Abstract Body: Background: We evaluated changes in type 2 diabetes (T2D) incidence associated with onset of the COVID-19 pandemic shelter-in-place (SIP) mandate; and if changes were greater among public (Medicaid) vs. commercially insured patients, and Asian, Black, and Hispanic vs. White patients, who have greater T2D risks.

Methods: We examined electronic health records of 323,609 adults ages ≥18-89 years with BMI ≥25 (≥23 if Asian) and prediabetes (fasting glucose 100-125 mg/dL, or A1c 5.7-6.4%) from 1-1-2019 to 12-31-2021, at Kaiser Permanente Northern California. We defined T2D as having one inpatient discharge diagnosis or any of the following two within 24 months: A1c ≥6.5%, fasting glucose ≥126 mg/dl, random glucose ≥200 mg/dl, 2-hour 75-g oral glucose tolerance test ≥200 mg/dl, outpatient diagnosis code, and/or filled T2D medication. In a sub-analysis, we used only the first positive lab test in the T2D range. Using an interrupted time-series analysis, we evaluated whether an increase in T2D incidence was associated with the start of the pandemic SIP mandate (March 2020). The analysis was operationalized by fitting segmented linear regression models using generalized least squares, accounting for autocorrelation, and with monthly cases per 10,000 patients as the outcome.

Results: In the 10 months before the pandemic SIP mandate, the average monthly T2D incidence was 12.2 cases (and 268 lab positivity cases) per 10,000 patients with stable trends. At the start of the SIP mandate, there was a nonsignificant steady increase in the monthly incidence of 0.8 (95% CI: -0.2,1.8) cases/month which persisted through 2021. There was also a steady and significant increase in the monthly lab positivity incidence rate of 8 (1, 16) cases/month, which persisted through 2021. In stratified analyses of lab positivity changes, the rate increase was similar across insurance types. However, compared to White patients, at the start of the SIP mandate, there was an immediate significantly greater increase in lab positivity of 104 (75, 133) cases/month for Hispanic patients, followed by an increase in monthly incidence that continued through 2021. There were no differences between Asian or Black and White patients.

Conclusion: The COVID-19 pandemic and SIP mandate were associated with a steady increase in the T2D lab positivity rate among adults with prediabetes that persisted through 2021. The increase was larger among Hispanic compared to White patients, reflecting disparities.