ProtocoL for GFR Measurement Using Iohexol (SCOPE-PLUS) - A Substudy of the SCOPE Study

SCOPE-PLUS is an optional substudy of the SCOPE cohort study (Screening for Chronic Kidney Disease among Older People across Europe, NCT02691546). SCOPE has retrieved data on a wide panel of biomarkers of CKD in a large study cohort enrolling about 2,450 older people in Italy, Spain, Germany, Austria, Netherlands, Poland and Israel. The innovative biomarkers have been already validated by the literature, and include e.g. Cystatin C (CysC), β-Trace protein (BTP), and Beta2-microglobulin. Others promising novel biomarkers of CKD, based on metabolomic and proteomic determinations or other techniques have been evaluated. The objective of the SCOPE-plus study is to to verify the accuracy of newly developed equations based on innovative and novel biomarkers of CKD function by calculating the percentage of estimates within 30% (P30) of the measured GFR (mGFR). The mGFR will be obtained by the assessment of nonradioactive iohexol clearance. Patients previously enrolled in the SCOPE study, are invited to participate in this additional protocol. Iohexol is an iodinated contrast medium with characteristics similar to those of inulin, being freely filtered by the glomerulus, neither secreted nor reabsorbed by the renal tubules and recovered almost 100% in the urine. These characteristics made it an ideal agent for the determination of the renal function.