Identification of impaired fasting glucose, healthcare utilization and progression to diabetes in the UK using the Clinical Practice Research Datalink (CPRD)

Purpose Few studies have examined patients with prediabetes in usual, "real-world" clinical practice settings. Among patients with impaired fasting glucose (IFG), we aimed to describe the rates of progression to diabetes and to examine the long-term reduction in diabetes risk associated with regression to normoglycemia at 1 year. Methods The UK-based study included 120 055 non-diabetic patients in Clinical Practice Research Datalink from 2001 to 2012 aged 25+ years and with >= 1 fasting plasma glucose (FPG) test between >= 6.1 and <7.0 mmol/l indicating IFG who were followed for progression to diabetes. In a subgroup of 45 167 patients with IFG with subsequent FPG results 1 year later, we assessed the 1-year glycemic status change and estimated the relative hazard of diabetes comparing patients with regression to normoglycemia (IFG-normoglycemia) to those who remained in IFG (IFG-IFG) using a multivariable Cox model. Results Among patients with IFG with over 414 649 person-years of follow-up, 52% received a subsequent FPG test, and 10% developed diabetes within 1 year after recognition of IFG. The incidence rate of diabetes was 5.86 (95% CI: 5.78 to 5.93) per 100 person-years. In the subgroup analysis, 31% of these patients remained in IFG, while 53% and 16% converted to normoglycemia or diabetes, respectively. The adjusted hazard ratio of developing diabetes was 0.33 (95% CI: 0.31 to 0.35) comparing IFG-normoglycemia to IFG-IFG. Conclusions IFG is a high-risk state for diabetes. Regression to normoglycemia from IFG strongly reduces the long-term risk of developing diabetes. Our study also shows the feasibility of identifying patients with IFG in the Clinical Practice Research Datalink. Copyright (C) 2016 John Wiley & Sons, Ltd.