Diabetes incidence before and after the pandemic onset in adult subgroups with prediabetes

OBJECTIVES: During the COVID-19 pandemic, type 2 diabetes (T2D) incidence increased, but it remains unclear if different groups were disproportionately affected. We evaluated overall changes in T2D incidence before and during the pandemic and by insurance type, sex, and race/ethnicity subgroups. STUDY DESIGN: Retrospective dynamic cohort. METHODS: (or ≥23 if Asian) using electronic health record data from Kaiser Permanente Northern California (2019-2021). T2D was defined comprehensively with diagnosis codes, glycemic tests and/or filled diabetes medications. In secondary analyses, T2D was defined by the first diabetes-range lab test among screened adults. Sensitivity analyses addressed screening bias using inverse probability weighting and propensity scores. An interrupted time-series analysis assessed T2D incidence changes following the pandemic onset (March 2020). RESULTS: Before the pandemic, monthly T2D incidence was stable. After the pandemic onset, the monthly trend increased by 6.5 % (-0.2 %, 10.3 %) for comprehensive and 3.2 % (0.6 %, 5.1 %) for lab-only; both trends persisted through 2021. After accounting for differential screening bias this increase remained but was not significant given wider confidence intervals. T2D incidence level for lab-only increased 51 % more among Hispanic vs. White adults and persisted through 2021. No other group differences were observed. CONCLUSIONS: The pandemic onset was followed by an increase in T2D incidence overall and with sharper increases among Hispanic adults. This highlights the broader health changes of the pandemic and underscores the need for public health strategies to manage this growing burden.