1280-P: The Maturity-Onset Diabetes of the Young (MODY) Calculator Overestimates MODY Probability in Hispanic Youth Free

The applicability of the MODY probability calculator (Shields et al., Diabetologia, 2012) to non-European populations remains unknown. We aimed to test its utility in Hispanic youth. We performed a retrospective chart review of Hispanic youth (<23 years) with diabetes (n=2033) in a large, pediatric tertiary care center in the U.S. We calculated MODY probability for all subjects, splitting into two cohorts in line with the two equations underlying the MODY calculator: Individuals who were started on insulin within 6 months of diabetes diagnosis (Cohort 1) and those who were not (Cohort 2). MODY genetic testing was carried out on limited individuals based on clinicians’ suspicion of MODY. Cohort 1 and Cohort 2 comprised 1566 (mean age: 15.8 ± 4.7 years, 49% female) and 467 youth (mean age: 17.2 ± 3.5 years, 62% female), respectively. Of 1566 early insulin treated individuals in cohort 1, the mean MODY probability was 6% suggesting an expected 6% (94 individuals) with MODY. This is higher than previous prevalence estimates (1-4%) and much higher than the number identified from genetic testing (6 individuals out of 30 tested). For the 467 non-insulin treated individuals (cohort 2), the mean probability was 62% suggesting an expected 289 individuals with MODY, which again was much higher than previous prevalence estimates and the number identified from genetic testing (10 individuals out of 12 tested). Individuals with a confirmed pathogenic variant in a MODY-associated gene were more likely to have a younger age at diagnosis and lower non-HDL (cohort 1) or lower HbA1c (cohort 2). However, both cohorts had similar MODY probabilities compared to the remaining individuals in each cohort. The MODY calculator likely overestimates the probability of MODY in Hispanic youth, particularly those who are not early insulin treated, where young-onset type 2 diabetes is the more likely diagnosis. The calculator needs updating for use in this population.