Relationship between glycated haemoglobin 1c and red blood cell parameters in type 2 diabetes patients at Bungoma county referral hospital, Kenya

Abstract

Diabetes mellitus (DM) is among the leading global health concerns, causing over 1.5 million deaths alongside other significant comorbidities and complications. Conventional diagnoses have revolved around estimating fasting, random blood glucose levels and glucose tolerance test. For monitoring purposes, long-term glycaemic control has been achieved through the measurement of glycated haemoglobin (HbA1c), which is considered a reliable and preferred marker for DM. However, it could be affected by red blood cell parameters such as haemoglobin levels (Hb), Mean corpuscular haemoglobin (MCH), Mean corpuscular volume (MCV) and mean corpuscular haemoglobin concentration (MCHC).Furthermore, it could be affected by haemoglobin types like HbA, HbA2, and HbF concentrations whose magnitude remains unclear. As such, the current study investigated these potential interferences, which constitute the problem under investigation. It sought to determine the association between HbA1c and red cell parameters, assess the relationship between HbA1c and haemoglobin types, and find out the association between haemoglobin types and red cell parameters among patients with type 2 diabetes mellitus. The purpose of the study was to explore possible HbA1c interference and how it relates to red blood cell parameters and haemoglobin types. The study sought to supplement the existing literature on possible HbA1c interferences, which has been unavailable in reference to the local population, and help inform the formulation of local policies regarding DM monitoring. In this cross-sectional study, 72 participants presenting with T2DMand 72 controls at the Bungoma County Referral Hospital were recruited using simple random sampling. Bungoma County was a suitable study due to a cited higher T2DM burden within the region. Red cell parameters were analysed using the Celtac G MEK-9100K machine (Nihon Kohden Europe). HbA1c and other Haemoglobin variants were measured using ion-exchange high-performance liquid chromatography (HPLC) by the Bio-Rad D-10 machine (Bio-Rad Laboratories, Inc). Chi-square (2) analysis was used to determine the differences between proportions. Mann-Whitney U test was used to compare laboratory characteristics between type 2 DM and non-diabetics. With HbA as the reference group, the association between HbA1c and red blood cell parameters was determined using binary logistic regression while controlling for uncontrolled diabetes status. The relationship between HbA1c and haemoglobin types was determined using binary logistic regression. Association between haemoglobin types and red blood cell parameters was determined using Pearson correlation. Haemoglobin p=0.003, MCH p=0.007 and MCHC p=0.001 were markedly increased in diabetic patients relative to non-diabetics. With non-diabetics as the reference group, HbA1c was associated with increased HbA0 [OR=1.059, 95% CI=1.020-1.099, p=0.003] and increased HbA2 [OR=3.893, 95% CI=2.161-7.014, p=0.001]. However, there was no significant association between HbA1c and HbF[OR=2.062, 95% CI=0.873-4.875, p=0.099].HCT had a negative correlation with HbAO (r= -0.271, p=0.021) and a positive correlation with HbAS (r= 0.292, p=0.013) in participants with controlled diabetes.MCV and MCH had a negative correlation with HbF, (r= -0.291, p=0.013) and(r= -0.298, p=0.011) respectively. MCH had a negative correlation with HbA2 (r= -0.389, p=0.001) in participants with uncontrolled diabetes. In conclusion,HbA1c was not significantly associated with red blood cell parameters while it significantly correlated with haemoglobin types in T2DM. Additionally, HCT correlated negatively with HbA0 and positively with HbAS, while MCV and MCH had a negative correlation with HbF for the diabetic participants. Thus, Hb types are potential interferences in HbA1c estimation while RBC parameters are not.