PERL Continuous Glucose Monitoring (CGM) Study

Participants who consent to the study will have an Abbott Freestyle Libre Pro sensor placed
on the back of their upper arm at their first PERL visit after this ancillary study has begun
and at all subsequent PERL Visits. The sensor will be continuously worn by participants for
14 days. At the end of the 14 days, the sensor will be removed and mailed by the participant
to the Coordinating center. Since subjects are at various stages of the PERL protocol, the
number of remaining visits at which the CGM will be applied will vary among subjects.

STUDY AIMS

1. To assess the effect of glycemic variability, as measured by the coefficient of
variation of CGM glucose (CV, the ratio of standard deviation and the mean of CGM
glucose values), on the PERL renal functional endpoint (iohexol GFR at the end of
study).

2. To assess the effect of other glycemic parameters measured by CGM (mean glucose, % time
70-180 mg/dL, % time below 54 mg/dL, % time below 70 mg/dL, % time above 180 mg/dL, %
time above 250 mg/dL, mean amplitude of glucose excursions [MAGE], low blood glucose
index [LBGI], high blood glucose index [HBGI]) on the PERL renal functional endpoint.

3. To assess the relationship between CGM-measured glycemic parameters and HbA1c at various
levels of renal function.

4. To compare the effects of CGM metrics on the PERL renal endpoint and the corresponding
effect of HbA1c.

5. To assess the effect of allopurinol treatment on all of the different glycemic metrics
including HbA1c, CV, etc. and on their association with the PERL renal endpoint.

Inclusion Criteria:

• Being an active participant in the PERL clinical trial

Exclusion Criteria:

- Having completed PERL Visit 16

- Pregnancy

- History of skin reactions in relation to the application of Abbott Freestyle Libre Pro