Implication of using estimated glomerular filtration rate (GFR) in a multi ethnic population of diabetes patients in general practice.
OBJECTIVE
To estimate the prevalence of chronic kidney disease (CKD) among diabetes patients in New Zealand, using estimated Glomerular filtration rate (eGFR); to measure the agreement between the Modification of Diet in Renal Disease (MDRD) and Cockcroft-Gault (CG) equations in identifying CKD among Europeans and Māori; to review the metabolic control and treatment in patients with evidence of CKD.


METHODS
Diabetes patients were identified though general practice records of diagnosis codes, diabetes annual reviews, prescriptions and laboratory results. The MDRD and CG equations were used to calculate the eGFR. Agreement between the two equations was expressed using Kappa statistics and was tested using McNemar's chi-square test. Logistic regression model was used to identify the predictors of CKD (eGFR<60 ml/min/1.73m2).


RESULTS
Overall prevalence of CKD among diabetes patients was 19.5% (MDRD) and 23.5% (CG). Maori were significantly more likely to have CKD [Odds-ratio 1.8(1.2-2.8)]. There were significant differences between the MDRD and the CG equations in identifying patients with CKD. While CG equation identifies more European of both genders, more Māori females were identified by MDRD.


CONCLUSIONS
Patients with decreased eGFR who do not have proteinuria or microalbuminuria might benefit from more intensive management of blood pressure. MDRD equation may be overestimating CKD among Māori females. Each ethnic subpopulation may need to be validated separately, and by gender.
Joshy
Grace
G
Waikato Clinical School, University of Auckland, Hamilton, New Zealand. joshyg@waikatodhb.govt.nz
Porter
Tesa
T
Le Lievre
Clem
C
Lane
Jane
J
Williams
Mike
M
Lawrenson
Ross
R
D017677:Age Distribution; D000368:Aged; D001794:Blood Pressure; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D003928:Diabetic Nephropathies / Q000175:diagnosis* / Q000178:diet therapy / Q000208:ethnology*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D011237:Predictive Value of Tests; D015995:Prevalence; D017678:Sex Distribution; D016896:Treatment Outcome; D044465:White People / Q000706:statistics & numerical data