Impact of new diagnostic criteria of diabetes mellitus

Abstract

Objective: To compare the frequency of diabetic individuals diagnosed by fasting plasma glucose (FPG) > or = 7.0 mmol/L with previous value i.e. > or = 7.8 mmol/L and to determine the diagnostic accuracy of FPG > or = 7.0 mmol/L.

Design: A cross-sectional study.

Place and duration of study: The Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, from April to July 2003.

Patients and methods: FPG of 5250 subjects was checked to compare the frequency of diabetic subjects diagnosed by FPG > or = 7.0 mmol/L with > or = 7.8 mmol/L. Of them, 301 symptom-free subjects were subjected to 75 g Oral Glucose Tolerance Test (OGTT) and their 2 hours post glucose (2-h PG) challenge level was taken as "gold standard" to determine the diagnostic accuracy of FPG at > or = 7.0 mmol/L.

Results: By lowering the cut off point of FPG from 7.8 mmol/L to 7.0 mmol/L, the percentage of diagnosed diabetic subjects increased from 35% to 42%. Statistical analysis revealed a significant increase (p < 0.0001). FPG > or = 7.0 mmol/L had a diagnostic sensitivity of 70%, specificity 91%, the predictive value of positive and negative diagnosis was 84% and 80% respectively.

Conclusion: FPG at cut off point of >7.0 mmol/L, will greatly facilitate the early diagnosis of diabetes mellitus (DM). An early diagnosis can be further facilitated by a combination of FPG and 2-h PG estimation.