Prediction of Diabetes By Utilizing One Hour Glucose Values in Oral Glucose Tolerance Tests – Is It Better Than Conventional Criteria?

Presentation Number: FP17-5
Date of Presentation: June 16th, 2013

Subramanian Kannan*1, James Bena1, Seenia Varghese Peechakara2, Nisha Acharya1 and Marwan Hamaty1
1Cleveland Clinic Foundation, Cleveland, OH, 2Cleveland Clinic Foundation, Lakewood, OH

Abstract

Objective: To evaluate the impact of adding 1hr-PG to ADA criteria of OGTT on predicting future DM.

Methods: Retrospective search using electronic medical record identified 2370 patients who underwent OGTT (included 1hr-PG) from year 2000 to 2010 and had follow up at our institution. Categories of 1hr-PG (mg/dl) are normal (1hr-PG <124) or impaired glucose tolerance (IGT): IGT1 (124-155), IGT2 (156-200) and IGT3 (>200) based on data in the literature. Time to development of diabetes was evaluated using Kaplan-Meier estimates and risk was measured using Cox proportional hazards models.

Results: Among the 2370 patients, 64% were females, 78% were white, Mean (range) age of the cohort was 54.1 yrs (18-90), mean (SD) BMI was 32 (7.8) kg/m2.  Pre-diabetes was diagnosed in 1190 (50%) (Impaired fasting glucose [IFG] 22%, IGT 14%, both IFG and IGT 15%) and 1180 (50%) had normal OGTT per ADA criteria. Abnormal 1hr-PG was seen in 1785 patients (75%) (IGT1 21%, IGT2 33%, IGT3 22%). Among patients with normal OGTT, 673 (57%) had abnormal 1hr-PG. Follow up was for a median of 30 (0-155) months, 11% developed DM in < 1 month. During follow up, 1119 patients (47%) developed diabetes. Among these, at baseline, 687 patients (61%) had abnormal OGTT per ADA criteria, 271 patients (24%) had isolated elevation of 1hr-PG and 161 patients (14%) had both normal OGTT and normal 1hr-PG. Relative to patients with both normal OGTT and normal 1hr-PG, those with isolated abnormal 1hr-PG (673, 28% of total) had progressively increasing DM risk reaching a 3-fold increased risk in those with IGT3 [IGT1 HR 1.26 (1.01 - 1.58), IGT2 HR 1.50 (1.22 - 1.84), IGT3 HR 3.14 (2.43 - 4.06)]. Pre-DM (ADA criteria) had a 2-fold increased risk for developing DM [HR 1.93 (1.71-2.18)].

Conclusions: Adding 1hr-PG to ADA criteria of OGTT significantly improved the prediction of future DM. The proposed categories of IGT were associated with progressive increase of the risk, the highest risk conferred by IGT3.

 

Nothing to Disclose: SK, JB, SVP, NA, MH