Objective: There is no standardized defined threshold for outpatient critical action value (CAV) hypoglycemia and a scarcity of literature on provider responses to it. The aim of this study was to characterize patient demographics of, provider/patient responses to, and clinical sequelae of CAV hypoglycemia.

Methods: This was a retrospective EMR-based cohort study of all ambulatory patients with a serum glucose <50 mg/dL measured at the clinical laboratories of Johns Hopkins Hospital and Johns Hopkins Bayview Medical Center between April 1, 2013 and January 31, 2017. Manual chart review was conducted using an electronic questionnaire.

Results: Two hundred nine CAV hypoglycemic episodes from 106 unique patients were identified. The median (IQR) hypoglycemic BG value was 43 (37.0, 47.0) mg/dL, and the median time from BG specimen collection to result was 158.0 min. The majority (72.2%) of patients had diabetes mellitus. The next 3 most common comorbidities were CHF (29.2%), HIV (19.6%), and ESRD (8.6%). The median age was 58 yrs and the majority (67.0%) were black; there was roughly equal gender distribution (53.6% male). Providers contacted patients in 128 (61.2%) of these episodes, and most commonly no hypoglycemic etiology (63.3%) and no signs or symptoms of hypoglycemia (80.5%) were documented. The most common documented symptoms were weakness/fatigue (32.0%), dizziness (16.0%), and tremor (12.0%). Only 4 serious adverse events were found, 3 of which had a related ED visit within 24 hrs of CAV, 1 of which involved loss of consciousness, and 2 of which involved glucagon administration.

Conclusion: Though CAV hypoglycemia tended to occur in individuals over 50 with common comorbidities and without documented hypoglycemic signs/symptoms, providers inconsistently reached out to patients and there were few serious adverse events. Further research is needed to identify optimal CAV glucose thresholds and responses, especially considering the delay between lab draw and provider/patient communication.


A. Ashok: None. M.S. Abusamaan: None. N. Mathioudakis: None.


National Institute of Diabetes and Digestive and Kidney Diseases (1K23DK111986-01)

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