SUN-154 Identifying Type 1 Diabetes in Electronic Medical Records and Administrative Health Data in Ontario: A Validation Study

Abstract

Background There has been growing interest in using administrative and electronic medical record (EMR) data to identify type 1 diabetes (T1D) for clinical and health services research. Our aim was to create an algorithm identifying T1D using EMR data alone and/or in combination with administrative data in Ontario, Canada. Methods The Electronic Medical Record Administrative data Linked Database (EMRALD) was used to create a reference standard for diabetes type as determined by chart abstraction by an endocrinologist. EMRALD contains data from over 350 family physicians using Practice Solutions® EMR. We included patients receiving care from participating physicians who were diagnosed with diabetes prior to Sept 30, 2015. A random 25% sample of patients with diabetes (identified using a validated algorithm) were selected for the reference standard. Patients who were not prescribed insulin or who were prescribed insulin and an oral hypoglycemic agent other than metformin were automatically classified as not having T1D without chart abstraction. Remaining patients underwent chart abstraction to determine diabetes type. 50 charts were randomly re-abstracted for inter- and intra-rater reliability. Characteristics of patients by diabetes type were reviewed to select variables for algorithm inclusion. Preliminary Results There were 23,310 patients with diabetes as of September 30, 2015. The reference standard consisted of 5828 patients: 5305 were classified as not T1D without chart abstraction and 523 underwent chart abstraction. Inter- and intra-rater reliability were high (Cohen’s kappa 0.82 and 0.96, respectively). After chart abstraction,14 patients were classified as not having diabetes, 233 patients were classified as T1D (45.8%), 261 as not T1D (51.3%), and 15 as possible T1D (2.9%). The prevalence of T1D was 4.0%. Compared to 5581 patients without definite T1D, patients with T1D were younger (median 40 years [IQR 30-53] v. 66[57-75]), had a younger age of onset (15 years [10-25] v. 47[40-55]), and a lower body mass index (BMI) (26±5 v. 32±8). Age at diagnosis and BMI were documented in 349(71.8%) of abstracted charts and 1386(23.8%), respectively. Renal insufficiency (eGFR <30ml/min, dialysis, or renal transplant) was present in 13(5.6%) and 136(2.4%) patients with and without T1D, respectively. Metformin use was uncommon in patients with T1D compared to those without T1D [15(6.4%) v. 4223(75.7%)]. Bolus insulin was recorded by the primary care physician for 115(49.4%) patients with T1D and 490 (8.8%) patients without T1D. For patients with T1D, 65(27.9%) used an insulin pump and 41(21.4%) had a history of diabetic ketoacidosis. Conclusions Age, age at diagnosis, BMI, medications, and insulin pump use differed between subjects with and without T1D. Future work includes development of algorithms incorporating these variables and variables from other data sources to identify T1D.