevalence and clinical impact on patients with diabetes. Methods: We undertook an extensive literature search using search engines such as PubMed and Google Scholar. We used the following keywords for the search: Fasting, Non-fasting; Hypoglycemia; Hypoglycemic Agents; Laboratory Tests; Glucose, Hypoglycemia, Lipid Profiles, FEEHD. Results: Our literature review has shown that the prevalence of FEEHD is alarmingly high (17-21% of patients at risk). This form of hypoglycemia is under recognized in the clinical practice despite its frequent occurrence. Recent changes in various international guidelines have uniformly endorsed the utilization of non-fasting lipid profiles as the new standard for obtaining lipid profiles with the exception of certain conditions. Multiple studies showed the efficacy of non-fasting lipid tests in comparison to fasting lipid tests, in routine clinical practice. Conclusion: We hope to increase awareness among clinicians about this overlooked and potentially harmful form of hypoglycemia in patients with diabetes, which can be easily avoided. We also hope to call upon clinicians to consider changing the habit of ordering lipid profiles in the fasting state, which has been recently shown to be largely unnecessary in routine clinical settings, with few exceptions in selected cases.