Vital Signs, QT Prolongation, and Newly Diagnosed Cardiovascular Disease During Severe Hypoglycemia in Type 1 and Type 2 Diabetic Patients

Abstract

OBJECTIVETo assess vital signs, QT intervals, and newly diagnosed cardiovascular disease during severe hypoglycemia in diabetic patients. RESEARCH DESIGN AND METHODSFrom January 2006 to March 2012, we conducted a retrospective cohort study to assess type 1 and type 2 diabetic patients with severe hypoglycemia at a national center in Japan. Severe hypoglycemia was defined as the presence of any hypoglycemic symptoms that could not be resolved by the patients themselves in prehospital settings. RESULTSA total of 59,602 cases that visited the emergency room by ambulance were screened, and 414 cases of severe hypoglycemia were analyzed. The median (interquartile range) blood glucose levels were not significantly different between the type 1 diabetes mellitus (T1DM) (n = 88) and type 2 diabetes mellitus (T2DM) (n = 326) groups (32 [24-42] vs. 31 [24-39] mg/dL, P = 0.59). During severe hypoglycemia, the incidences of severe hypertension ( ‡180/120 mmHg), hypokalemia (<3.5 mEq/L), and QT prolongation were 19.8 and 38.8% (P = 0.001), 42.4 and 36.3% (P = 0.30), and 50.0 and 59.9% (P = 0.29) in the T1DM and T2DM groups, respectively. Newly diagnosed cardiovascular disease during severe hypoglycemia and death were only observed in the T2DM group (1.5 and 1.8%, respectively). Blood glucose levels between the deceased and surviving patients in the T2DM group were significantly different (18 [14-33] vs. 31 [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] mg/dL, P = 0.02). CONCLUSIONST1DM and T2DM patients with severe hypoglycemia experienced many critical problems that could lead to cardiovascular disease, fatal arrhythmia, and death.

Hypoglycemia and Risk of Cardiovascular Disease and All-Cause Mortality in Insulin-Treated People With Type 1 and Type 2 Diabetes: A Cohort Study

“…Since the ACCORD and VADT results were published, attempts have been made to assess whether a relationship exists between hypoglycemia and CV risk or mortality, but only recently has a consensus begun to emerge suggesting that there is a link between the two (6,8,9). Several potential mechanisms linking hypoglycemia and CV risk have been proposed, including QT prolongation, hemodynamic changes arising from catecholamine release, inflammation, and endothelial dysfunction (23)(24)(25). Although real, these effects are more likely to explain a transient increase in CV risk during the acute phase of hypoglycemia rather than the longer-term relationship observed in the current study.…”

Hypoglycemia and Cardiovascular Risk: Is There a Major Link?

“…A surrogate measure of myocardial perfusion during hypoglycemia in young adults with and without type 1 diabetes has recorded lower values in the group with diabetes (23). How often severe hypoglycemia may cause myocardial infarction is unknown, as only a few anecdotal cases have been reported, while a large retrospective Japanese study of 414 subjects presenting with severe hypoglycemia revealed newly diagnosed vascular disease in five patients (with only 1 case of myocardial infarction and 4 cases of cerebrovascular disease) (24).…”

“…This has been demonstrated in both type 1 and type 2 diabetes (24,(29)(30)(31). QT prolongation is a strong risk factor for severe ventricular arrhythmia and sudden death (32) and has been suggested as an explanation for the "dead in bed" syndrome of patients with type 1 diabetes (29).…”

High risk of renal dysfunction in patients with fulminant type 1 diabetes

“…Estimated GFR was calculated using the following formula10: $\text{estimated GFR (mL/min/1.73}{\mathrm{normalm}}^{2}false)=194\times \text{(serum creatinine}\text{level,}{\text{mg/dL)}}^{-1.094}\times \text{(age,}{\text{years)}}^{-0.287}false(\times 0.739\text{if the patient}\text{was a woman}false)$. A severe hypoglycemic episode was defined as the presence of any hypoglycemic symptoms that could not be resolved by the patients outside a hospital setting, and that required medical assistance after visiting the emergency room by ambulance11. Cardiovascular disease included angina, myocardial infarction, stroke and transient ischemic attack.…”