MON-LB045 Inaccurate Hemoglobin A1c in a Transman Patient with Diabetes: Implications for Treatment and Surveillance

Background: HbA1c is the standard biomarker to monitor glycemic control and to prevent diabetes complications. Conditions (hemolysis, reticulocytosis), or drugs (erythropoietin, dapsone), known to affect the lifespan of red blood cells have an impact on HbA1c’s accuracy. Testosterone therapy (TT) is the mainstay of treatment in transmen. Testosterone regulates erythropoiesis, increasing hemoglobin and hematocrit in a dose dependent manner. There is currently no data on the effect of TT on HbA1c accuracy in transmen with diabetes. Methods: we present a 52 year-old well virilized transman evaluated for polycythemia in the setting of 10 years of TT; “well controlled” type 2 diabetes, on diet alone for 11 years; diabetic neuropathy, hypertension, CKD stage 3, and rheumatoid arthritis. Medications included weekly testosterone cypionate, lisinopril, gabapentin, and etanercept. Creatinine was 1.6mg/dL, GFR 55mL/min, +microalbuminuria. Hb was 18.7g/dL, Hematocrit 56%, RBCs 6.30/uL, HbA1c 6.2%-6.4% in the last 2 years. Data from SMBG indicated 58.4% of readings to be above the fasting target of 70-130mg/dL, and postprandial target of 70-180mg/dL. Given the discrepancies of capillary glucose and HbA1c, and the presence of complications, the patient was evaluated with a 5-day professional CGM, and alternative glycemic markers. CGM average glucose was 163mg/dL, equivalent to HbA1c of 7.3%. Fructosamine was 316umol/L (ref: 200-285umol/L), equivalent HbA1c 7.5%; 1, 5-anhydroglucytol was 8.9 (ref: 10.7-32.0ug/mL) indicating postprandial hyperglycemia. Discussion: We hypothesize that the patient had unrecognized long-term suboptimal diabetes control, secondary to inaccurate HbA1c in the context of TT. Diabetes is a major risk factor for CV disease. In cisgender men the data on TT and the risk of major CV events is controversial and long-term effects from TT on CV health are unknown. TT in transmen is associated with an increase in triglycerides, systolic blood pressure and a decrease in HDL cholesterol. These risk factors in combination, in a diabetes background may augment the risk of CV disease in transmen, as such early and aggressive glucose control and management of risk factors is of critical importance. Clinicians need to be aware of HbA1c’s limitations in this population with diabetes, to prevent delays in diagnosis and timely intensification of treatment. Better tools for screening and monitoring diabetes in transmen are needed. Conclusion: This is the first case showing the inaccuracy of HbA1c in a transman patient with diabetes, raising awareness of the need for alternative methods of diabetes screening and monitoring, in this growing and potentially high-risk for CV disease population. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.