Cross Sectional Study on Prevalence of Falsely Low HbA1c in Diabetic Patients on Dapsone Therapy

Abstract

Background : Diabetes is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes is associated with long-term damage, dysfunction, and failure of different organs, especially the eyes, kidneys, nerves, heart, and blood vessels.[1] Objective: The aim of our study was to establish the prevalence of falsely low HbA1c in diabetes patient on dapsone therapy and the possible mechanism behind it. Study design: we conducted a retrospective Cross-sectional study on 30 subjects more than or equal to 18yrs attending the Endocrinology and Dermatology outpatient department (OPD ) ,patients with diabetes mellitus on oral anti diabetic drugs and or insulin therapy on dapsone therapy and patients on documented dapsone therapy for Hansen’s disease or any other skin condition were eligible for enrolment. HbA1c measured by HPLC(high performance liquid chromatography) was compared with expected A1c value suggested by other parameters like fructosamine assay and mean blood glucose. Also other parameters of haemolysis was measured to establish the possible mechanism behind the falsely low A1c. Results: Out of 30 subjects 25 patients were found to have low HbA1c value compared to their fructosamine assay and expected HbA1c. Prevalence of inappropriately low A1c was 25(83.45%) ,16 of them in diabetic group (53.3%) and 9 in non-diabetic group (30.0%).. There were higher number of subjects in discordance group with >2% methaemoglobin with marginally positive correlation .Factors of haemolysis too was higher in more number of subjects [reticulocyte count (18.2%) mcv(90.9)LDH(86.6%)] in discordance Hba1c group compared to cordance HbA1c group but was not statically significant owning to small sample size. Conclusion :The prevalence of falsely low A1c in patient on dapsone therapy was as high as 83.5% and possible reason for this being hemolysis suggesting there are a number of drugs, some of them quite commonly used, which can cause inappropriately high or low HbA1c levels for the degree of glycemia