Project Summary
Diabetes mellitus is one of the leading causes of death and disability in the United States. With rapidly ris-
ing incidences in the last two decades, diabetes has been reported in over 20% of hospitalized adult patients.
Glycemic control plays an important role to help reduce hospital complications, mortality, and health care cost
for these patients. To achieve optimal glycemic control, continuous glucose monitoring (CGM), which evaluates
interstitial glucose every 1–5 minutes, offers many advantages over the traditional point of care (POC) capillary
glucose testing before meals and at bedtime, including: a panoramic view of glycemic pro¿les, real-time detec-
tion of hypoglycemia and hyperglycemia, remote glucose management, and lower care labor and cost. With the
fast growing utilization of CGM for inpatient diabetes management, developing effective and robust statisti-
cal methods tailored to translate the abundant data from CGM to sound clinical decisions is of timely
importance; however, this area is largely unexplored.
From closely working on a series of multi-center clinical studies that investigated the reliability, safety, and
ef¿cacy of CGM for inpatient use, we recognize substantial barriers for the existing analytic approaches
for CGM data to meet this critical need. These include inadequately accounting for special data issues in
inpatient CGM studies, and inef¿cient use of the rich information from CGM to inform more individualized
diabetes care. Speci¿cally, time-in-range (TIR), de¿ned as the percentage of time that glucose readings are
within a target glycemic range over a speci¿ed amount of time, is a key metric for evaluating glycemic control
based on CGM. To evaluate TIR in the hospital setting, a prevalent issue is that some patients are discharged
before suf¿cient CGM data are captured. As inpatient glucose excursion patterns can be highly variable over time,
current data analyses that simply impute TIR based on the shorter, incomplete glucose monitoring can lead to
biased inferences on TIR. Another notable caveat relates to the assessment of hypoglycemia and hyperglycemia,
which plays an important role in treatment decisions. Existing analyses mainly use the counts of these events
but waste the valuable timing information that is uniquely available in CGM studies. This leads to a missed
opportunity for detailed individual pro¿ling and dynamic prediction of hypoglycemia or hyperglycemia risk that
can help guide customized inpatient care of diabetes. In this application, we aim to ¿ll in these gaps through
(i) developing rigorous statistical methods that are elegantly suited to thoroughly evaluate TIR and other
similar key outcomes with the special data complications in hospital CGM studies properly addressed; (ii)
broadening the paradigm of current CGM data analyses with a new framework of analyzing hypoglycemia
and hyperglycemia outcomes that effectively utilizes the timing information and confers a much improved
view of individual risk of hypoglycemia and hyperglycemia. The proposed methods will be applied to the
several inpatient CGM studies, and user-friendly software will be developed.
