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Understanding Hypoglycemia

Simon Heller, MD
Sheffield, England, UK


On December 2, I will be speaking about hypoglycemia, including the pathophysiology, causes, and management, as part of the Worldwide Diabetes live webinar “Advancing Strategies in the Management of Type 2 Diabetes,” endorsed by Primary Care Diabetes Europe (PCDE).

Here’s a preview of what’s to come. 

Hypoglycemia, defined as a blood glucose level <3.9 mmol/L (70 mg/dL) is a major problem in patients with diabetes and a significant barrier to glycemic control in those requiring insulin (although it is also a problem in patients on oral drugs or even on diet alone). While more common in patients with Type 1 diabetes, it also occurs in those with Type 2 to varying degrees.1 One cross sectional study of more than 1,000 patients with type 2 diabetes found a 12% prevalence in patients managed with diet only; 16% in those using only oral diabetes drugs; and 30% in those using insulin.2 

Overall, studies suggest that the incidence of hypoglycemia in patients with type 2 diabetes is about a third that of those with type 1. It is all individual, however. Some patients may have very frequent events, some severe, while most may experience only one or two events over their lifetime. 

However, it appears we may be underestimating the prevalence of hypoglycemia in our patients. This comes from the global Hypoglycemia Awareness Tool (HAT) study that was a 6‐month retrospective and 4‐week prospective study using self‐assessment questionnaire and patient diaries of 27,585 patients with type 1 (n=8,022) or type 2 (n=19,563) diabetes treated with insulin for more than 12 months. It found hypoglycemia rates about 3 times higher than most population-based studies.3 A North American community study reported similar results, with about 3.5 severe events a year in type 1 adults and 2 in type 2 diabetes, affecting 50% and 33% respectively.4

Hypoglycemia is not a benign event. Not only is it disruptive to daily life, but the more episodes patients experience the more they are likely to experience. It can lead to vehicular accidents, cause falls and injuries, and, in severe cases lead to hospitalization and death.5

There is also an association between severe hypoglycemic events and cognitive impairment and dementia.6 In addition, recent work finds that hypoglycemia contributes to an increased risk of cardiovascular events. In fact, there is some thought that this may be why trials of intensive insulin treatment for type 2 diabetes didn’t show the expected reduction in macrovascular events and, in at least one trial, demonstrated an increased risk of mortality.7,8

And yet clinicians often underestimate the impact of hypoglycemia on their patients, pushing for insulin intensification without fully considering the risk of hypoglycemia. As one man with type 1 diabetes wrote in a letter to The New York Times: “Most doctors cannot appreciate how greatly [hypoglycemia] affects daily life.”9

Providing patient-centered care means understanding the risk and implications of hypoglycemia for patients and structuring the treatment program around those issues. 

What questions do you have? Are there any barriers you face in prescribing these drugs? Do you start them in hospitalized patients given the rapid onset of effect? Comment below.

Register for Worldwide Diabetes Virtual Webinar

The virtual webinar is sponsored by the Worldwide Initiative for Diabetes Education and supported by an educational grant from Novo Nordisk A/S.



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1Akram K, Pedersen-Bjergaard U, Borch-Johnsen K, et al. Frequency and risk factors of severe hypoglycemia in insulin-treated type 2 diabetes: a literature survey. J Diabetes Complications. 2006;20(6):402-408.
2 Akram K, Pedersen-Bjergaard U, Borch-Johnsen K, Thorsteinsson B. Frequency and risk factors of severe hypoglycemia in insulin-treated type 2 diabetes: a literature survey. J Diabetes Complications. 2006;20(6):402-8.
3 Khunti K, Alsifri S, Aronson R, et al. Rates and predictors of hypoglycaemia in 27,585 people from 24 countries with insulin-treated type 1 and type 2 diabetes: the global HAT study. Diabetes Obes Metab. 2016;18(9):907-915. doi:10.1111/dom.12689.
5 Ortiz MR. Hypoglycemia in Diabetes. Nurs Clin North Am. 2017;52(4):565-574.
6 Rhee SY. Hypoglycemia and Dementia. Endocrinol Metab (Seoul). 2017 Jun;32(2):195-199. doi: 10.3803/EnM.2017.32.2.195. PMID: 28685510; PMCID: PMC5503864.
7 Patel A, MacMahon S, Chalmers J, et al. Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes. N Engl J Med. 2008;358:2560-2572.
8 Gerstein HC, Miller ME, Byington RP, et al. Effects of intensive glucose lowering in type 2 diabetes. N Engl J Med. 2008; 358:2545-2559, 2008
9 Meyer J. Letter to the editor. The New York Times. January 14, 2015.