Prevalence of Prediabetes and Newly Diagnosed Diabetes in Patients with a Transient Ischemic Attack or Stroke

BACKGROUND: Patients with a transient ischemic attack (TIA) or stroke and prediabetes or newly diagnosed diabetes are at high risk of recurrent stroke or cardiovascular events. This underlines the importance of accurate screening for impaired glucose metabolism in clinical practice. Fasting plasma glucose levels are currently the most commonly measured glycemic parameter to detect prediabetes or diabetes, even if 2-hour postload glucose and glycosylated hemoglobin levels can be used as well. We assessed the prevalence of prediabetes and newly diagnosed diabetes with different screening methods, including fasting plasma glucose, 2-hour postload glucose and glycosylated hemoglobin levels in consecutive patients with recent TIA, ischemic stroke or intracerebral hemorrhage admitted to the stroke unit or visiting the specialized TIA outpatient clinic in the Erasmus Medical Center, Rotterdam, The Netherlands. METHODS: We measured fasting plasma glucose, 2-hour postload glucose and glycosylated hemoglobin levels in 269 patients with a TIA, 374 with ischemic stroke and 57 with intracerebral hemorrhage, all without a history of diabetes mellitus. Prediabetes was defined as fasting plasma glucose levels of 5.6-6.9 mmol/l and/or 2-hour postload glucose levels of 7.8-11.0 mmol/l and/or glycosylated hemoglobin levels of 5.7-6.4%. Newly diagnosed diabetes was defined as fasting plasma glucose levels of ≥7.0 mmol/l and/or 2-hour postload levels of ≥11.1 mmol/l and/or glycosylated hemoglobin levels of ≥6.5%. The diagnosis was based on a one-time measurement. RESULTS: Based on fasting plasma glucose, 2-hour postload glucose and glycosylated hemoglobin levels combined, 365 patients (52%) were identified as prediabetics and 188 (27%) as having newly diagnosed diabetes. Patients with intracerebral hemorrhage had more often newly diagnosed diabetes compared with patients with an ischemic stroke or a TIA [27 (47%) and 161 (25%), respectively; p < 0.001]; the prevalence of prediabetes was similar. Newly diagnosed diabetes was identified more frequently by 2-hour postload glucose levels (n = 162; 23%) than by fasting plasma glucose (n = 49; 7%) or glycosylated hemoglobin levels (n = 36; 5%). About one third of the patients with normal fasting glucose levels has impaired glucose tolerance or elevated glycosylated hemoglobin levels. CONCLUSIONS: Prediabetes and newly diagnosed diabetes are highly prevalent in patients with a TIA or stroke. The majority of these patients would not have been identified by fasting plasma glucose levels alone. Both 2-hour postload glucose and glycosylated hemoglobin levels identify more patients with a disturbed glucose metabolism.