Background: Longitudinal biological rhythms in glucose and insulin outputs have not been mapped in individuals with T1D. Physiologically based, within-individual predictions of ultradian (UR), circadian (CR) or longer timescale changes in glucose and insulin are not currently possible, in part due to a lack of understanding of population heterogeneity. This is the first longitudinal analysis of biological rhythms in T1D, compared to non-T1D individuals.

Methods: Frequency decomposition using the continuous morlet wavelet transformation were created to assess change in rhythmic composition of normalized blood glucose data from 5 non-T1D individuals, and anonymized, retrospective CGM data from 19 T1D individuals using a DIY closed loop APS in the OpenAPS Data Commons.

Results: T1D individuals showed a wide range of rhythmic power at the circadian and long-period ultradian timescales compared to individuals without T1D. There is not much UR power lower than 6-hour periodicity, likely due to insulin DIA effects.

Conclusion: Such analysis of biological rhythms should be further studied across a broader T1D population, including both APS and non-users, and knowledge of the rhythms could be used for improving personalization and prediction capabilities of APS.

D.M. Lewis: Consultant; Self; Diabeloop SA, Roche Diabetes Care. A.D. Grant: None.

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