This study aimed to identify predictors of rapid progression of chronic kidney disease (CKD) using data from a large CKD clinic. The study found that lower initial systolic blood pressure, advanced age at the initial clinic visit, and longer duration of treatment at the clinic were associated with slower CKD progression. However, the study results contradicted previous findings that factors like proteinuria, ACE inhibitor use, diabetes, and initial anemia predict progression. The authors believe this may be due to survivor bias, as patients who died or started dialysis were not captured, and plan to re-examine the data to avoid this error.

1. Cohort Characteristics
Predictors of Progressive Versus Stable Chronic Kidney Disease
Gary G. Abud, Jr., Joel M. Topf, MD, Robert Provenzano, MD, FACP • St. John Hospital & Medical Center, Detroit, MI
Introduction
In previous studies of our
CKD population, we have
found a large variation in the
change in GFR over time
among different patients. This
is consistent with data
showing that only a minority of
patients with chronic kidney
disease progress to end-stage
renal disease. Despite this,
much of the focus of CKD
care is on preparing for
dialysis. Physicians need
reliable tools to predict which
patients will and will not
progress to dialysis.
Purpose
Determine factors which
predict accelerated rates of
CKD progression.
Methods
We used a database from a large, multi-center CKD clinic to identify predictors of rapid
progression of CKD.
All non-transplanted CKD patients in the clinic for at least one year and with at least four
visits were enrolled in the study. Each subject had a rate of progression calculated by
comparing the averages of the two most recent GFRs to the first two GFRs. Patients were
divided into quartiles based on the rate of progression and we compared patients in the 1st
quartile (fastest progression, loss of an average of 5 ml/min/yr) to the 4th quartile (slowest
rate of progression, gain of an average 1.9 mL/min/yr). Multivariate logistic regression was
performed to determine risk factors for rapid progression.
Discussion
Our data does not agree with much of the dogma on
chronic kidney disease:
• Proteinuria was protective rather than harmful
• Use of ACEi and ARB was not protective
• Diabetes was not harmful
• Anemia on the first visit not predictive of progression
This puts our methodology into question. We believe the
primary error in our study can be demonstrated in the
finding that with multivariate analysis, patients who had
higher clinic vintage had significantly more stable renal
function over time. This may reflect a survivor bias, since
patients who do not return to the CKD clinic (due to death
or dialysis) are not captured as progressing. We are re-
examining the cohort including the primary end-points of
death and dialysis to avoid this error.
Despite the primary weaknesses in the study design
there are two important findings that can guide
physicians to the future progression of renal failure:
1. Lower initial blood pressures predicted slower pro-
gression of renal disease. The SBP which was
associated with no GFR loss was 130.9 mmHg.
2. Age was a reliable factor that could be used as a
predictor of which patients are likely to progress to
ESRD. Age is one of four variables used in the stan-
dard MDRD equation. The finding that patients with
advanced age were less likely to have progressive
CKD may indicate that decreased GFR due to ad-
vanced age may not carry the same prognosis as
decreased GFR due to increased creatinine.
Conclusion
Many variables, e.g. race, DM and presence of
proteinuria, thought to be associated with rapid
progression of CKD were not helpful in predicting
rapid progression of CKD. However, other symptoms
of renal failure, such as high BP and anemia, were
predictive of rapid progression of CKD.
Stage 1
7%
Stage 2
13%
Stage 3
43%
Stage 4
30%
Stage 5
7%
Single Variable Analysis Association to CKD Significance
Urine Protein : Urine Creatinine (PCR) < 0.3 Faster Progression p = 0.009
Greater Clinic Vintage Slower Progression p = 0.01
Development of Anemia 2° CKD Faster Progression p < 0.0005
Multivariate Analysis Association to CKD Significance
Lower Systolic Blood Pressure on 1st
Clinic Visit Slower Progression p < 0.0005
Advanced Age on Initial Clinic Visit Slower Progression p = 0.009
Longer Duration of Treatment in Clinic Slower Progression p = 0.016
(100.00)
(80.00)
(60.00)
(40.00)
(20.00)
0.00
20.00
40.00
60.00
80.00
100.00
100 120 140 160 180 200 220 240
∆GFR(mL/min/yr)
Average of First Two Systolic Blood Pressures (mmHg)
Results
Factors not associated with rate of progression included:
 Age  Diabetes  Race  Use of ACEi at 1st Visit
 Anemia at 1st Visit  Initial GFR  Sex  Use of Vitamin D
 Change in Weight  LDL  Total Cholesterol  Weight
Patients in Cohort 712
Female 69%
African American 31%
Diabetic 43%
Average Age 62.4 ± 19.6
Age Range 18 - 95
Median Clinic Vintage 371 days
Quartile ∆GFR n
1st -5mL/min/yr 176
4th 1.9mL/min/yr 180