The Effect of Iron Replacement Therapy on HbA1c Levels in Diabetic and Nondiabetic Patients: A Systematic Review and Meta-Analysis

Abstract

Background: Several studies have reported that iron-deficiency anemia (IDA) and its treatment might lead to a distorted reading of glycated hemoglobin (HbA1c) value. Hence, this review aims to systematically investigate the effect of iron replacement therapy (IRT) on HbA1c levels, as the literature is deficient in assessing this clinical phenomenon. Methods: An electronic search of the Cochrane, MEDLINE, and Embase databases was conducted by four independent authors. Results: Among the 8332 articles identified using the search strategy, 10 records (with a total of 2113 participants) met the inclusion criteria and were analyzed. In nine of the studies, IRT was found to decrease HbA1c levels; in the remaining study, IRT was found to increase HbA1c levels. The effect size of the pooled standardized mean difference in HbA1c levels between the treatment and control groups with IDA was 1.8 (95% CI = −0.5, 2.31). Heterogeneity was assessed using the I2 and χ2 tests, and the resultant values were 98.46% and p = 0.09, respectively. Additionally, the mean difference between the HbA1c levels (pre-IRT and post-IRT) showed a drop in the HbA1c levels which ranged from 1.20 to 0.43 mg/dL. Conclusions: The results suggest that IRT decreases HbA1c levels, and it is helpful in treating IDA patients with poor glycemic control. Accordingly, the results provide an added perspective on antidiabetic medication dosing and physicians’ interpretation of initially elevated HbA1c values.

Exploring the Impact of Iron Deficiency Anaemia on Glycated Haemoglobin A1c Levels in Pregnant and Non-Pregnant Women: A Systematic Review

“…Studies have reported a decrease in HbA1c after undergoing IRT, suggesting that it can effectively reduce HbA1c levels. 46 Similarly, this study found that there was a significant decrease in HbA1c after receiving IRT in pregnant women with IDA. These findings could be attributed to the fact that iron plays a critical role in creating haemoglobin.…”

“…[41][42][43][44][45] The literature contains different systematic reviews and meta-analyses that discuss the correlation between IDA and HbA1c levels in this group. [46][47][48][49][50] However, a few studies have discussed their correlation in pregnant women with IDA. 17,[21][22][23][24][25][26] This study conducted a comprehensive review of published data on the effect of IDA on HbA1c among pregnant versus non-pregnant women.…”