Ascertaining Clinical Endpoints in Epidemiological Research: Findings from the Chronic Renal Insuffi

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Ascertaining Clinical Endpoints in
Epidemiological Research Findings from the
Chronic Renal Insufficiency Cohort (CRIC) Study
Nessel L, Hyre AD, Messé SR, Kimmel S, Kasner
SE, Mohler ER, Prineas R, Vaitkus P, Feldman HI,
and the CRIC Study Investigators.
Preliminary Study Data
Background
Clinical Endpoint Ascertainment Process
Table 2 Preliminary self-reported
hospitalization data from CRIC Study participants
Chronic renal insufficiency (CRI) is recognized
as a silent epidemic impacting over 15 million US
adults the burden of morbidity and mortality
associated with CRI derives from its frequent
progression toward end-stage renal disease (ESRD)
and the disproportionate risk of cardiovascular
(CV) disease in this setting.

• Key personnel clinical site event coordinators,
  Clinical Endpoint Center (CEC) staff, nurse
  abstractors, adjudication committee
  (cardiologists, neurologists, nephrologists)
• A rigorous, tailored process for evaluating all
  morbidity requiring hospitalization and for CV,
  peripheral vascular, cerebrovascular, renal, and
  death events
• Built on the foundation of successful national
  CV cohort studies
• Begins with biannual queries of subjects
  regarding any symptoms suggestive of CRIC
  clinical outcomes, hospitalization, selected
  outpatient procedures and diagnoses
• Includes collection of all hospital
  administrative code data, targeted portions of
  medical records for evaluation of primary CRIC
  outcomes, and death certificates
• Specific ICD-9 and procedure codes pre-defined
  as triggers for clinical endpoint adjudication
• Renal events are not adjudicated as they are
  based on calculated measures of renal function
  and dialysis records

Objective
To describe the methods for ascertaining clinical
endpoints and to report preliminary self-reported
hospitalization data from the CRIC Study.
Methods
Prospective cohort study with 3,612 individuals
who will have up to 10 years of follow-up at
seven clinical centers. Table 1 CRIC Cohort
Composition
Data are not yet complete and include those
collected through 9/2008. CAD coronary
artery disease HF heart failure, PAD
peripheral artery disease
Figure 1 Clinical Endpoint Adjudication Process
Conclusions

• Ascertainment of clinical endpoints in CRIC, a
  large, multi-center epidemiological study,
  requires efficient acquisition of hospitalization
  records and rigorously standardized procedures to
  accommodate the large number of hospitalizations
  experienced by this CRI cohort.
• The high incidence of self-reported
  hospitalizations reflect much morbidity at
  baseline and throughout follow-up.
• These data suggest that the rate of CV events
  among CRIC participants will be quite high.
• Collection of administrative hospital codes for
  all hospitalizations provides opportunities for
  preliminary assessment of endpoints beyond the
  CRIC clinical endpoints.

Clinical Endpoints

• Renal estimated glomerular filtration rate
  (eGFR) slope, onset of ESRD, 50 decline in eGFR,
  slope of change in proteinuria, doubling of serum
  creatinine
• Cardiovascular myocardial infarction,
  hospitalization for heart failure, serious
  cardiac arrhythmia
• Peripheral vascular amputation for peripheral
  artery disease (PAD), surgical or percutaneous
  revascularization for PAD
• Cerebrovascular cerebral infarction,
  intraparenchymal or subarachnoid hemorrhage
• Death due to atherosclerotic coronary heart
  disease, cerebrovascular disease, other
  atherosclerotic disease, other CV disease, and
  other causes

Acknowledgements The authors would like to thank
Jennifer Dickson and Elizabeth Helker for their
contributions to this work. This work was
supported through NIH Grant U01-DK060990. For
more information, please visit the CRIC Study
website at www.cristudy.org