title: Incidence and risk factors for severe and symptomatic hypoglycemia in type 1 diabetes. Results of the HYPOS-1 study.
abstract: OBJECTIVE
  Hypoglycemia is common in type 1 diabetes mellitus (T1DM). We aimed to update the incidence of severe and symptomatic hypoglycemia and investigate several correlated factors.
  
  
  METHODS
  In this multicenter, observational retrospective study, the data of 206 T1DM patients from a sample of 2,229 consecutive patients seen at 18 diabetes clinics were analyzed. Sociodemographic and clinical characteristics, severe hypoglycemia in the past 12 months, and symptomatic hypoglycemia in the past 4 weeks were recorded with a self-report questionnaire and a clinical form during a routine visit. Poisson multivariate models were applied.
  
  
  RESULTS
  A minority of patients accounted for the majority of both severe and symptomatic episodes. The incidence rate (IR) of severe hypoglycemia was 0.49 (0.40-0.60) events/person-years. The incidence rate ratio (IRR) was higher in patients with previous severe hypoglycemia (3.71; 2.28-6.04), neuropathy (4.16; 2.14-8.05), long duration (>20 years, 2.96; 1.60-5.45), and on polypharmacy (1.24; 1.13-1.36), but it was lower when a complication was present. The IR of symptomatic hypoglycemia was 53.3 events/person-years, with an IRR significantly higher among women or patients with better education, or shorter duration or on pumps. The IRR was lower in patients with higher BMI or neuropathy or aged more than 50 years.
  
  
  CONCLUSIONS
  Fewer than 20 % of T1DM patients are free from hypoglycemia, with one in six having experienced at least one severe episode in the last year. The distribution is uneven, with a tendency of episodes to cluster in some patients. Severe and symptomatic episodes have different correlates and reflect different conditions.
authors: Metabolism and Diabetes Unit, ASL TO5, Via De Maria, 1, 10023, Chieri, TO, Italy. giordaca@tin.it.
authors: Carlo B
authors: CB
authors: Giorda
authors: Departmental Service of Diabetology and Metabolic Diseases, ASL TO3, Pinerolo, TO, Italy.
authors: Alessandro
authors: A
authors: Ozzello
authors: Department of Clinical and Experimental Medicine, Second University of Naples, Naples, Italy.
authors: Sandro
authors: S
authors: Gentile
authors: Metabolism and Diabetes Unit Hospital St. Martin, Genoa, Italy.
authors: Alberto
authors: A
authors: Aglialoro
authors: Metabolism and Diabetes Unit, ASL TO4, Chivasso, Italy.
authors: Anna
authors: A
authors: Chiambretti
authors: Metabolism and Diabetes Unit, ASL 1, Massa Carrara, Italy.
authors: Fabio
authors: F
authors: Baccetti
authors: Metabolism and Diabetes Unit, ASL di Bari, Rutigliano, Italy.
authors: Francesco M
authors: FM
authors: Gentile
authors: Laboratory of Clinical Epidemiology of Diabetes and Chronic Diseases, Fondazione Mario Negri Sud, Santa Maria Imbaro, CH, Italy.
authors: Giuseppe
authors: G
authors: Lucisano
authors: Laboratory of Clinical Epidemiology of Diabetes and Chronic Diseases, Fondazione Mario Negri Sud, Santa Maria Imbaro, CH, Italy.
authors: Antonio
authors: A
authors: Nicolucci
authors: Laboratory of Clinical Epidemiology of Diabetes and Chronic Diseases, Fondazione Mario Negri Sud, Santa Maria Imbaro, CH, Italy.
authors: Maria Chiara
authors: MC
authors: Rossi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007003:Hypoglycemia / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D006442:Glycated Hemoglobin
keywords: Hypoglycemia; Incidence; Risks factors; Type 1 diabetes