THU266 Lowered HbA1c In Individuals With Long-term Type 1 Diabetes Undergoing BCG Bladder Cancer Therapy

Disclosure: H. Dias: None. W. Kühtreiber: None. D.L. Faustman: None. Originally developed for the prevention of tuberculosis, the bacillus Calmette-Guérin (BCG) vaccine has shown benefit in diverse human diseases, including infection resistance, allergies, multiple sclerosis and autoimmune diabetes. BCG has also been approved in the United States and Europe since 1972 for early-stage bladder cancer, where it is administered commonly as 6 doses via intravesical therapy for 6 weeks (“high-dose intravesical BCG”). We analyzed three large databases-the Management Science Associates database (with Quest Diagnostics data) (N=263 million adults), the Research Patient Data Registry (RPDR) from the Massachusetts General Brigham (MGB) system (N=6.5 million), and data from Optum Labs (OL)(N=45 million) -for a correlation between high-dose intravesical BCG and HbA1c levels in individuals with type 1 diabetes (T1D) and type 2 diabetes (T2D). We identified subjects with documented T1D (N=19) or T2D (N=106) undergoing BCG therapy for bladder cancer, and then retrospectively assessed BCG’s subsequent year-by-year impact on blood sugar trends. T1D records were identified by searching for T1D diagnosis and insulin usage; records showing any history of oral hypoglycemic agents (e.g., metformin) were excluded. T2D records were searched for using T2D diagnosis and exclusion of any T1D diagnosis. No patients had a history of BCG treatment/vaccination other than for bladder cancer. Patients with T1D in the datasets showed downward trends in HbA1c values after high-dose intravesical BCG, but not patients with T2D. The data suggests that high-dose intravesical BCG therapy may contribute towards a drop in HbA1c values in T1D, but not T2D. This is consistent with earlier interventional trials of the BCG vaccine in longstanding T1D. Presentation: Thursday, June 15, 2023