Requesting CKiD Data
To request CKiD data from the DCC, use the Data Request Form (will be posted soon).
Summary Files and Codebooks
Below are descriptions of some of the summary files that KIDMAC has developed for CKiD. A link to the codebook is also provided.
DATEBASE: An ID-visit file, which provides visit numbers, corresponding study dates and status of visit. The status of each visit (file record) is defined as one of the following: regular (occurring per study protocol), irregular (occurring on an accelerated schedule due to an anticipated transition to renal replacement therapy), disenrollment due to participant withdrawal, initiation of RRT, or death (documented via the disenrollment form), or phone-follow-up or in-person interview (non-clinical visit). VERT_DATEBASE Codebook
KIDHIST: A horizontally structured data file with one record for each participant. The file contains key clinical and date variables describing each participant's kidney disease history. Clinical variables include primary CKD diagnosis, current CKD status (no history of RRT, on dialysis, transplant recipient, and in rare cases, death), study status at last visit, and parametric estimates of each participant's baseline GFR and percentage change in GFR over follow-up. Date variables document the following occurrences: birth, study baseline, last date RRT free, first transplant, first dialysis, last date known alive (i.e., last contact date), and in rare cases, date of death. KIDHIST Codebook
GFR SUMMARY: An ID-visit file which provides a complete description of all variables related to both the measurement and estimation of each participant's glomerular filtration rates (GFR). This includes all variables related to the iohexol-infusion protocol (iGFR) as well as the biomarkers (serum creatinine, BUN and Cystatin C) that are used to estimate GFR (eGFR). GFRSUMMARY Codebook
CARDIO: An ID-visit file containing variables summarizing blood pressure variables from the clinic and ambulatory blood pressure monitoring protocol. Annual clinic BP measurements and biennial ABPM measurements are included. Working Group Clinic BP limits and Soergel ABPM limits according to age, sex and height are reported. Summary clinic BP measurements include SBP and DBP index (i.e. SBP/Limit based on age, sex and height), and z-scores and percentiles adjusted to age, sex and height. Summary ABPM variables include mean systolic and diastolic BP over 24 hour monitoring, load (i.e. % of readings that are over the 95% Soergel limit), dipping status and success rates. CARDIO Codebook
LABMARKERS: An ID-visit file containing variables for laboratory markers. The file includes basic metabolic panel, complete blood count, urine analysis, intact parathyroid, c-reactive protein, lipid panel and iron results as well as calculated proteinuria, acidosis, hypoalbuminemia, abnormal calcium and phosphate (based on KDOQI thresholds), calcium-phosphate product, elevated CRP, anemia and hemoglobin z-scores and percentiles based on age, sex and race per CDC guidelines.LABMARKERS Codebook
ECHO: An ID-visit dataset of summarized echocardiogram scans collected at biennial visits and sent from the CKiD ECHO lab (Cardiovascular Imaging Core Research Laboratory (CIRCL), Cincinnati, OH) to KIDMAC. Variables quantify the following clinical characteristics: left ventricular mass (LVM, including LVM index), left ventricular geometry, left ventricular hypertrophy, ascending aortic distensibility, ascending aortic stiffness, and shortening fraction abnormalities.ECHO Codebook
CIMT: An ID-visit file containing variables of measurement of the carotid artery, assessed using ultrasound, including carotid Intimal Medial Thickness (cIMT) and incremental elastic modulus or carotid artery pressure (EINC). By protocol, subjects have a cIMT ultrasound at every second visit (Visit 2, 4, 6, 8). This ultrasound is conducted on a subset of the CKiD population (n= 116 at visit 2). CIMT Codebook
NEURO: An ID-visit file containing key variables from the Neurocognitive battery, the Behavioral battery as well as the quality of life measurements. Key variables include: 1) Verbal IQ, Performance IQ and Full Scale IQ as measured by the Mullen, WPPSI-III or WASI; 2) scaled overall achievement score as measured by the WIAT-II-A; 3) scaled attention scores as measured by the K-CPT or CPT-II; 4) scaled executive functioning summary scores as measured by the BRIEF-P or BRIEF and 5) parent and child quality of life sub-scale and overall scores as measured by the PedsQL inventory. This is a vertical file with each record corresponding to one person-visit. Additional variables will be added as the need arises. NEURO Codebook
GROWTH: An ID-visit file, which contains key variables describing the growth markers (i.e., height, weight, tanner staging). Age and sex adjusted percentiles and z-scores are calculated based on CDC growth charts with normative data. Quantitative data on the participant's birth weight and gestational age, along with qualitative indicator variables for low birth weight (<2500 grams), premature birth (gestational age <36 weeks), small for gestational age (birth weight <10th percentile for gestational age), and intensive care unit immediately after delivery are also included. GROWTH Codebook
MED_SUM SHORT: The MEDSUM_SHORT is structured as one record per participant-visit and summarizes whether or not the study participant has been prescribed during the past 30 days any medication that falls into one of several major medication classes including antihypertensives, ESA's, growth hormones, immunosuppressives, anticholinergics, and antidepressants. MED_SUM SHORT Codebook
MED_SUM FULL: The MEDSUM_FULL contains one record per medication per participant-visit and provides more detailed information for the medication including dosing amounts and schedules as well as a set of variables that describe the participant's adherence to the medication. MED_SUM FULL Codebook