title: Diabetes screening intervals based on risk stratification.
abstract: BACKGROUND
  Guidelines for frequency of Type 2 diabetes mellitus (DM) screening remain unclear, with proposed screening intervals typically based on expert opinion. This study aims to demonstrate that HbA1c screening intervals may differ substantially when considering individual risk for diabetes.
  
  
  METHODS
  This was a multi-institutional retrospective open cohort study. Data were collected between April 1999 to March 2014 from one urban and one rural cohort in Japan. After categorization by age, we stratified individuals based on cardiovascular disease risk (Framingham 10-year cardiovascular risk score) and body mass index (BMI). We adapted a signal-to-noise method for distinguishing true HbA1c change from measurement error by constructing a linear random effect model to calculate signal and noise of HbA1c. Screening interval for HbA1c was defined as informative when the signal-to-noise ratio exceeded 1.
  
  
  RESULTS
  Among 96,456 healthy adults, 46,284 (48.0%) were male; age (range) and mean HbA1c (SD) were 48 (30-74) years old and 5.4 (0.4)%, respectively. As risk increased among those 30-44 years old, HbA1c screening intervals for detecting Type 2 DM consistently decreased: from 10.5 (BMI <18.5) to 2.4 (BMI > 30) years, and from 8.0 (Framingham Risk Score <10%) to 2.0 (Framingham Risk Score ≥20%) years. This trend was consistent in other age and risk groups as well; among obese 30-44 year olds, we found substantially shorter intervals compared to other groups.
  
  
  CONCLUSIONS
  HbA1c screening intervals for identification of DM vary substantially by risk factors. Risk stratification should be applied when deciding an optimal HbA1c screening interval in the general population to minimize overdiagnosis and overtreatment.
authors.affiliation: Center for Clinical Epidemiology, St. Luke's International University, 10-1 Akashi-cho, Chuo, Tokyo, 104-0044, Japan. saohde@luke.ac.jp.|Department of Health Science, Basic Science for Clinical Medicine, Division of Medicine, Graduate School Department of Interdisciplinary Research, University of Yamanashi, Kofu, Japan. saohde@luke.ac.jp.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ohde
authors.affiliation: Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
authors.forename: Emily
authors.initials: E
authors.lastname: McFadden
authors.affiliation: Center for Clinical Epidemiology, St. Luke's International University, 10-1 Akashi-cho, Chuo, Tokyo, 104-0044, Japan.|Department of General Internal Medicine, St. Luke's International Hospital, 9-1 Akashi-cho, Tokyo, 104-8560, Japan.|Department of Internal Medicine, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Gautam A
authors.initials: GA
authors.lastname: Deshpande
authors.affiliation: Department of Health Science, Basic Science for Clinical Medicine, Division of Medicine, Graduate School Department of Interdisciplinary Research, University of Yamanashi, Kofu, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokomichi
authors.affiliation: Center for Clinical Epidemiology, St. Luke's International University, 10-1 Akashi-cho, Chuo, Tokyo, 104-0044, Japan.|Department of General Internal Medicine, St. Luke's International Hospital, 9-1 Akashi-cho, Tokyo, 104-8560, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Takahashi
authors.affiliation: Center for Clinical Epidemiology, St. Luke's International University, 10-1 Akashi-cho, Chuo, Tokyo, 104-0044, Japan.|Department of General Internal Medicine, St. Luke's International Hospital, 9-1 Akashi-cho, Tokyo, 104-8560, Japan.
authors.forename: Tsuguya
authors.initials: T
authors.lastname: Fukui
authors.affiliation: Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK.
authors.forename: Rafael
authors.initials: R
authors.lastname: Perera
authors.affiliation: Department of Health Science, Basic Science for Clinical Medicine, Division of Medicine, Graduate School Department of Interdisciplinary Research, University of Yamanashi, Kofu, Japan.
authors.forename: Zentaro
authors.initials: Z
authors.lastname: Yamagata
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D059629:Signal-To-Noise Ratio; D013997:Time Factors
chemical_list: D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Accuracy of testing; Diabetes mellitus; Screening interval