Association Between Haemoglobin Levels and Glycated Hemoglobin (Hba1c) in Diabetic Patients: A Case Control Study at Pentecost Hospital, Ghana

Research Article

Austin Diabetes Res. 2024; 9(1): 1029.

Association Between Haemoglobin Levels and Glycated Hemoglobin (Hba1c) in Diabetic Patients: A Case Control Study at Pentecost Hospital, Ghana

Appiah M1*; Ashiagbor F1; Nyarko ENY2; Ametepe S4; Aidoo KE1; Lokpo S3; Duku TR1

1Department of Medical Laboratory Technology, Accra Technical University, Ghana

2Department of Chemical Pathology, University of Ghana Medical School, University of Ghana, Ghana

3Department of Medical Laboratory Sciences, School of Allied Health Sciences, University of Health & Allied Sciences, Ghana

4Department of medical laboratory science, Koforidua Technical University, Ghana

*Corresponding author: Appiah M Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana. Tel: +233243324633 Email: mappiah@atu.edu.gh

Received: January 23, 2024 Accepted: March 01, 2024 Published: March 08, 2024

Abstract

Background: Evaluation of HbA1c in diabetics has been found to be disconcerted by factitious results in anaemic diabetics. The degree of effect has however not been well established.

Aim: The primary objective of this research was to examine how changes in haemoglobin concentration impact HbA1c levels.

Methods: This study involved a hospital-based case-control approach, encompassing a total of 200 participants. The cohort included 100 diabetic and 100 non-diabetic patients, all of whom were receiving healthcare services at Pentecost Hospital. Convenience sampling method was employed. A 5 mL venous blood sample was drawn from each participant under aseptic circumstances. Following this, 2 mL of the venous blood was dispensed into fluoride oxalate tubes for the assessment of glucose levels, while the remaining 3 mL was carefully transferred into Ethylenediamine Tetra Acetic acid (EDTA) tubes to facilitate a comprehensive analysis of full blood count and HbA1c levels. The data collected was analyzed using Microsoft Excel 365 and SPSS software version 25.

Results: In the cohort of diabetic participants, a statistically significant linear relationship was established between the degree of anaemia and HbA1c levels, as indicated by a p-value less than 0.001. Concurrently, non-diabetic subjects demonstrated a statistically significant linear trend in HbA1c, also evidenced by a p-value less than 0.001. Additionally, a p-value of 0.002 indicated a statistically significant association between glycated Haemoglobin (HbA1c) and fasting plasma glucose levels among the diabetic subgroup. Conversely, this correlation failed to attain statistical significance among non-diabetic individuals, with a p-value of 0.690.

Conclusion: Monitoring diabetics solely based on HbA1c may be deceptive. It is recommended that clinicians exercise prudence by incorporating the anaemic status of diabetic patients into their therapeutic decision-making processes, particularly when relying exclusively on HbA1c assessments.

Keywords: Haemoglobin; HbA1c; Anaemia; Diabetes mellitus

Introduction

Diabetes mellitus is on the rise globally. According to estimates provided by the International Diabetes Federation (IDF), 537 million persons worldwide have diabetes in 2021.This projection indicates that the figure is expected to reach 643 million by 2030 and escalate further to 783 million by 2045. The glucose-haemoglobin complex known as glycated Haemoglobin (HbA1c) is created when hemoglobin undergoes irreversible, non-enzymatic glycation. When glucose attaches itself to the N-terminal valine residue on the beta chain of hemoglobin, the process known as glycation produces HbA1c. Haemoglobin A1c (HbA1c) is a common test for diabetes diagnosis, monitoring and management. The benefits of HbA1c over other glycemic control monitoring parameters include its stability in samples and the needlessness of fasting before the test Regardless of its advantages, HbA1c can be influenced by genetic, physiological, haematological, and other pathological variables. Conditions that affect haemoglobin, RBC turnover, and haemoglobin glycation can affect HbA1c levels independently of blood glucose. Since the HbA1c value represents the portion of total haemoglobin that is glycated, it is possible that the haemoglobin level influences HbA1c test results separately from glycemia. Several studies including those by [4,10,11] have been conducted to study the correlation between haemoglobin and HbA1c in diabetes mellitus. Nevertheless, there is inconsistent reporting on how anemia affects HbA1c in these investigations. Anaemia may result in an incorrect rise or fall in HbA1c concentration, misrepresenting the state of the disease. There is also dearth of information on the relationship between HbA1c and anaemic status in Ghana. In this study, it was hypothesized that HbA1c was lower in diabetic patients who are anaemic.

Materials and Methods

Study Design

This study examined the relationship between hemoglobin levels and HbA1c concentration in individuals with and without diabetes at the Pentecost Hospital from June 2022 to August 2022. It was a case control investigation.

Participants

The study population consisted of 100 diabetics who attended the Pentecost hospital diabetic clinic and 100 non-diabetic patients who presented at the Outpatients’ Department of the Pentecost Hospital between June and August 2022. The sample size was calculated using the Cochran’s equation, with a diabetes prevalence of 6.46%, a confidence level of 95% and an error margin of 5%. Adult diabetics (type 1 and 2) who have been managed for diabetes at the Pentecost hospital clinic for at least two years were included in the study. Patients taking any type of oral iron supplements, acute diabetic complications, recent history of surgery, those who have had a recent accident or trauma leading to acute haemorrhage, those who have had a recent blood transfusion and pregnant patients were not included in the study.

Methods

Five milliliters (5ml) of blood were obtained using a 5cc 21-gauge hypodermic syringe. 2ml of the blood was transferred into fluoride oxalate tubes and the remaining 3ml was transferred into EDTA tubes. The test tube was labelled appropriately with the name and ID number given to the participant during the research. The EDTA anticoagulated blood was tested for full blood count to obtain haemoglobin concentration using Urit 5250 fully automated haematology analyzer (Medtek, China) and HbA1c using FinecareTM FIA Meter Plus (Wondfo, China). After centrifugation, the plasma from the fluoride oxalate tubes were analyzed for glucose estimation using Mindray BS 430 chemistry analyzer (Mindray, China). Haemoglobin level was classified as normal (males -13 to 17g/dL, females - 12 to 16g/dL), mild anaemia (males - 10 to 12.9g/dL, females – 10 to 11.9g/dL), mild anaemia (males – 8 to 9.9g/dL, females – 8 to 9.9g/dL) and extreme anaemia (males - <7.9g/dL, females - <7.9g/dL).

Statistical Analysis

Descriptive statistics, encompassing measures such as frequency, percentage, range, mean, and standard deviation, were employed for comprehensive data characterization of the sex-wise distribution of anaemia in participants and the dependent variable (HbA1c). The relationship and degree of the association between haemoglobin level and HbA1c were examined using scatter plots, Pearson correlation and regression analysis. If the p-value was less than 0.05, the statistical significance criterion was deemed significant.

Results

General Characteristics of Study Participants

Table 1 displays the descriptive statistics for the study sample, providing an overview of the key characteristics of the participants. The diabetic participants were significantly older (59.03±14.78 years) than the non-diabetic participants (49.81±16.28 years, P<.001). No significant difference was found between the haemoglobin level in diabetics (11.91±2.41g/dL) and non-diabetics (12.36±2.30g/dl, P=.181), although the non-diabetic participants had a slightly higher haemoglobin level than the diabetics.