Section 5B - Data Collection (Phase 3 - 1/2011, rev. 8/2011)
Section 5B - Page 5
Cohort
Study
appreciated. However,
for the SEARCH Cohorts Study, we will continue to collect a
random urine sample during the visit for longitudinal analysis. Unique to SEARCH 3,
we will add a first morning void sample that the participant will bring to the clinic.
Urinary albumin and creatinine will be measures to obtain an albumin/creatinine ratio.
Samples will not be collected during the visit on participants who are pregnant or
menstruating, have had a fever greater than 100 degrees in the past 24 hours, or who have
taken an antibiotic in the past seven days for a urinary tract infection. A dipstick test will
also be performed to test for the presence of blood or leukocytes. Urine will also be
stored (first morning void only) to assess other markers of nephropathy in the future.
(08/2011)
Serum cystatin C has been associated not only with renal function, but also positively
associated with coronary calcification among individuals with T1D
(19)
. Serum cystatin C
(20, 21)
and creatinine will be measured for calculation of estimated glomerular filtration
rate (eGFR) using the new Schwartz
equation for children
(22)
. Serum creatinine will be
used to calculate eGFR in subjects over the age of 18, using the CKD EPI equation which
has been demonstrated to be more precise than the modification of Diet in Renal Disease
(MDRD) equation at higher GFRs
(23)
. eGFR will be used to monitor change in filtration
function of the kidney. All three equations will be used in those 14-18 yrs, as there has
been little investigation regarding the appropriate age or developmental stage to change
from equations traditionally used for children, to those for adults. The limited precision
of creatinine and cystatin C based estimation of GFR
in the normal ranges are
recognized. However, these methods may provide useful information on changes in GFR
which are predictive of important outcomes
(24)
.
5.1.8.
Markers of Macrovascular Disease: Vascular Dysfunction
While there is great concern regarding the extent to which diabetes mellitus increases
CVD risk, very little is known about the early stages of this process as they progress in
adolescents and young adults. Vascular dysfunction occurs early in the atherosclerotic
process and it is associated, among others,
with obesity, hypertension and insulin
resistance
(25)
. Since atherosclerosis is known to progress in a non-uniform fashion
throughout the vascular tree
(26)
, multiple methods have been developed to evaluate
vascular function non-invasively. Non-invasive methods to study vascular function
include, among others, assessment of arterial stiffness.
5.1.8.1.
Measurement of arterial stiffness
The SphygmoCor CPVH System from AtCor Medical (Lisle, IL) is a portable system
to measure arterial stiffness by pulse wave velocity (PWV), augmentation index (Aix)
by non-invasive arterial tonometry, and heart rate variability (HRV).
Section 5B - Data Collection (Phase 3 - 1/2011, rev. 8/2011)
Section 5B - Page 6
Cohort
Study
5.1.8.1.1.
Dostları ilə paylaş: