CKD stage at nephrology referral and factors influencing the risks of ESRD and death.
BACKGROUND
Patients with chronic kidney disease (CKD) stages 3-5 are at increased risk of progressing to end-stage renal disease (ESRD) or dying prior to the development of ESRD compared with patients with less severe CKD. The magnitude of these risks may vary by stage, which has important implications for therapy. Our objective was to apply a competing risk analysis in order to estimate these risks in a referred cohort of patients with CKD by stage at referral and identify risk factors associated with each outcome.


METHODS
Retrospective cohort study.


METHODS
3,273 patients with CKD stages 3-5 who were referred to the nephrology clinic at Sunnybrook Health Sciences Centre, Toronto, prior to December 31, 2008, with follow-up data available prior to December 31,2008.


METHODS
CKD stage at time of referral; demographic, laboratory, and clinical characteristics.


RESULTS
ESRD, defined as the initiation of dialysis therapy or pre-emptive kidney transplantation, and death from any cause prior to ESRD.


METHODS
Baseline laboratory data.


RESULTS
Over a median follow-up of 2.98 years, 459 patients (14%) developed ESRD and 540 (16%) died. Rates per 100 patient-years of ESRD versus death prior to ESRD for CKD stage 3A were 0.6 (95% CI, 0.1-1.0) versus 2.2 (95% CI, 1.2-3.1; P<0.001); for CKD stage 3B, 1.4 (95% CI, 0.8-2.1) versus 4.4 (95% CI, 3.3-5.6; P<0.001); for CKD stage 4, 7.7 (95% CI, 5.9-9.4) versus 8.0 (95% CI, 6.2-9.8; P=0.6); and for CKD stage 5, 41.4 (95% CI, 34.4-48.4) versus 9.4 (95% CI, 5.2-13.4; P<0.001). For those with CKD stage 4, we identified 12 variables associated with higher risk of ESRD and 7 variables associated with higher risk of death prior to ESRD.


CONCLUSIONS
A cohort analyzed retrospectively.


CONCLUSIONS
ESRD and death prior to ESRD incidence was most similar in CKD stage 4. We identified variables easily assessed at the time of referral that could discriminate between these risks.
Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
Maneesh
M
Sud
Division of Nephrology, Seven Oaks General Hospital, University of Manitoba, Winnipeg, Manitoba, Canada.
Navdeep
N
Tangri
Division of Nephrology, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada.
Adeera
A
Levin
Department of Biostatistics, University Health Network, Toronto, Ontario, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
Melania
M
Pintilie
Division of Nephrology, Tufts Medical Center, Boston, MA.
Andrew S
AS
Levey
Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Division of Nephrology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada; Institute of Health Policy Management and Evaluation, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada. Electronic address: david.naimark@sunnybrook.ca.
David M
DM
Naimark
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000453:epidemiology* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009398:Nephrology; D012017:Referral and Consultation; D051436:Renal Insufficiency, Chronic / Q000473:pathology; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D055815:Young Adult
Chronic kidney disease; end-stage renal disease; epidemiology; mortality