SDCC - Prospective Cohort Study of Chronic Renal Insufficiency

Insights into the cause of kidney failure have emerged from research, but less is known about the epidemiology of less severe forms of kidney disease known both as chronic kidney disease (CKD) or chronic renal insufficiency (CRI).

The Chronic Renal Insufficiency Cohort (CRIC) Study was established to study the consequences of CKD with a particular focus on cardiovascular illness like myocardial infarction (heart attack) and stroke. The CRIC Study will identify high-risk subgroups of individuals with CRI, informing future treatment trials, and development of preventive therapies.

CRIC is an observational study that to date, over 5000 participants have been enrolled in the CRIC cohort. The goal for CRIC 2018 which began in July 2018 is to follow participants for an additional 5 years. To maximize the opportunities inherent in this unique scientific resource, the CRIC Study will, in its next phase, pursue a multifaceted strategy involving: (a) continued follow-up of the cohort and investigation of a broad array of factors associated with the progression and consequences of CKD utilizing state-of-the-art methods in biostatistics and bioinformatics; and (b) the use of novel remote data collection techniques to identify trajectories of kidney function and cardiovascular risk sub-phenotypes.

Previously enrolled participants who reconsent to the next phase. CRIC 2018, will be enrolled in this observational study. Participants will remain under the care of their usual physicians. Questionnaires will be completed and tests will be conducted that will provide information about aspects of kidney and heart health status.

Participants who reconsent to this phase will return to the center for a more extensive visit. At the Clinic Visit the following will occur:

• weight is measured
• blood pressure and heart rate are recorded
• information about medical history and medication used recently
• blood draw (about ½ cup) for the following tests: CBC (Complete Blood Count), tests of metabolism, and several other heart and kidney tests
• blood pressure in the leg and arm calculated as the Ankle Brachial Index (ABI)
• urine sample collection for kidney function testing
• complete questionnaires about quality of life, diet, mood, thought processes and physical activity

This visit takes about 1 to 2 hours. Participants will be contacted by telephone six months after the Baseline Visit to ask about recent medical events and medications.

Participants will be asked to return to the center for annual visits during which many but not all of the procedures described above will be conducted.

Additionally, up to 1500 CRIC participants will be asked to participate in one of two substudies using remote data collection techniques to identify trajectories of kidney function and cardiovascular risk sub-phenotypes.

Trajectories of Kidney Function and Damage Sub-Protocol:

CRIC participants who are eligible and consent to participation in the Trajectories of Kidney Function and Damage Sub-Protocol will be asked to perform monthly fingerstick creatinine testing for 12 months. Participants will also quantify home albuminuria/proteinuria monthly during the same 12-month period using the combined technology of a urine diagnostic dipstick and scan card, and smartphone application. Research study staff will review the home test instructions for both procedures and conduct a practice run of the procedures with the participant to confirm the participant can master the procedures. Participants will be asked to test their urine on the same day as their fingerstick creatinine which will be listed on their personalized calendar, with the same reminder and resupply methods. Prior to testing their urine, participants will be asked to complete a brief survey on risk factors for AKI through the smartphone application.

CV Sub-Phenotyping Sub-Protocol

For CRIC participants who are eligible and consent to participation in the CV Sub-Phenotyping Sub-Protocol (up to 1500) will be fitted in person or remotely with the Zephyr BioPatch and instructed on how to care for it and recharge it. The Zephyr BioPatch consists of a sensor known as the BioModule, which contains a 3-axis accelerometer and a single-lead ECG (EC38 Type 3 ambulatory), sampled at 1KHz. It is powered by a rechargeable battery, with each charge lasting approximately 24 hours. The BioModule is worn using a disposable chest patch. Participants will be asked to wear the BioPatch for two consecutive 24-hour periods. Participants will recharge the BioPatch between these two 24-hour periods. Participants will then return the BioPatch to the clinical center.

To detect the occurrence and burden of atrial fibrillation and other atrial and ventricular dysrhythmias, the study team will fit participants with the ZIO XT Patch (iRhythm Technologies, http://www.irhythmtech.com/products-services/zio-xt), which provides for 14-day continuous, beat-to-beat ECG monitoring and validated arrhythmia detection algorithms. The general procedure for this component of the sub-protocol will be similar to that described for the Zephyr BioPatch. Up to 1500 eligible and willing participants will be fitted in person or remotely with the ZIO XT Patch at their first, second or third annual clinic visit during CRIC 2018. The ZIO XT Patch, which is typically worn on the upper left part of the chest, will be worn continuously for 14 days, after which the participant will mail the patch back to iRhythm Technologies for analysis and reporting back to the SDCC using a prepared mailer distributed to participant at the time patch is affixed.

Participants enrolled in the CV Sub-Phenotyping Sub-protocol may be asked to wear both the Zephyr Biopatch and the ZIO XT Patch at different timepoints but are not required.

Participation in the Trajectories of Kidney Function and Damage sub-protocol will not preclude participation in the CV sub-phenotyping sub-protocol.