Association between HbA1c and Haemoglobin of Healthy Adults Visiting a Tertiary Care Hospital in India

Objective: To correlate Hemoglobin (Hb) and Glycosylated hemoglobin (HbA1c) levels and to study interquartile differences in HbA1c values of subjects having low Hb (first quartile) vs. High hemoglobin (last quartile).

Methods: We conducted a retrospective study on 1,040 normal healthy adults (Indians and Afghanis) attending a tertiary care hospital to assess the correlation between Hb and HbA1c. Data of past 5 years (2010-2015) was extracted from hospital records. The cohort was divided into 4 groups according to the quartiles of the Hb level (QI = <13 g/dl, QII = 13-14.1 g/dl, QIII = 14.1-15.4 g/dl, QIV >15.4 g/dl). We studied interquartile differences in HbA1c values of subjects having low hemoglobin (first quartile) vs. High hemoglobin (last quartile) values.

Results: The mean of hemoglobin and HbA1c among the Indian subgroup was (13.49 g/dl ± 1.39) and (5.52% ± 0.45) respectively. On the other hand, the mean hemoglobin and HbA1c among Afghani subjects was (14.80 g/dl ± 1.47) and (5.34% ± 0.43), respectively. Mean Hb of Indian males was 14.04±1.28 g/dL and females was 12.56±1.g/dL vs. 15.38±1.16 g/dL in Afghani males and 13.24±1.07 g/dL in Afghani females. Further analysis revealed that HbA1c declines by an average of 0.03% when Hb increases by 1 g/dl in combined dataset. The difference in average FBS level of subjects in quartile 1 of Hb level (99.42 mg/dL) was significantly different from subjects of 4th quartile (95.14 mg/dL), (t = 2.414 and p-value = 0.016).

Conclusion: In our study we had found that Indians have higher BMI, FBS and HbA1c, inspite of having lower Hb as compared to Afghani population. The findings of our study show that with an increase in hemoglobin levels, there is a decrease in Hb1Ac levels. However the same is not clinically significant. Larger studies of subjects with IDA would be useful in examining the impact of IDA on measurement of HbA1c.