Sir Seewoosagur Ramgoolam National Hospital
Keeping up with
CKD
Davy Ip
Keeping up with
CKD
Davy Ip
Why eGFR?
Why CKD?
Proteinuria and haematuria
CKD guidelines
CKD caveats
Reports that say that something hasn't happened are always
interesting to me, because as we know, there are known knowns;
there are things we know we know. We also know there are known
unknowns; that is to say we know there are some things we do not
know. But there are also unknown unknowns - the ones we don't
know we don't know
Why eGFR?
Why use eGFR ?
To estimate renal function
Functions of the kidney
Homeotasis
Fluid, electrolytes and
acid base balance
Excretion of metabolites
Organic acids
Phosphates
Urea / creatinine etc
Hormone production
Renin / angiotensin
Vit D metabolites
Erythropoietin
GFR is usually accepted as the best overall index
of kidney function in health and disease.
GFR cannot be measured directly
CAPILLARY
WALL
BLOOD
GLOMERULAR
BASEMENT
MEMBRANE
URINE
URINARY
EPITHELIUM
Glomerular filtration
Capillary
Net glomerular
filtration pressure
wall
=
URINE
BLOOD
Hydrostatic pressure – oncotic
pressure – capsular pressure
GLOMERULAR
BASEMENT
MEMBRANE
Urinary
epithelium
Glomerular filtration rate
The renal clearance of any substance
is
the volume of plasma
that can be completely cleared by the kidney
in unit time
or
urine concn. x urine flow rate
plasma concentration
Glomerular function rate
Sum of all nephron filtration rates
a measurement of excretory kidney function
Normal GFR varies according to age, sex, and body size;
In young adults it is approximately 120-130 ml/min/1.73 m2
and declines with age.
Reduction implies a problem
The Gold Standard
The ideal marker.
If a substance in stable concentration in the plasma is
physiologically inert, freely filtered at the glomerulus, and
neither secreted, reabsorbed, synthesized, nor metabolized
by the kidney, the amount of that substance filtered at the
glomerulus is equal to the amount excreted in the urine.
Inulin satisfies all the properties of an ideal marker and is
the gold standard for the measurement of GFR.
Inulin clearance = GFR = UV/P
Urea
The majority of nitrogen from the
breakdown of dietary or body
proteins is excreted as urea in the
urine.
Nitrogenous waste goes to the
liver as NH4+. The liver removes
the toxic NH4+ and produces
urea.
Urea case 1
A 68 year old man presents to the hospital feeling unwell. He
is very tired and feels ‘fluish’. He has been diagnosed with
lymphoma a month ago after presenting with marked
widespread lymphadenopathy. He has a course of
chemotherapy and is still taking prednisolone 30mg daily.
His GP has prescribed oxytetracycline for an acneiform rash.
He complains that his stools seem to be much darker and
loose.His U+Es are as follows:
Na+ 138
K+ 4.7
Urea 26
Creatinine 110
Explain these figures.
Urea case 2
A 31 year old woman presents to the hospital feeling unwell
and with abdominal distension. She is known to have an
alcohol problem, she admits to have drunk heavily on and
off since her teenage years. On examination, though her
face and limbs look emaciated, she has a distended
abdomen. Her blood results are as follows.
Na+ 138
K+ 4.7
Urea 2.6
Creatinine 70
Explain these figures.
Far from ideal: urea
PRODUCTION
ELIMINATION
Dietary protein
GI bleed
Renal disease
Increased catabolism
Surgery
Infection
Trauma
Cancer/ tumour lysis syndrome
Drugs
Corticosteroids
Tetracyclines
Deceased metabolism
Old age
Protein
Amino Acids
pool
Pre-renal failure causes a disproportionately high urea due to the need
to conserve water compared to
intrinsic and post-renal kidney failure
GFR increased in pregnancy
Liver
Blood
Urea
Liver failure
Urine
Urea
Creatinine
Derived mainly from muscle metabolism,
proportional to muscle mass, and is virtually all
excreted by the kidneys.
Usually produced at a more steady rate for a
given individual compared to urea.
Easy to measure.
Creatinine
Creatinine - Problems
Serum creatinine (umol/L)
1000
900
800
700
600
500
400
300
200
100
0
0
10
20 30
40
50
60
70
80 90 100 110 120
GFR (Inulin clearance, ml/min/1.73m2)
Not a sensitive marker for changes in GFR when renal function is or is normal.
Indeed, people may lose 50% of normal GFR and have a borderline high GFR.
Use of creatinine as an index of GFR
rests on 3 major faulty assumptions:
(1) creatinine is an ideal filtration marker whose clearance approximates GFR
Tubular secretion
Proportionately more important in advanced CKD
Blocked by commonly used medications
Extra-renal creatinine excretion
Minimal in people with normal renal function but increased in
patients with CKD
Use of creatinine as an index of GFR
rests on 3 major faulty assumptions:
(2) creatinine production is constant among individuals and over time
Factors affecting muscle mass
Age
Female Sex
Afro-Caribbean race
Muscular
Malnutrition/ muscle wasting/ amputation
Obesity
Diet and drugs
Vegetarian diet vs Meat diet
Trimethoprim, cimetidine reduce tubular secretion of creatinine
Effect of Muscle Mass on Serum Creatinine
Normal
Muscle
Mass
Normal
Muscle
Mass
Increased
Muscle
Mass
Reduced
Muscle
Mass
Creatinine
Input
Plasma
Pool
Content
Output
Kidney
Normal
Kidneys
Diseased
Kidneys
Normal
Kidneys
Diseased
Kidneys
32yr old
55yr old
70kg
26yr old
26yr old
55yr old
84yr old
48kg
70kg
96kg
99kg
70kg
These people all have a creatinine of 136 micromol/l
and urea of 5 mmol/l.
Please order in terms of GFR!
32yr old
26yr old
26yr old
55yr old
55yr old
70kg
84yr old
48kg
70kg
96kg
99kg
70kg
32yr old
26yr old
26yr old
55yr old
55yr old
70kg
84yr old
48kg
70kg
96kg
99kg
70kg
26yr old
96kg
32yr old
84yr old
48kg
55yr old
70kg
55yr old
70kg
70kg
26yr old
99kg
26yr old
96kg
32yr old
84yr old
48kg
55yr old
70kg
26yr old
55yr old
70kg
70kg
99kg
Beware of serum creatinine interpretation
84yr old
48kg
55yr old
70kg
32yr old
26yr old
70kg
99kg
26yr old
55yr old
70kg
96kg
Beware of
serum
creatinine
interpretation
Audrey
Audley
CCl
80-120ml/min
CCl
80-120ml/min
Creatinine
67-45 mol/l
Creatinine
190-126mol/l
Use of creatinine as an index of GFR
rests on 3 major faulty assumptions:
(2) creatinine production is constant among individuals and over time
Factors affecting muscle mass
Age
Female Sex
Afro-Caribbean race
Muscular
Malnutrition/ muscle wasting/ amputation
Obesity
Diet and drugs
Vegetarian diet vs Meat diet
Trimethoprim, cimetidine reduce tubular secretion of creatinine
Use of creatinine as an index of GFR
rests on 3 major faulty assumptions:
(3) measurement of creatinine is accurate and reproducible across clinical laboratories.
It was not so until the last few years because of different assays for creatinine used,
some of them interfered with b drugs eg cephalosporins
Creatinine - Problems
Summary
Not linear relationship with renal function
Poorly sensitive in early CKD and near normal renal function
Overestimation of renal function in advanced CKD
Affected by muscle mass – age /sex/ race
– abnormal body habitus
Laboratory assays give differing results
Improving on creatinine
Serum creatinine (umol/L)
1000
900
800
700
600
500
400
300
200
100
0
0
10
20 30
40
50
60
70
80 90 100 110 120
GFR (Inulin clearance, ml/min/1.73m2)
Alternative markers
125I-iothalamate
99mTc-DTPA
Iohexol
51Cr-EDTA
Serum cystatin C
Creatinine clearance
The previously commonly used estimate of GFR.
Patient has to do a 24 hour urine collection and a blood
test within hours of finishing the collection.
Creatinine clearance
Problems:
Poor patient compliance, unreliable
A small amount of creatinine is secreted by the
tubules leading to overestimation of GFR,
particularly at low GFR
Prediction equations to estimate GFR
Cockcroft-Gault equation
CrCl in ml/min
=
[(140 - age) x weight (kg)]/SCr x 72 (x0.85 if female)
Cockcroft DW, Gault MH: Prediction of creatinine clearance from serum creatinine. Nephron 16:31-41, 1976
MDRD equation
GFR in ml/min/1.73m2
=
186
x (serum creatinine in µmol/L x 0.011312)-1.154
x (Age)-0.203
x (1.212 if Black)
x (0.742 if female)
Levey AS, Greene T, Kusek JW, Beck GJ: A simplified equation to predict glomerular filtration rate from serum creatinine.
J Am Soc Nephrol 11:A0828, 2000
MDRD equation
On average, GFR estimated from the MDRD Study
equation is more accurate than measured creatinine
clearance or creatinine clearance estimated from the
Cockcroft-Gault equation in patients with reduced GFR
Levey, A, Bosch, J, Lewis, JB, Greene, T, Rogers, N, Roth, D. A more accurate method to estimate
glomerular filtration rate from serum creatinine: A new prediction equation. Ann Intern Med. 1999.
130: p. 461-470
MDRD equation
Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D: A more accurate method to estimate glomerular filtration rate from
serum creatinine: A new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 130:461-470, 1999
MDRD equation
Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D: A more accurate method to estimate glomerular filtration rate from
serum creatinine: A new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 130:461-470, 1999
MDRD equation - limitations
Use of the MDRD Study equation, or any other
equation, without re-calibration of serum creatinine assay
to the assay used in the laboratory in which the equation
was developed can introduce a systematic error into GFR
estimates. This error is greater at low serum creatinine
values.
MDRD equation - limitations
Validated in
Caucasians with with chronic kidney disease (mean GFR
40ml/min/1.73 m2) including diabetic kidney disease, kidney transplant
recipients, and African Americans with non-diabetic kidney disease.
Not validated in
children (age <18 years), pregnant women, the elderly (age >70 years),
racial or ethnic subgroups other than Caucasians and African
Americans, in individuals with normal kidney function who are at
increased risk for CKD, or in normal individuals.
MDRD equation - limitations
Furthermore any of the limitations with the
use of serum creatinine as related to
nutritional status, unusual body habitus
medication usage are not accounted for in
the MDRD Study equation.
Not applicable to situations with rapidly
changing serum creatinine e.g ARF
MDRD equation - BSA
Correction for body surface area
GFR varies with body size, usually expressed as BSA,
which can be estimated from height and weight.
Body surface area of 1.73 m2 is the normal mean value for
young adults.
Adjustment for body surface area is needed for meaningful
comparing a patient’s estimated GFR to normal values, or
to the levels defining the stages of CKD.
However, drug dosing should not used eGFR corrected for 1.73 m2
MDRD equation: changes to come?
CKD-EPI
A new equation with the same input parameters as the MDRD equation
Proposed to reduce the underestimation of GFR with people with near
normal renal function
The issue of ethnicity correction
Black-American vs Black African
South Asian vs East Asian
Chinese vs Japanese
Assume creatinine 136, urea 5, 1.73m2
Estimated creatinine clearance
21
46
50
68
76102
56
56
56
56
68
99
MDRD equation
34
37
MDRD equation with BSA
34
37
59
factored in
50 48
59
Assume creatinine 136, urea 5, 1.73m2
Cockcroft-Gault
21
46
50
68
76102
56
56
56
56
68
99
MDRD equation
34
37
MDRD equation with BSA
34
37
59
factored in
50 48
59
DO NOT USE
eGFR TO
CALCULATE
DRUG DOSES!
MDRD equation
34
37
56
56
56
59
Assume creatinine 136, urea 5
84yr old
48kg
55yr old
70kg
32yr old
26yr old
70kg
99kg
26yr old
55yr old
70kg
96kg
Assume creatinine 136, urea 5
Estimated creatinine clearance
21
84yr old
48kg
46
55yr old
70kg
54
68
102
32yr old
26yr old
70kg
99kg
99
26yr old
55yr old
70kg
96kg
Assume creatinine 136, urea 5
Estimated creatinine clearance
21
46
54
68
102
99
50
56
59
59
MDRD equation
34
84yr old
48kg
37
55yr old
70kg
32yr old
26yr old
70kg
99kg
26yr old
55yr old
70kg
96kg
Assume creatinine 136, urea 5
Estimated creatinine clearance
21
46
54
68
102
99
50
56
59
59
MDRD equation
34
84yr old
48kg
37
55yr old
70kg
32yr old
26yr old
70kg
99kg
26yr old
55yr old
70kg
96kg
Role of 24-hour urine collections
•
•
•
•
•
•
•
•
•
Extremes of age and body size
Severe malnutrition or obesity
Disease of skeletal muscle
Paraplegia or quadriplegia
Vegetarian diet
Rapidly changing kidney function
Prior to dosing drugs with significant toxicity that
are excreted by the kidneys
Pregnancy
Creatinine - Problems
C-G
Not linear relationship with renal function
Poorly sensitive near normal renal function
Overestimation of renal function in advanced CKD
Affected by muscle mass – age /sex/ race
Affected by muscle mass – abnormal body habitus
Laboratory assays give differing results
Poor collection
Correction for BSA, not ‘real’
Large margin of error at near normal renal function
MDRD
Measurement of renal function
Inulin/ Iohexol/ Iothalamate
Accurate
Isotopes- radioactive
MDRD eGFR
Cockcroft-Gault creatinine clearance
24hr urine collection creatinine clearance
Serum creatinine
Serum urea
Urine volume/appearance
Inaccurate
Proteinuria and haematuria
“Acceptable” proteinuria
Does normal urine contain protein?
< 150 mg/24 hours or PCR< 15mg/mmol
Orthostatic proteinuria
Low grade proteinuria of PCR<100 in children and young adults.
Diagnosis made when absent in early morning specimen.
Mechanism unclear but good prognosis
Transient/ haemodynamic proteinuria
Fever/ Exercise/ Heart failure/ Hyperadrenergic state
Benign prognosis
More confounding factors
Biological variation (day-to-day CV 45%)
Haematuria/menstrual contamination
Uncontrolled hypertension
Urinary tract infection
Pathological proteinuria
Fixed or persistent
Glomerular diseases
Increased glomerulus permeability to protein
Tubulointerstitial diseases
Decreased tubular reabsorption of protein
Overflow Causes – paraproteinaemia (myeloma, primary amyloid)
Increased low molecular weight protein production
Detecting and Quantifying
Proteinuria
Reagent strip tests
24 hour urine
Spot urine tests
Urine protein electrophoresis
Urinary protein or albumin/creatinine ratios
(PCR/ACR)
Dipstick proteinuria
150mg/l
300mg/l
Pitfalls of urine dipstick
Semiquantitive
More sensitive to albumin than other proteins
Does not often detect urinary light chains (Bence-Jones protein)
Does not detect microalbuminuria
False positive with alkaline urine (as in UTI) and some drugs
False negative with very acid urine and some drugs
Affected by urine concentration
Assuming 1-1.5l
uniform urine output
Normal
LOW
ACR PCR 24hrP 24hrA
mg/mmol mg/24hr
3
Microalbuminuria
if diabetic
Proteinuria
as defined by
CKD guidelines
Severe proteinuria
Nephrotic range
DIPSTICK -ve
Trace
+
30
15
150
30
50
500
70
100
1000
300
3000
++
DIPSTICK +ve
+++
HIGH
300
Total Protein Versus Albumin
Nephrology literature based on total protein, DM literature
defined by albuminuria
Proteinuria is predominantly albumin but
150 mg/L TP contains 30 mg/L albumin
300 mg/L TP contains 150 mg/L albumin
1000 mg/L TP contains 700 mg/L albumin
UK CKD recommend albumin in diabetes and total protein
or albumin in non-diabetic setting, on basis of cost
Total protein costs £0.10
Albumin costs £0.50
Microalbuminuria
Sensitive immunoassays can detect increased albumin in
urine before clinical (dipstick) proteinuria is detectable
It is common in diabetes mellitus and predicts progression
to ESRD and vascular complications
Early detection enables intervention to slow progression
Microalbuminuria and
diabetic nephropathy (DN)
Pre DN
Early DN
Overt DN
ESRF
GFR 100 ml/min
GFR
Albuminuria
0
5
MICROALBUMINURIA RANGE
15
25 years
Approach to Patient with Proteinuria
before Sept 2008
• If dipstick negative for proteinuria and
patient has diabetes then send urine for
ACR as per diabetes guidelines
• If dipstick positive for proteinuria send
urine for PCR in non-diabetics
Approach to Patient with Proteinuria
after Sept 2008
To detect and identify proteinuria, use urine ACR in
preference, as it has greater sensitivity than PCR
for low levels of proteinuria.
For quantification and monitoring of proteinuria,
PCR can be used as an alternative.
ACR is the recommended method for people with
diabetes.
Early identification and management
of chronic kidney disease in adults in
primary and secondary care
http://www.nice.org.uk/CG73
Haematuria
When testing for the presence of haematuria, use reagent strips
rather than urine microscopy.
Evaluate further if there is a result of 1+ or more.
Do not use urine microscopy to confirm a positive result.
When there is the need to differentiate persistent invisible
haematuria in the absence of proteinuria from transient
haematuria, regard two out of three positive reagent strip tests as
confirmation of persistent invisible haematuria.
Haematuria
Confounding factors
Can be renal or lower urinary tract in origin
Menstrual bleeding
Urine dipstick – false positive for myoglobinuria and
haemoglobinuria
Haematuria
Referral and follow-up
Persistent invisible haematuria, with or without proteinuria,
should prompt investigation for urinary tract malignancy in
appropriate age groups.
Persistent invisible haematuria in the absence of proteinuria
should be followed up annually with repeat testing for
haematuria, proteinuria/albuminuria (see recommendations
above), GFR and blood pressure monitoring as long as the
haematuria persists.
Testing kidney function: summary
Request and look at eGFR as well as serum creatinine and urea.
Correct for ethnicity: multiply eGFR by 1.21 for African-Caribbean or African
ethnicity.
Where a highly accurate measure of GFR is required – for example, during
monitoring of chemotherapy – use a gold standard measure.
Interpret eGFR with caution for people with extremes of muscle mass.
Make an allowance for biological and analytical variability of serum creatinine
(± 5%) when interpreting changes in eGFR.
When to test for CKD
Blood test for eGFR and creatinine
Urine for dipstick for ACR
Early morning
No meat in the last 12 hours
No recent heavy exercise
No recent trauma
Send blood and urine samples early enough to
allow analysis within 12 hours of sampling
Renal Ultrasound
Offer a renal ultrasound to all people with CKD who:
•have progressive CKD (eGFR decline more than 5 ml/min/1.73 m2
within 1 year, or more than 10 ml/min/1.73 m2 within 5 years)
•have visible or persistent invisible haematuria
•have symptoms of urinary tract obstruction
•have a family history of polycystic kidney disease and are aged over
20
•have stage 4 or 5 CKD
•are considered by a nephrologist to require a renal biopsy.
Advise people with a family history of inherited kidney disease about
the implications of an abnormal result before a renal ultrasound scan
is arranged for them.
Progressive CKD
Define progression as a decline in eGFR of > 5 ml/min/1.73 m2
within 1 year, or > 10 ml/min/1.73 m2 within 5 years.
– Take at least 3 eGFRs over at least 90 days.
– For a new finding of reduced eGFR, repeat test within 2 weeks to
exclude acute kidney injury (acute renal failure).
Consider whether the progression continuing at the observed rate
would mean renal
replacement therapy within the person’s lifetime.
Chronic use of NSAIDs may be associated with progression;
exercise caution and monitor GFR.
Why CKD?
Incidence Rate for RRT in the UK: 1980-2004
Mortality in HD Patients
Annual Mortality (%)
100
10
Dialysis Male
1
Dialysis Female
Healthy Male
0.1
Healthy Female
0.01
25-34
35-44
45-54
55-64
65-74
75-84
>85
Age (years)
Foley AJKD 1998
The
Nephrologist
CMO highlights CKD
PAGES 12 AND 32
Walsgrave’s transplant success
PAGES 13 AND 38
The future of haemodialysis
PAGES 16 AND 42
A SURVEY OF SALT
AFTER PAGE 56
Patients with CKD are more likely to die
than require dialysis
STAGE
GFR
RRT
Death
2
60-89
1.1%
19.5%
3
30-59
1.3%
24.3%
4
15-29
19.9%
45.7%
Keith, AIM 2004
Progression of kidney disease
Normal
kidney
Renal scarring
Endstage
kidney
The Cardiovascular Continuum
Tissue Injury
Vascular
Disease
Endothelial
Dysfunction
Risk Factors
Adapted from Dzau,1991
Pathological
Remodeling
Target Organ
Dysfunction
End-stage
Organ Failure
Death
Mortality in CKD: USA
• Health care system,
• 35% of local population,
• at least one serum creatinine
• > 1,2Mio adults
• > 20y of age
• Excluded at entry: ESRF, renal transplant
• MDRD: eGFR
Go A S et al. NEJM 2004
Cardiovascular Events
From Any Cause
(per 100 person-year)
Of Cardiovascular Events
(per 100 person-year)
Any Cause
Estimated GFR (ml/min/1.73m2)
1,120,295 Ambulatory Adults
Estimated GFR (ml/min/1.73m2)
of Hospitalization
(per 100 person-year)
Age-Standardized Rate
Hospitalization
Estimated GFR (ml/min/1.73m2)
Complications of CKD
KIDNEY DAMAGE
Hypertension
more frequent
than amongst
patients without
CKD
Mild elevation of
PTH
Hypertension
common
Altered lipid
metabolism
↓ spontaneous
protein intake
↓ PO4 excretion
↓ Ca absorption
Marked PTH rise
Renal anaemia
LVH
STAGE 1
STAGE 2
STAGE 3
STAGE 4
STAGE 5
Kidney Damage
with Normal or
↑ Kidney Function
Kidney Damage
with Mild
↓ Kidney Function
Moderate
↓ Kidney Function
Severe
↓ Kidney Function
Kidney failure
Persistent microalbuminuria
Persistent proteinuria
Persistent haematuria
Structural abnormalities of the kidneys
Biopsy-proven chronic glom’nephritis
GFR mL/min/1.73 m2
Hypertension
frequent
90
60
30
As Stage 3 but
more pronounced
&
Metabolic
acidosis
Hyperkalaemia
↓ libido
As stage 4(with
greater severity)
&
Salt and water
retention causing
apparent heart
failure
Anorexia
Vomiting
Pruritus
15
0
Classification of CKD <2008
Other evidence of kidney damage
Persistent diabetic microalbuminuria ACR >3*
Persistent proteinuria ACR>30
Persistent haematuria after exclusion of other causes
Structural abnormalities of the kidneys shown by radiology
Biopsy proven glomerulonephritis
National Kidney Federation, K/DOQI guidelines for CKD AJKD 2002
Classification of CKD >2008
The CKD guidelines
What are they?
CKD
Issued April 2006
Chronic Kidney Disease
Guidelines for adults
Department of Nephrology
Early recognition of CKD offers the chance
to reduce progression and associated
cardiovascular complications.
This document gives guidance on
screening, classification and management
of CKD in primary care as well as advice
on how and when to refer to the
nephrologist.
CKD challenges
7
Stage 5
GFR 15-29
16
Stage 4
GFR 30-59
98
Stage 3
GFR <15
GFR 60-89
? Stage 2
879
GFR >90
CKD:
? Stage 1
a typical GP practice of 1000
GFR and age
GFR and age
GFR and age
140
Mean Cov
Mean-1sd
Mean-2sd
eGFR (ml/min/1.73 m2)
120
100
80
60
Stage 3a
40
Stage 3b
Stage 4
20
Stage 5
0
20-34
35-44
45-54
55-64
65-74
Age bands
75-84
85+
CKD and age
70
• Age 40-49 years
60
• Age 60-69 years
– 5200 pmp
• Age ≥ 80 years
% Known
– 1000 pmp
50
40
30
20
10
0
– 60,000 pmp
< 50 50-59 60-69 70-79 > 80
Age
Pitfalls in young patients with CKD
Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D: A more accurate method to estimate glomerular filtration rate from
serum creatinine: A new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 130:461-470, 1999
Pitfalls in young patients with CKD
Serum creatinine (umol/L)
1000
900
800
700
600
500
400
300
200
100
0
0
10
20 30
40
50
60
70
80 90 100 110 120
GFR (Inulin clearance, ml/min/1.73m2)
Not a sensitive marker for changes in GFR when renal function is or is normal.
Indeed, people may lose 50% of normal GFR and have a borderline high GFR.
Pitfalls in young patients with CKD
30
25
20
RR of Mortality
15
(Hazard Ratio)
10
5
<15
15-29
30-44 Renal Function
45-59
(ml/min/1.73m2)
0
20-44
45-54
55-64
Age bands (years)
65-74
>60
75-84
85+
CKD
A leopard with changing spots?