Spotlight on hypoglycemia

The risks and consequences of hypoglycemia were described by several studies published recently.

First, a meta-analysis, published by BMJ on July 30, found that type 2 diabetes patients who had episodes of severe hypoglycemia were much more likely to have cardiovascular disease (relative risk 2.05, 95% CI, 1.74 to 2.42; P<0.001). The authors, who analyzed six studies with more than 900,000 patients, calculated that the excess fraction of cardiovascular disease incidence attributable to severe hypoglycemia was 1.56% (95% CI, 1.32% to 1.81%; P<0.001). The result was significant enough after adjustment that it is unlikely to be explained by comorbid severe illness, the authors concluded, recommending solutions such as individualized therapy targets, agents unlikely to cause hypoglycemia (like metformin), and patient self-monitoring.

In a prospective, population-based study of 783 older adults with diabetes, hypoglycemic events were found to be associated with a doubling of risk of developing dementia. According to results published by in the July 22 JAMA Internal Medicine (and online-first June 10), 7.8% of the study population (or 61 patients) had a hypoglycemic event requiring hospitalization, and 34.4% of that group developed dementia, compared to 17.6% of non-hypoglycemic patients (hazard ratio [HR], 2.1; 95% CI, 1.0 to 4.4, P<0.001). Patients who developed dementia also had higher risk of subsequent hypoglycemia (14.2% vs. 6.3%, P<0.001; HR, 3.1; 95% CI, 1.5-6.6). The results provide evidence of a reciprocal association between hypoglycemia and dementia, and should encourage clinicians to consider cognitive function in the clinical management of older patients with diabetes, the study authors concluded.

Finally, a survey of type 2 diabetes patients in a large health care system found that severe hypoglycemia is common, regardless of patients' hemoglobin A1c (HbA1c) levels. Of the 9,094 Californian survey respondents (mean age 59.5), 10.8% reported experiencing severe hypoglycemia in the previous year. Patients with the lowest and highest HbA1cs reported more hypoglycemia than those in the middle, according to results published online by Diabetes Care July 30. With an HbA1c of 7–7.9% as the reference, the adjusted relative risk of hypoglycemia was 1.25 (95% CI 0.99–1.57) for patients with HbA1c <6%, 1.01 (0.87–1.18) for 6–6.9%, 0.99 (0.82–1.20) for 8–8.9%, and 1.16 (0.97–1.38) for ≥9%. Age, diabetes duration, and category of diabetes medication did not significantly modify the association. The study's finding that self-reported severe hypoglycemia occurs just as frequently among patients with poor glycemic control as those with near-normal glycemia counters conventional wisdom, the researchers noted. It may highlight the risks of intensifying therapy in patients who have not already responded well, and shows that concerns about hypoglycemia should not be limited to patients with low HbA1cs.