An evaluation of recurrent hypoglycemia across Chicago, Illinois Clare E. O'Connor a , Elissa H. Oh b , Kathryn L. Jackson d , Daniel J. Finn b , Marc B. Rosenman c , Mark E. Molitch a , Abel Kho d , Amisha Wallia a,b, ⁎ a Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago IL, USA b Center for Health Services and Outcomes Research, Institute for Public Health and Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA c Ann & Robert H. Lurie Children's Hospital of Chicago and Institute of Public Health, Feinberg School of Medicine, Chicago, IL, USA d Institute of Public Health, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA abstract article info Article history: Received 13 February 2020 Received in revised form 15 July 2020 Accepted 15 July 2020 Available online xxxx Keywords: Hypoglycemia Fragmentation of care Diabetes mellitus Aims: Recurrent hypoglycemia is understudied. This study evaluates recurrent hypoglycemia, fragmentation of care and mortality in a large urban center. Methods: The Chicago HealthLNK Data Repository (CHDR), a de-identified electronic health record data set from institutions across Chicago, identified 9741 patients with diabetes (DM) who had hypoglycemia (emergency de- partment (ED) or inpatient admission (IA)) from 2006 to 2012. Recurrence was defined as more than one hypo- glycemia encounter, and fragmentation of health care was defined as an ED visit or IA for hypoglycemia at N1 site. Results: 187,644 patients were identified with DM; of 9741 patients with hypoglycemia, 2857 (29.3%) had recur- rence. Patients with ≥4 hypoglycemic encounters (n = 1035) represented 10.6%, but accounted for 40.3% hypo- glycemic encounters. Of 2857 patients with recurrence, 304 patients (10.6%) had fragmented care. In those with high hypoglycemic encounters (≥4), 22% (N = 226) had ≥10 encounters; race and insurance status differences were associated with number of hypoglycemic encounters. Having hypoglycemia was associated with increased mortality compared to no hypoglycemia (n = 2696, 27.7% vs n = 20,188, 11.4%; p b 0.00001 by chi-square). Conclusion: A small subset of patients with hypoglycemia accounted for a large subset of hypoglycemia encoun- ters. Targeted interventions in this high-risk, high mortality group are needed. © 2020 Published by Elsevier Inc. 1. Introduction Hypoglycemia is increasingly being recognized as an important acute complication of diabetes and is a barrier to achieving optimal dia- betes outcomes. 1,2 Hypoglycemia has been linked to increases in mor- tality and cardiovascular disease, 3–6 and hospital admission rates for hypoglycemia now exceed those for hyperglycemia among older adults. 7 Several studies have identified various risk factors for hypogly- cemia, such as advanced age, cognitive dysfunction, nephropathy/renal failure, previous hypoglycemia, female gender, polypharmacy, black race, poor glycemic control, or any insulin use, among others. 8–11 There is evidence that it is often a minority of patients that account for the majority of hypoglycemia requiring acute care. 10 However, little is known about those with recurrent hypoglycemia and care delivery, such as across health systems. There are limited studies on the incidence of recurrent hypoglyce- mia. A study looking at one tertiary care hospital found that of the 233 patients treated for a severe hypoglycemia encounter, 31.8% had recurrent hypoglycemia after hospital admission. 12 However, to our knowledge no studies have evaluated incidence of recurrent hypoglyce- mia, distribution in number of hypoglycemia encounters, and fragmen- tation of care at the patient level across several hospital systems. Single center studies may underestimate the rate of recurrent hypoglycemia if there is care fragmentation (patient that receives health care at more than one institution). Health care fragmentation has independently been associated with an increase in hospital admissions and higher utilization of health care. 13 Our group has previously studied another acute complication of dia- betes, recurrent diabetic ketoacidosis (DKA) and fragmentation of care in the Chicago area and found that a small subset of patients (5.8% of the total DKA group) had four or more episodes of DKA, but made up 26.2% of hospitalizations and were three times more likely to have fragmented care. 14 This study evaluated recurrent hypoglycemia (for the purposes of this study defined as an Emergency Department (ED) visit or inpatient admission for the diagnosis of hypoglycemia), fragmentation of care, and mortality in a large cohort of patients with diabetes mellitus (DM) across multiple health care systems in Chicago. Our goal was to identify and describe those with single, and recurrent hypoglycemia as they rep- resent a very high risk, high morbidity group. 15 Journal of Diabetes and Its Complications xxx (xxxx) xxx ⁎ Corresponding author at: 645 North Michigan Avenue, Suite 530, Chicago, IL 60611, USA. E-mail address: a-wallia@northwestern.edu (A. Wallia). JDC-107685; No of Pages 4 https://doi.org/10.1016/j.jdiacomp.2020.107685 1056-8727/© 2020 Published by Elsevier Inc. Contents lists available at ScienceDirect Journal of Diabetes and Its Complications journal homepage: WWW.JDCJOURNAL.COM Please cite this article as: C.E. O'Connor, E.H. Oh, K.L. Jackson, et al., An evaluation of recurrent hypoglycemia across Chicago, Illinois, Journal of Diabetes and Its Complications, https://doi.org/10.1016/j.jdiacomp.2020.107685