Clinical and biochemical characteristics and the association of angiotensin type 1 receptor with normoalbuminuric chronic kidney disease among South Indian type 2 diabetes population

Abstract

The aim of the study was to determine the clinical and biochemical characteristics especially cystatin C and the association of angiotensin type I receptor (AT1R) gene polymorphism with normoalbuminuric chronic kidney disease (NACKD) among South Indian type 2 diabetes (T2DM) population. The study comprised of 308 (M:F 190:118) subjects with T2DM categorized into three groups. Group I: T2DM patients without albuminuria (NA) and estimated glomerular filtration rate (eGFR) > 90 ml/min/1.73m2 (n = 110); group II: T2DM patients with albuminuric chronic kidney disease (CKD) with eGFR < 60 ml/min/1.73m2 (n = 98); and group III: T2DM patients with normoalbuminuric CKD (NACKD) and eGFR < 60 ml/min/1.73m2 (n = 100). The eGFR was estimated using the Modification of Diet in Renal Disease (MDRD) formula. Cystatin C was measured by particle-enhanced immunoturbidimetric assay. AT1R gene polymorphism was analyzed using the PCR-RFLP method. The biochemical parameters urea, creatinine, post prandial glucose, HbA1c, triglycerides, cystatin C levels, erythrocyte sedimentation rate (ESR), and diastolic blood pressure were lower and the levels of calcium were higher in normoalbuminuric CKD subjects as compared to albuminuric CKD subjects. The AT1R genotypic distribution of AA, AC, and CC was 80.2%, 19.8%, and 0% in NACKD, and 95.1%, 4.9%, and 0% in CKD subjects. The distribution of allelic frequencies of A and C allele in NACKD was 90.1% and 9.9%, and in CKD, it was 97.6% and 2.4% respectively. The relative risk of AC (p = 0.08) genotype and C (p = 0.01) allele in NACKD was 4 times higher as compared to CKD. The present study highlighted that the clinical and biochemical parameters showed significant differences especially cystatin C whose levels increased in normoalbuminuric CKD subjects as compared to normoalbuminuric subjects. Significant association of AGTR1 A1166C polymorphism was observed in normoalbuminuric CKD subjects as compared to CKD subjects with T2DM.