Significance of diagnostic and monitoring criterion of HbA1c as compared with fasting and 2-hour plasma glucose concentration in GCS general hospital, Ahmedabad: a retrospective study

Background: Diabetes is a chronic disorder that has reached epidemic levels. Its complications are potentially life-threatening but can be slowed by early diagnosis and treatment. Complications develop earlier in patients having more fluctuating levels of blood glucose than those having maintained levels. Early diagnosis and treatment confer more benefits than aggressive control.Methods: As it was a retrospective study; the data was collected from available records of patients in whom all the three tests have been executed and analysed using SPSS version 26.Results: Diabetics were 199 (53.9%) based on FPG (fasting plasma glucose); 169 (45.8%) based on 2hPG (2-hour plasma glucose) and 230 (62.3%) based on HbA1c. When diagnosed with FPG, the sensitivity and specificity of HbA1c was 89.44% and 69.41% respectively, whereas with 2hPG it was 92.89% and 63.5%. When HbA1c was compared with FPG and 2hPG, the values are affected with history of diastolic hypertension and family history of diabetics. The values correlated with that of FPG as well as 2hPG and showed linear relationship. The regression equation HbA1c (%)=3.737+0.027×FPG (mg/dl) explains 50.4% of variation and with less error when compared to 2hPG. Hence, the values of FPG can be used to predict the approximate values of HbA1c through regression.Conclusions: Study revealed that HbA1c has a greater potential as a diagnostic test due to its high sensitivity. The levels are affected by family history and diastolic hypertension. Our study suggests that diagnosing criteria of diabetes should be HbA1c ≥7.1% instead of the current criteria of HbA1c ≥6.5% by the relationship of HbA1c with FPG