Objective: The purpose of this study was to assess how the risks of glycemic stage transitions observed in clinical practice vary with body mass index (BMI). These transitions included progression from euglycemia ('normal') to prediabetes (PreD) and from PreD to type 2 diabetes (T2D), as well as from normal directly to T2D, and reversions from PreD to normal.
Methods: We examined the Geisinger Health System electronic health records and insurance claims data, segmenting a subject's medical history into normal, PreD, and/or T2D glycemic stages via diagnosis codes, glycosylated hemoglobin A1c (HbA1c) or fasting plasma glucose lab results, and use of anti-diabetic drugs. Weibull survival models, adjusted for age, gender, race, and smoking, were used to estimate the glycemic progression hazard ratios for BMI categories relative to normal BMI.
Results: The sample included 32,864 adults with normal glycemic levels at baseline and 4483 with PreD. The adjusted hazard ratios for normal to PreD progression ranged from 1.8 (25 ≤ BMI < 30 kg/m(2)) to 6.5 (BMI ≥ 40 kg/m(2)); for PreD to T2D, 1.3 to 2.9; for normal to T2D, 1.8 to 9.5; and for PreD to normal, ∼0.7 across all BMI.
Limitations: The glycemic transitions may be recognized after the true onset since periodic glycemic testing was not required across the study population.
Conclusions: A positive association between the risks of progression along the glycemic continuum and BMI levels was observed in a real-world United States practice setting.
Keywords: Body mass index (BMI); Diabetes; Epidemiology; Obesity; Prediabetes.