Australian National Diabetes Information Audit & Benchmarking (ANDIAB) 2011 Final Report

2.7.4 Serum Creatinine and Glomerular Filtration Rate [GFR] Data

Data on the level of serum creatinine for individuals and on glomerular filtration rate

Page last updated: December 2011

Table 22 provides data on Serum Creatinine for individuals, as the percent of individuals in the (arbitrary) categories of: [below 120], [120-500] or [over 500] micromols per litre. See Frequency Tables for n= and range data.

Table 22 – Percent (%) Serum Creatinine

Serum Creatinine
[All n]
All Sites
n=3767
Adult Forms Only
n=3767
Paediatric Forms Only
n=0
< 120 Ámol / L
3204
85.1
120 - 500 Ámol / L
527
14.0
> 500 Ámol / L
36
1.0
See Tables on Pages 139-140 of Appendix 5 for Serum Creatinine Data. The Graphs show the spread/comparison of site’s results ranked in order for totals and broken down by Age. The pages are All sites data[A], which in 2011 is equivalent to Adult Forms data .

From 2002 onwards, we have undertaken Glomerular Filtration Rate [GFR] calculations. Rather than using the Cockcroft-Gault equation [which tends to over estimate low and under estimate hyper filtration], we have used the MDRD [Modified Diet in Renal Disease] Study15, 4 - variable formula [see below #] - (Serum Creatinine; Age; Height and Weight – with loading for female & ATSI). We have calculated GFR for all with appropriate data aged ≥20.
The results are shown in Tables 25 – [a] All patients [b] Type 1 and [c] Type 2.

The data have been converted to Low, Normal and High GFR based on sex and decade-specific age ranges as reported in the MDRD Study paper15 [which are based on their findings in non-diabetic individuals]. These compensate for the approximate 10 ml/min/1.73 sq.m GFR decline per decade over 40 years.

Prior to 2011 we had not requested participants to provide an eGFR [estimated GFR] result on their patients – an oversight [in retrospect] given that this is now a standard calculation undertaken and reported by all Laboratories across Australia. It was collected in 2011.


Table 25[d] provides data on the degree / severity of reduced eGFR [with retrospective calculations for 2004, 2006 and 2009 data – {not previously undertaken} – for comparison].

In addition in Table 25[d], for 2011 data only – where data are available, we have assessed the individuals stated to be on Metformin Therapy who have a calculated / estimated GFR of <=30, being n=16. This represents 0.6% of those patients stated to be on Metformin therapy.

Table 25[a] – GFR # (ml/min/1.73 sq.m) [All Patients]

Sex
Age
N
Low
Low %
Normal
Normal %
High
High %
Male
20-29
138
61
44.2%
66
47.8%
1
0.7%
30-39
160
46
28.8%
96
60.0%
2
1.3%
40-49
263
93
35.4%
139
52.9%
2
0.8%
50-59
487
137
28.1%
302
62.0%
4
0.8%
60-69
716
233
32.5%
403
56.3%
14
2.0%
70-79
477
141
29.6%
262
54.9%
21
4.4%
80+
147
46
31.3%
72
49.0%
16
10.9%
Total
2388
757
31.7%
1340
56.1%
60
2.5%
Female
20-29
185
73
39.5%
93
50.3%
6
3.2%
30-39
193
71
36.8%
87
54.1%
14
7.3%
40-49
231
57
24.7%
139
60.2%
14
6.1%
50-59
393
99
25.2%
236
60.1%
22
5.6%
60-69
501
145
28.9%
264
52.7%
41
8.2%
70-79
408
112
27.5%
203
49.8%
56
13.7%
80+
140
33
23.6%
72
51.4%
22
15.7%
Total
2051
590
28.8%
1094
53.3%
175
8.5%
Total
4439
1347
30.3%
2434
54.8%
235
5.3%

Table 25[b] – GFR # (ml/min/1.73 sq.m) [Type 1]

Sex
Age
N
Low
Low %
Normal
Normal %
High
High %
Male
20-29
126
57
45.2%
59
46.8%
1
0.8%
30-39
100
25
25.0%
62
62.0%
1
1.0%
40-49
76
21
27.6%
48
63.2%
0
0.0%
50-59
92
25
27.2%
53
57.6%
1
1.1%
60-69
39
10
25.6%
25
64.1%
1
2.6%
70-79
26
6
23.1%
18
69.2%
2
7.7%
80+
8
0
0.0%
7
87.5%
1
12.5%
Total
467
144
30.8%
272
58.2%
7
1.5%
Female
20-29
133
47
35.3%
75
56.4%
2
1.5%
30-39
94
26
27.7%
53
56.4%
2
2.1%
40-49
92
22
23.9%
53
57.6%
7
7.6%
50-59
65
17
26.2%
34
52.3%
3
4.6%
60-69
45
14
31.1%
22
48.9%
5
11.1%
70-79
14
3
21.4%
6
42.9%
3
24.4%
80+
8
3
37.5%
3
37.5%
0
0.0%
Total
451
132
29.3%
246
54.5%
22
4.9%
Total
918
276
30.1%
518
56.4%
29
3.2%

Table 25[c] – GFR # (ml/min/1.73 sq.m) [Type 2]

Sex
Age
N
Low
Low %
Normal
Normal %
High
High %
Male
20-29
11
4
36.4%
6
54.5%
0
0.0%
30-39
53
17
32.1%
31
58.5%
1
1.9%
40-49
117
70
39.5%
85
48.0%
2
1.1%
50-59
378
105
29.8%
239
63.2%
3
0.8%
60-69
652
215
33.0%
367
56.3%
13
2.0%
70-79
442
134
30.3%
238
53.8%
19
4.3%
80+
137
46
33.6%
64
46.7%
15
10.9%
Total
1850
591
31.9%
1030
55.7%
53
2.9%
Female
20-29
20
6
30.0%
12
60.0%
0
0.0%
30-39
40
14
35.0%
17
42.5%
4
10.0%
40-49
123
28
22.8%
81
65.9%
5
4.1%
50-59
316
79
25.0%
194
61.4%
19
6.0%
60-69
444
128
28.8%
236
53.2%
36
8.1%
70-79
385
105
27.3%
193194
50.1%
52
13.5%
80+
131
30
22.9%
69
52.7%
21
16.0%
Total
1459
390
26.7%
802
55.0%
137
9.4%
Total
3309
981
29.6%
1832
55.4%
190
5.7%

Table 25[d] – GFR # (ml/min/1.73 sq.m)

GFR
2004
2006
2009
2011
n
%
n
%
n
%
n
%
>60
1344
44.7
851
53.4
2381
40.7
2238
50.4
>45 and ?60
345
11.5
235
14.8
487
8.3
495
11.2
>30 and ?45
169
5.6
139
8.7
292
5.0
324
7.3
≤30
101
3.4
80
5.0
162
2.8
181
4.1
Missing
1049
34.9
288
18.1
2525
43.2
1201
27.1
≤30 and Meformin = Yes
Not Collected
Not Collected
32
1.1
16
0.6
Total
3008
1593
5847
4439
In 2011, having collected eGFR for the first time, we undertook the same analyses as shown in Table 25[d], and the results appear in Table 25[e].

Table 25[e] – eGFR

GFR
2011
n
%
>60
2781
60.5
>45 and ?60
489
10.6
>30 and ?45
289
6.3
≤30
207
4.5
Missing
832
18.1
≤30 and Meformin = Yes
16
0.7
Total
4598
These analyses shows more available eGFR results, with more individuals reportedly normal (>60) than in the MDRD calculations in Table 25[d] (60.5% versus 50.4%). The other results are similar with 4.5% having an eGFR ≤30 (versus 4.1% in Table 25[d]).

# GFR (mL/min/1.73sq.m) = GFR x 1.73 / SA
GFR (mL/min) = 186.3 x Serum Creatinine^-1.154 x Age^-0.203 x 1.212 (if ATSI) x 0.742 (if female)
SA = 0.007184 x height^0.725 x weight^0.425

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