[Assessment of renal function according to the NHG protocol 'Diabetes mellitus type 2': risk of overestimating the number of diabetes patients with renal dysfunction].
OBJECTIVE
To evaluate the consequences of the new Dutch College of General Practitioners (NHG) protocol 'Diabetes mellitus type 2', which recommends using either the Cockcroft-Gault (CG) formula or the 'Modification of diet in renal disease' (MDRD) study formula to determine the estimated glomerular filtration rate (eGFR) as an indicator of renal function, in a cohort of patients with type-2 diabetes.


METHODS
Inventory.


METHODS
The eGFR was calculated using the CG formula, the body-mass index (BMI-)corrected CG formula and the MDRD formula in 6224 patients with type-2 diabetes who entered the 'Zwolle outpatient diabetes project integrating available care' (ZODIAC) study in 2005.


RESULTS
Using the CG and MDRD formulas, 31% and 63% of patients, respectively, had an eGFR of 30-59 ml/min (units for MDRD are ml/ min/1.73 m2) for which referral is advisable. In addition, 1% and 11%, respectively, had an eGFR <30 ml/min (reference: >90 ml/min), for which referral is necessary. Most patients aged >70 years (or > 50 years using the BMI-corrected CG formula) had an eGFR <60 ml/min.


CONCLUSIONS
Reduced eGFR can be a sign of renal dysfunction but, using these formulas, can also be partly explained by advanced age. Therefore other factors should be considered when interpreting the results ofeGFR before it is concluded that the patient has kidney disease and the associated increased risk of cardiovascular disease.
Bilo
H J G
HJ
Universitair Medisch Centrum Groningen, afd. Inwendige Geneeskunde, Groningen. h.j.g.bilo@isala.nl
Logtenberg
S J J
SJ
Dikkeschei
L D
LD
Kleefstra
N
N
Wolffenbuttel
B H R
BH
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000465:Algorithms; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis*; D007677:Kidney Function Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged
D003404:Creatinine