Topic: Renal and Urogenital
Conditions
Interventions
Main study: 1300 patients. Biological variability study: In a sub-study 20 participants will undergo the reference test four times over four weeks and then exit the study.
Iohexol GFR tests, 1300 par
Sponsors
University of Birmingham (UK)
Eligibility
Sex/Gender
All
Age
18 Years to 100 Years
Inclusion criteria
Inclusion criteria: 1. Male and female, aged 18 years or over 2. Patients with stage 3 CKD (GFR 30-59 mL/min/1.73 m2) as defined internationally, diagnosed using Modification of Diet in Renal Disease/Chronic Kidney Disease Epidemiology Collaboration (MDRD/CKD EPI) eGFR (at least two consecutive test results in this range at least 90 days apart, with the most recent test in the last 12 months) 3. Written informed consent
Exclusion criteria
Exclusion criteria: 1. History of untoward reactions to iodinated contrast media or allergy to topical iodine 2. Episode of acute kidney injury in previous 6 months (as defined by the Acute Kidney Injury Network criteria) 3. Amputation of whole or part limb 4. Pregnant or breastfeeding 5. Known alcohol or drug abuse 6. Any clinical condition with an expected survival of less than study duration 7. Inability to comply with study schedule and follow-up 8. Inability to provide informed consent e.g. due to cognitive impairment
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. To estimate and compare the accuracy and precision of GFR-estimating equations based on the Modification of Diet in Renal Disease (MDRD) equation and three Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations using either creatinine or cystatin C or a combination of both in people with stage 3 CKD. 2. To estimate the accuracy and precision of the GFR-estimating equations according to ethnic group (particularly Caucasians, African-Caribbean and South-Asian), and baseline diabetes and proteinuria. Percentage error in eGFR compared to reference GFR. Values will be computed (primary outcome measures 1 and 2) using baseline data for each of the four eGFR equations, and the proportions within 30% (P30) of the reference standard quoted and compared as a measure of accuracy and precision. 3. To evaluate and compare how accurately these GFR-estimating equations reflect change in GFR over three years. Difference in rate of change in eGFR compared to rate of change in reference GFR. Rates of change will be estimated using linear regression and the change per annum and percentage change per annum compared to baseline values will be computed. Large error will be defined as differing by more than 3 mL/min/1.73 m^2/year or by 5 percent points per annum. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. To establish which GFR-estimating equation, together with ACR, or ACR alone, most accurately predicts those people that have progressive loss of kidney function (CKD progression). Progressive loss of kidney function defined as decline in GFR of more than 10 mL/min/1.73 m^2/3 years or increase in albuminuria category as defined by Kidney Disease: Improving Global Outcomes (KDIGO). 2. To compare the effectiveness and costs of monitoring strategies for identifying people that have progressive loss of kidney function (CKD progression) utilising different GFR-estimating equations and test schedules, accounting for differences in risk of progression. Measured using Cost per quality-adjusted life-year (QALY). Sub-study of patterns of disease progression To estimate and model disease progression (decline in GFR or increase in ACR) according to ethnic group (particularly Caucasians, African-Caribbean and South-Asian), and baseline diabetes and proteinuria. Difference in rate of change in eGFR compared to rate of change in reference GFR based on measurements made every 12 months. Additional study of intra-individual biological variation Within-individual (CVI) variation and the critical difference (reference change value, RCV) for reference GFR and the estimated GFR equations. | — |
Countries
England, United Kingdom
Outcome results
None listed