Objectives: There is very limited information about glycemic control after discharge from the ICU. The aims of this study were to evaluate the prevalence of hypoglycemia in ICU survivors with type-2 diabetes and determine whether hypoglycemia is associated with cardiac arrhythmias.
Design: Prospective, observational, two-center study. Participants underwent up to 5 days of simultaneous blinded continuous interstitial glucose monitoring and ambulatory 12-lead electrocardiogram monitoring immediately after ICU discharge during ward-based care. Frequency of arrhythmias, heart rate variability, and cardiac repolarization markers were compared between hypoglycemia (interstitial glucose ≤ 3.5 mmol/L) and euglycemia (5-10 mmol/L) matched for time of day.
Setting: Mixed medical-surgical ICUs in two geographically distinct university-affiliated hospitals.
Patients: Patients with type-2 diabetes who were discharged from ICU after greater than or equal to 24 hours with greater than or equal to one organ failure and were prescribed subcutaneous insulin were eligible.
Measurements and Main Results: Thirty-one participants (mean ± sd, age 65 ± 13 yr, glycated hemoglobin 64 ± 22 mmol/mol) were monitored for 101 ± 32 hours post-ICU (total 3,117 hr). Hypoglycemia occurred in 12 participants (39%; 95% CI, 22-56%) and was predominantly nocturnal (40/51 hr) and asymptomatic (25/29 episodes). Participants experiencing hypoglycemia had 2.4 ± 0.7 discrete episodes lasting 45 minutes (interquartile range, 25-140 min). Glucose nadir was less than or equal to 2.2 mmol/L in 34% of episodes. The longest episode of nocturnal hypoglycemia was 585 minutes with glucose nadir less than 2.2 mmol/L. Simultaneous electrocardiogram and continuous interstitial glucose monitoring recordings were obtained during 44 hours of hypoglycemia and 991 hours of euglycemia. Hypoglycemia was associated with greater risk of bradycardia but did not affect atrial or ventricular ectopics, heart rate variability, or cardiac repolarization.
Conclusions: In ICU survivors with insulin-treated type-2 diabetes, hypoglycemia occurs frequently and is predominantly nocturnal, asymptomatic, and prolonged.
Competing Interests: Dr. Ali Abdelhamid’s institution received funding from the Intensive Care Foundation and Baxter; she disclosed that Welch Allyn Australia loaned Holter recorders for the conduct of the study but was not involved in the design, conduct, analysis, or reporting of the study; and she was supported by a Royal Adelaide Hospital A. R. Clarkson Scholarship. Dr. Bernjak received support for article research from the Intensive Care Foundation. Drs. Bernjak’s, Summers’, and Heller’s institutions received funding from an Intensive Care Foundation grant, administered by Melbourne Health. Dr. Phillips was supported by a Royal Adelaide Hospital Early Career Fellowship. Dr. Heller received funding from NovoNordisk, Eli Lilly, Zealand Pharma, Sanofi, Aventis, and Astra Zeneca. Dr. Deane is supported by a National Health and Medical Research Council Career Development Fellowship. The remaining authors have disclosed that they do not have any potential conflicts of interest.
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