Insulin resistance is an independent correlate of increased urine albumin excretion: a cross-sectional study in Iranian Type 2 diabetic patients.
OBJECTIVE
To assess the association of insulin resistance with increased urinary albumin excretion (UAE) in a cohort of Iranian Type 2 diabetic patients.


METHODS
Three hundred and sixty-one men and 472 women with Type 2 diabetes were enrolled from three different outpatient clinics (Tehran, Iran) during the period 2005-2008. Patients with obstructive uropathy, severe heart failure, liver disease, cancer, autoimmune disease and macroalbuminuria were not included. Microalbuminuria (MA; defined as UAE >or= 30 mg/day) was found in 242 (29.1%) patients; 591 (70.9%) subjects had normoalbuminuria (UAE < 30 mg/day). Insulin resistance was assessed using homeostasis model assessment of insulin resistance (HOMA-IR).


RESULTS
HOMA-IR index values were higher in subjects with MA than those with normoalbuminuria (P < 0.00001). Adjusted values (for age, sex and duration of diabetes) of UAE and HOMA-IR were 11.81 +/- 7.51 (mg/day) and 3.30 +/- 2.21 in normoalbuminuric and 75.36 +/- 55.57 (mg/day) and 4.98 +/- 3.22 in the MA group, respectively (P < 0.00001 for all). Multiple regression analysis showed that UAE was predicted by HOMA-IR, independently of age, duration of diagnosed diabetes, triglycerides, waist circumference, metabolic control, blood pressure and related treatments (P < 0.00001). When patients were categorized into quartiles of HOMA-IR, those of the fourth quartile (i.e. the most insulin resistant) were at a higher risk of increased UAE than other quartiles [odds ratio (OR) 3.7 (95% confidence intervals 2.7-6.2)].


CONCLUSIONS
In Iranian Type 2 diabetic patients, albuminuria was strongly associated with insulin resistance. HOMA-IR is an independent predictor of UAE.
Esteghamati
A
A
Department of Endocrinology, Endocrinology and Metabolism Research Center, Vali-asr Hospital, Tehran University of Medical Sciences/University of Tehran, Tehran, Iran. esteghamati@sina.tums.ac.ir
Ashraf
H
H
Nakhjavani
M
M
Najafian
B
B
Hamidi
S
S
Abbasi
M
M
D000328:Adult; D000419:Albuminuria / Q000453:epidemiology*; D001786:Blood Glucose / Q000032:analysis; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012307:Risk Factors; D012737:Sex Factors
D001786:Blood Glucose; D007328:Insulin