Higher Medical Care Costs Accompany Impaired Fasting Glucose

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Abstract
OBJECTIVE—The purpose of this study was to estimate medical costs associated with elevated fasting plasma glucose (FPG) and to determine whether costs differed for patients who met the 2003 (≥100 mg/dl) versus the 1997 (≥110 mg/dl) American Diabetes Association (ADA) cut point for impaired fasting glucose. RESEARCH DESIGN AND METHODS—We identified 28,335 patients with two or more FPG test results of at least 100 mg/dl between 1 January 1994 and 31 December 2003. Those with evidence of diabetes before the second test were excluded. We categorized patients into two stages of abnormal glucose (100–109 mg/dl and 110–125 mg/dl) and matched each of these subjects to a patient with a normal FPG test (<100 mg/dl) on age, sex, and year of FPG test. All subjects were followed until an FPG test qualified them for a higher stage, dispensing of an antihyperglycemic drug, health plan termination, or 31 December 2003. RESULTS—Adjusted annual costs were $4,357 among patients with normal FPG, $4,580 among stage 1 patients, and $4,960 among stage 2 patients (P < 0.001, all comparisons). After removing patients with normal FPG tests whose condition progressed to a higher stage or diabetes, costs in the normal FPG stage were $3,799. Patients in both stages 1 and 2 had more cardiovascular comorbidities than patients with normal FPG. CONCLUSIONS—Our results demonstrate that abnormal glucose metabolism is associated with higher medical care costs. Much of the excess cost was attributable to concurrent cardiovascular disease. The 2003 ADA cut point identifies a group of patients with greater costs and comorbidity than normoglycemic patients but with lower costs and less comorbidity than patients with FPG above the 1997 cut point.